554 Sentences With "most basal" | Random Sentence Generator

This animal is considered the most basal, or most primitive, non-flying dinosaur to be equipped with feathered proto-wings.

Image: Karl-Goran Sjogren/University of GothenbergAs noted, the Gok9003 strain is the oldest that's ever been discovered, but it's also the most basal.

Within the genus, the puffadder shyshark is the most basal species.

Hughmilleria socialis. Hughmilleria is the most basal known genus in the Pterygotioidea.

Utaherpeton was still recovered as one of the most basal "microsaurs", but not as the most basal lepospondyl. Tentative support for a close relationship between Utaherpeton and Microbrachis was also found. In a 2010 analysis, all "microsaurs" except Utaherpeton were recovered within a monophyletic group, but Utaherpeton was found to be the most basal member of a separate clade that included all other lepospondyls.

Eriphostoma is the most basal member of an endemic African radiation of gorgonopsians.

Pablo Nuñez Demarco et al. Was Mesosaurus a Fully Aquatic Reptile? Front. Ecol. Evol, published online July 27, 2018; doi: 10.3389/fevo.2018.00109 Similarly, their affinities are uncertain; they may be either the most basal sauropsids, or among the most basal parareptiles.

Lycosuchids are the earliest known therocephalians and are also thought to be the most basal.

Within Chaeomysticeti, Sitsqwayk is recovered as the most basal chaeomysticete, more primitive than eomysticetids and Horopeta.

Most basal Eudicots are dimerous or trimerous, with only occasionally pentamerous types which represent homoplasious trends.

However, they had a widespread distribution. Phuwiangvenator and Fukuiraptor, the most basal and second most basal known members of the group, lived in Thailand and Japan, respectively. Megaraptoran material is also common in Australia, and the largest known predatory dinosaur from the continent, Australovenator, was a megaraptoran.

Comparison of azhdarchoid mandibles A phylogenetic analysis conducted in 2016 recovered Aymberedactylus as the most basal tapejarine.

Postcranial data and a full dataset suggests that the clade Ophiacodontidae and Varanopidae is the most basal clade.

Proneotherium represents some of the most basal members of Odobenidae. The sister group is the closely related Prototaria.

In 2011, Martinez et al. described Eodromaeus, a basal theropod from the same formation as Herrerasaurus. In a phylogenetic analysis, Eoraptor was placed within Sauropodomorpha, Herrerasauridae was placed as the most basal theropods, and Eodromaeus was placed as the next most basal. A more recent analysis, by Bittencourt et al.

The most basal clade within Megalosauroidea contains Condorraptor, Marshosaurus, Piatnitzkysaurus and Xuanhanosaurus. The next most basal clade comprises Chuandongocoelurus and Monolophosaurus. However, the affiliation of these clades with Megalosauroidea is poorly supported by tree support metrics, and it is possible that they will be classified outside of Megalosauroidea by future analyses.

In most basal archosauriforms, the quadrate is tall and straight, but in Vancleavea it is short, stout, and arched forwards.

The Anthiinae are sometimes placed within the Serraninae but these fishes are mainly deepwater species and have a soft ray count in the anal fin with a mode of eight. The subfamily is the most basal of the three subfamilies within the Serranidae, with the genus Centropristis being the most basal in the Serraninae.

Captorhinidae (also known as cotylosaurs) is one of the earliest and most basal reptile families, all members of which are extinct.

Geological Society, London, Special Publications 315: 229-243. It is considered to be the most basal member of the group Trionychoidae.

Lithogenes is the only genus within the subfamily Lithogeneinae. This genus and subfamily, the most basal group in Loricariidae, is the sister group to the rest of the family. Neoplecostominae are the most basal group among the loricariids with the exception of Lithogeneinae. However, the genera of Neoplecostominae do not appear to form a monophyletic assemblage.

Ctenocystoids are likely among the most basal stem-group echinoderms. They have also been interpreted as aberrant blastozoans and as stem-group hemichordates. The presence of stereom plates indicates that they most likely belong to the echinoderm total group, rendering a hemichordate affinity unlikely. Courtessolea was probably the most basal ctenocystoid, given its anatomical similarities to Ctenoimbricata and cinctans.

In addition, the two were found to be the second-most basal taxa in their genus, after the common stingray (D. pastinaca).

These groups could be differentiated morphologically by the colour of the stalk when dried. The most basal was shown to be L. atrovirens.

Most uncertainty in the phylogeny of synapsids lies among the earliest members of the group, including forms traditionally placed within Pelycosauria. As one of the earliest phylogenetic analyses, Brinkman & Eberth (1983) placed the family Varanopidae with Caseasauria as the most basal offshoot of the synapsid lineage. Reisz (1986) removed Varanopidae from Caseasauria, placing it in a more derived position on the stem. While most analyses find Caseasauria to be the most basal synapsid clade, the analysis of Benson (2012) placed a clade containing Ophiacodontidae and Varanopidae as the most basal synapsids, with Caseasauria occupying a more derived position.

Together, Odatria, Varanus, and Papusaurus form a monophyletic clade of Indo-Australopapuan monitors. The same study found the black-palmed rock monitor, the largest species within Odatria, as sister to the rest of Odatria, making it the most basal species within the subgenus. Vidal et al. 2012 also recovers this species as the most basal, although within the V. tristis group.

Sinaspideretes is an extinct genus of turtle from the Late Jurassic of China. It is considered the earliest and most basal representative of the Trionychia.

Cruxicheiros was a tetanuran, a member of the dinosaur group Tetanurae which also includes theropods such as Tyrannosaurus and Spinosaurus. The describers did not place Cruxicheiros in any family. They performed a cladistic analysis which rendered three equally probable positions for Cruxicheiros: as the most basal neotetanuran (the line which gave rise to dinosaurs like Allosaurus and birds), as the most basal megalosauroid (the line which led to Megalosaurus and Spinosaurus), or as the most basal member of the Tetanurae, whose earliest members must have predated the split between these theropod groups. In view of the uncertainties they classified Cruxicheiros as Tetanurae incertae sedis.

Journal of Paleontology. 50 (5): 808–820. . Butler et al. (2010) found the Heterodontosauridae to be the most basal known significant ornithischian radiation.R. J. Butler. 2010.

Chippewaella patellitheca is a stem-gastropod mollusc from Furongian-aged strata of Late Cambrian Wisconsin. According to Peter J. Wagner, it is the most basal gastropod.

The most basal segment, or coxae, are subtriangular. Their abdomen has nine rows of two- dorsal central abdominal seta and one fairly long dorsal lateral abdominal seta.

Phytosaurs are generally regarded as the most basal group of Crurotarsi, a clade of archosaurs that includes crocodilians and their extinct relatives. Phytosaurs are often excluded from a clade called Suchia, which usually encompasses all other crurotarsans, including aetosaurs, rauisuchians, and crocodylomorphs. Some studies have found polytomies between phytosaurs and other groups, like Ornithosuchidae and Suchia. In these cases, it is unclear whether phytosaurs are the most basal crurotarsans.

The leafhoppers are the most basal living lineage of Membracoidea, which otherwise include the families Aetalionidae (aetalionid treehoppers), Membracidae (typical treehoppers and thorn bugs), Melizoderidae and the strange Myerslopiidae.

The Taeniidae, including species such as the pork tapeworm and the beef tapeworm that often infect humans, may be the most basal of the 12 orders of the Cyclophyllidea.

All but the most basal forms exhibit this wing coupling. There are three different types of mechanisms – jugal, frenulo–retinacular, and amplexiform.Scoble (1995). Section "Wing coupling", (pp. 56–60).

Callichthys is the most basal member of the subfamily Callichthyinae. Linnaeus described the first species in this genus in 1758, but three other members have been found since 1999.

Here, the Aetiocetidae is the sister taxon to Eomysticetus+ Micromysticetus + Diorocetus + Pelocetus + crown Mysticeti. In their sample, Aetiocetus is the second-most basal mysticete; two undescribed museum specimens, ChM, are considered the most basal mysticetes in this phylogeny. In Geisler et al.’s 2011 study entitled “A supermatrix analysis of genomic, morphological, and paleontological data from crown Cetacea”, there is higher resolution of Aetiocetus’ phylogenetic relationship with other mysticetes, as well as more taxa considered.

The APG system, of 1998, also recognized this family, but left it unplaced as to order, and regarded it as being among the most basal lineages in the clade angiosperms.

Evolution and Palaeobiology of Pterosaurs. Geological Society Special Publications 217. Geological Society of London applying Kellner's terminology it is the most basal offshoot within the Novialoidea.Kellner, A. W. A. (2003).

The family is noted to be the most basal group of hymenopterans in the suborder Apocrita. Sharkey et. al. (2012) Phylogenetic relationships among superfamilies of Hymenoptera. Cladistics 28: 80-112.

The most basal of living actinopterygians are the bichirs, a small group of African fishes previously thought to be related to the lobefin fishes, or to form a third group.

The APG IV system, of 2016, recognizes this family and places it in order Austrobaileyales, an order which is accepted as being among the most basal lineages in the clade angiosperms.

A 2020 phylogenetic analysis suggests that this species is the most basal species in the genus Varanus, having dispersed to the Solomon Islands shortly after they formed 30 million years ago.

Rakiura is a genus of Trichoptera (caddisfly). The genus contains only one species, R. vernale, which is endemic to New Zealand. Rakiura vernale represent the most basal taxon within the Helicopsychidae.

Holopterygius is an extinct genus of prehistoric eel-like coelacanth. Despite its specialized morphology and superficial disimilarity to the usual coelacanth body plan it's one of the most basal actinistian fish.

Below is a cladogram of the most commonly accepted phylogeny of synapsids, showing a long stem lineage including Mammalia and successively more basal clades such as Theriodontia, Therapsida and Sphenacodontia: Most uncertainty in the phylogeny of synapsids lies among the earliest members of the group, including forms traditionally placed within Pelycosauria. As one of the earliest phylogenetic analyses, Brinkman & Eberth (1983) placed the family Varanopidae with Caseasauria as the most basal offshoot of the synapsid lineage. Reisz (1986) removed Varanopidae from Caseasauria, placing it in a more derived position on the stem. While most analyses find Caseasauria to be the most basal synapsid clade, Benson's analysis (2012) placed a clade containing Ophiacodontidae and Varanopidae as the most basal synapsids, with Caseasauria occupying a more derived position.

Zheng et al. (2015), the describers of Mosaiceratops, recovered the genus as the most basal known neoceratopsian, closer to Triceratops than Psittacosaurus. Before the description of Mosaiceratops, the most basal known neoceratopsian was either Aquilops or Liaoceratops, depending on the analysis. However, they noted that this position was not strongly supported in their phylogenetic analysis, acknowledging the possibility that Mosaiceratops instead represents the sister taxon to Psittacosaurus (in which case the name Psittacosauridae would be reinstated).

There are three tarsal segments (tarsomeres), of which the most basal one is twice as long as the others. The pair of tarsal claws lack the ventro- apical hook of modern odonates.

Specimens belonging to the species were previously misidentified as those of the similar captorhinid Labidosaurus hamatus. Reiszorhinus is one of the most basal captorhinids, along with the genera Romeria, Concordia, and Protocaptorhinus.

Ateleaspis possibly is the most basal vertebrate with paired fins. Ateleaspis was a small fish (about 15 – 20 cm) and had a flat headshield a narrow trunk covered by brick-like scales.

As in many other genera, there is a tendency for the embolus to increase in length. Both the most basal (Palfuria panner) and the most derived species (Palfuria spirembolus) are found in Namibia.

The APG III system, of 2009, also recognizes such a family and places it in order Austrobaileyales, an order which is accepted as being among the most basal lineages in the clade angiosperms.

The APG II system, of 2003, also recognizes such a family and places it in order Austrobaileyales, an order which is accepted as being among the most basal lineages in the clade angiosperms.

Oromycter is the oldest and most basal caseid known, and is the sister taxon of all other caseids. Below is a cladogram based on the phylogenetic analysis of Maddin et al. in 2008.

It comprises a single species, Nuttalliella namaqua,Guglielmone et al. (2010)Goddard (2008): p. 80 and is the most basal lineage. It is found in southern Africa from Tanzania to Namibia and South Africa.

Rastodon is an extinct genus of anomodonts. It is the oldest and most basal known genus of bidentalian dicynodonts. Uniquely among dicynodonts, its tusks curve forward. The type and only species is R. procurvidens.

Of those other families, the Meropeidae is the most basal, and the relationships of the rest are not completely clear. Panorpa dubia. A, Body in lateral view; B–D. male genital bulb and gonostyli.

2nd ed. Berkeley (CA): University of California Press. p. 363–392 However, new material of the skeleton confirms the original identification of Carpenter et al. of Cedarpelta being one of the most basal ankylosaurids.

It comprises the most basal living lineage of skippers. In Coeliadinae the second segment of the palpi is erect and densely scaled, and the third segment is perpendicular to it, long, slender and without scales.

The APG III and APG IV systems of classification separated the family Cabombaceae from the family Nymphaceae. The family is part of the order Nymphaeales, which is one of the most basal flowering plant lineages.

Pakicetus is an extinct genus of amphibious cetacean of the family Pakicetidae, which was endemic to Pakistan during the Eocene.. Retrieved June 2013. The vast majority of paleontologists regard it as the most basal whale.

The species of Pseudobunocephalus were originally classified in the genus Bunocephalus, but after further study it was found that these fish were unrelated to the type species Bunocephalus verrucosus or any of the other existing aspredinid genera. Thus, a new genus was described in 2008. Pseudobunocephalus is the most basal genus in the family, and represents the sister group to all other Aspredinidae. P. lundbergi is also the most basal species and is the sister taxon to the rest of the species in the genus.

Diagram of the holotype specimen with insert photos showing traits shared with phytosaurs A phylogenetic analysis conducted by Li et al. (2012) in the original description of Diandongosuchus showed that it was the most basal member of a clade called Poposauroidea, which includes mostly terrestrial pseudosuchians such as the bipedal Poposaurus and the sail-backed Arizonasaurus. It was found to be closely related to Qianosuchus, an aquatic pseudosuchian that was the second most basal member of Poposauroidea. The data matrix of Li et al.

Lower jaw A study by Maidment indicated that Gigantspinosaurus is the most basal known member of the Stegosauria. Peng and colleagues, however, placed it in the Huayangosaurinae. A 2018 redescription by Hao et al clarified aspects of the anatomy and found that it was an intermediate basal stegosaur, sharing basal traits with huayangosaurines as well as somewhat more advanced traits with other stegosaurs. Nevertheless, this analysis found that it was not the most basal stegosaur, as the huayangosaurids Chungkingosaurus and Huayangosaurus were considered more basal.

Oleaceae is most closely related to the small Indo-Malesian family Carlemanniaceae. These two families form the second most basal clade in the order Lamiales, after Plocospermataceae.Peter F. Stevens (2001 onwards). "Oleaceae" At: Angiosperm Phylogeny Website.

Schulze also conducted important investigations of delicate sponge-like protozoans known as xenophyophores. In 1883, Schulze was the first to describe Trichoplax adhaerens, one of the most basal multicellular animals and member species of the phylum placozoa.

This subfamily is the most basal clade in Loricariidae with the exception of Lithogeneinae. The genera do not form a monophyletic assemblage. Neoplecostominae is not diagnosed by any unique characteristic. However, molecular studies have supported this grouping.

Tapinocaninus is an extinct genus of therapsids in the family Tapinocephalidae, in which it is the most basal member. Only one species is known, Tapinocaninus pamelae (meaning "Pam's humble canine").Living during the Middle Permian (Wordian age).

Phylogenetic analysis indicates that it is one of the most basal members of Crocodyloidea and a close relative of Arenysuchus from the Late Cretaceous of Spain, although the incomplete nature of known material makes these findings uncertain.

Study of their evolutionary position has been problematic due to difficulties in phylogenetic analysis arising from long branch attraction. The most basal strepsipteran is the fossil Protoxenos janzeni discovered in Baltic amber, while the most basal living strepsipteran is Bahiaxenos relictus, the sole member of the family Bahiaxenidae. The earliest known strepsipteran fossils are those of Cretostylops engeli, Kinzelbachilla ellenbergeri, Phthanoxenos nervosus and Heterobathmilla kakopoios, discovered in middle Cretaceous Burmese amber from Myanmar. In 2012, a fresh molecular study revived the assertion that the Stepsiptera are the sister group of the Coleoptera (beetles).

Like all non-avian dinosaurs, the sauropodomorphs became extinct 66 Mya, during the Cretaceous–Paleogene extinction event. The earliest and most basal sauropodomorphs known are Chromogisaurus novasi and Panphagia protos, both from the Ischigualasto Formation, dated to 231.4 million years ago (late Carnian age of the Late Triassic according to the ICS (Warning: abstract is 12 kb PDF)). Some studies have found Eoraptor lunensis (also from the Ischigualasto Formation), traditionally considered a theropod, to be an early member of the sauropodomorph lineage, which would make it the most basal sauropodomorph known.

Cephalanthus is the most basal genus in the tribe Naucleeae.Manns, U. and B. Bremer. 2010. Towards a better understanding of intertribal relationships and stable tribal delimitations within Cinchonoideae s.s. (Rubiaceae). Molecular Phylogenetics and Evolution 56(1), 21-39.

The most basal extant frog species are in the Archeabatrachia suborder. The most primitive frog is arguably Leiopelma. Salienta fossils are the earliest examples of anurans that show a split from Order Caudata. Examples include Triadobatrachus and Czatkobatrachus.

Pennantiaceae consists of the single genus Pennantia and is the most basal clade in the campanulid order Apiales.Jesper Kårehed. 2003. "The family Pennantiaceae and its relationships to Apiales". Botanical Journal of the Linnean Society 141(1):1-24.

Paraburnetia belongs to the clade burnetiidae, a subdivision of the greater clade biarmosuchian therapsids.Angielczyk, K. D., & Schmitz, L. (2014). Nocturnality in synapsids predates the origin of mammals by. Biarmosuchians are typically considered the most basal major lineage of therapsids.

Although it is known that Scandentia is one of the most basal Euarchontoglire clades, the exact phylogenetic position is not yet considered resolved, and it may be a sister of Glires, Primatomorpha or Dermoptera or to all other Euarchontoglires.

Biarmosuchians are typically considered the most basal major lineage of therapsids. Biarmosuchia consists of a paraphyletic series of basal biarmosuchians that are fairly typical early therapsids, and the derived clade Burnetiamorpha, characterized by skulls ornamented by horns and bosses.

Scylacosauria is a clade of therocephalian therapsids. It includes the basal family Scylacosauridae and the infraorder Eutherocephalia. Scylacosauridae and Eutherocephalia form this clade to the exclusion of Lycosuchidae, the most basal therocephalian family. Thus, Scylacosauria includes all therocephalians except lycosuchids.

The monotypic genus Tomopeas, represented by the blunt-eared bat (Tomopeas ravus), is acknowledged as the potentially closest link between the Vespertilionidae and Molossidae, as it is the most basal member of the Molossidae and has intermediate characteristics of both families.

Within the European clade the Volga pikeperch (S. volgaensis) is the most basal taxon and shares features with the North American clade, such as being a broadcast spawner. In contrast in the zander (S. lucioperca) and the estuarine perch (S.

A 2006 phylogenetic analysis by J. Andrés López and colleagues, based on protein-coding genes, revealed that Triakis and Cazon are in fact not closely related, and additionally that the leopard shark may be the most basal member of its family.

Plant Systematics and Evolution 232:213-236. Within its family, the Fagaceae, recent research has suggested that Fagus is the evolutionarily most basal group.Manos, Paul S. with Kelly P. Steele. 1997. Phylogenetic analysis of “Higher” Hamamelididae based on Plasid Sequence Data.

The affinities of this skeleton are uncertain, and it has only been briefly described. Holtz et al. (2004) included it in their phylogenetic analysis and found it to be the most basal tetanuran.Holtz, T.R., Molnar, R.E., Currie P.J. (2004): Basal Tetanurae.

Relationships between B. ilicifolia and the other members of B. subg. Isostylis still remain unclear. Although DNA studies found B. cuneata to be the most basal of the three species, a 2004 study of genetic divergence within the subgenus yielded both other possibilities: some analyses suggested B. ilicifolia as basal, while others suggested B. oligantha. Biogeographical factors suggest that B. ilicifolia would be the most basal of the three species: it occurs in the High Rainfall Zone where relictual species are most common, whereas the others are restricted to the Transitional Rainfall Zone, where more recently evolved species are most common.

Pentaedrusaurus is an extinct genus of procolophonid parareptile from the Early Triassic of China. It is one of the most basal members of the procolophonid subfamily Leptopleuroninae. The only known species of Pentaedrusaurus, P. ordosianus, was named in 1989 from the Heshanggou Formation.

Scylacosauridae is an extinct family of therocephalian therapsids. Scylacosaurids lived during the Permian period and were among the most basal therocephalians. The family was named by South African paleontologist Robert Broom in 1903. Scylacosaurids have long snouts and unusual saber-like canine teeth.

L. stellatum and L. ucamara are hypothesized to form a partially unresolved polytomy with L. pectorale and L. beni, which are sister-species to each other. L. tordilho is sister to these four species and L. altamazonicum is the most basal species.

Megadermatidae is a family within the Rhinolophoidea superfamily. Genetic analysis shows that it is the most basal member of the superfamily. It is a monophyletic family of bats, based on genetic analysis. There is confusion about the relationship of species within Megadermatidae.

Yi was placed in the Scansoriopterygidae, a group of maniraptoran theropods. A cladistic analysis failed to resolve its exact relationships with the other known scansoriopterygids, Epidendrosaurus and Epidexipteryx. In the analysis the Scansoriopterygidae was recovered as the most basal clade of the Paraves.

There are currently three subgenera in the genus Salvelinus: Baione, Cristovomer, and Salvelinus sensu stricto. Baione, the most basal clade in the genus, contains the brook trout (S. fontinalis), and the presumably extinct silver trout (S. agassizii). Cristovomer contains only the lake trout (S. namaycush).

Howlader MSA, Nair A, Merilä J (2016) A New Species of Frog (Anura: Dicroglossidae) Discovered from the Mega City of Dhaka. PLoS ONE 11(3): e0149597. doi:10.1371/journal.pone.0149597 11 species are included. Both phylogenetic trees place Zakerana mudduraja as the most basal species.

Plant systematists often use it as a typical member of Nymphaeaceae, which (other than Amborella) is the most basal of the flowering plants.Judd, W. S., C. S. Campbell, E.A. Kellogg, P. F. Stevens, and M. J. Donoghue. 2002. Plant Systematics: A Phylogenetic Approach. 2nd edn.

Rieppel, C. (1994). The status of Anarosaurus multidentatus von Huen (Reptilia, Sauropterygia), from the Lower Anisian of the Lechtaler Alps (Arlberg, Austria). Paläontologische Zeitschrift 69(1-2):289-299. Certain aspects of its morphology also suggest it is one of the most basal forms.

The other two genera are Urania, its sister taxon, and Alcides, the most basal. In the group, the use of Endospermum is an ancestral state (a plesiomorphy). The more basal Alcides feed on Endospermum and Omphalea, while Urania and Chrysiridia feed only on Omphalea.

Pachycormus has generally been considered basal among Pachycormiformes, with a recent phylogeny finding it to be the second most basal pachycormiform after Euthynotus. It was up to 1 m (3.5 ft) in length. Its ecology has been interpreted as that of a generalist predator.

Asteroxylon ("star-shaped xylem") is an extinct genus of vascular plants of the Division Lycopodiophyta known from anatomically preserved specimens described from the famous Early Devonian Rhynie chert and Windyfield chert in Aberdeenshire, Scotland. Asteroxylon is considered the most basal member of the Lycopsida.

Gross has formerly placed Andreolepis in the family Lophosteidae, but considering the distinct differences between the genera Lophosteus and Andreolepis, the latter was placed in the new family Andreolepididae. These two genera form the oldest and most basal osteichthyans that are known thus far.

Restoration of Panphagia, one of the most basal sauropodomorphs known. Plateosaurus is a well-known prosauropod. Sauropodomorpha is one of the two major clades within the order Saurischia. The sauropodomorphs' sister group, the Theropoda, includes bipedal carnivores like Velociraptor and Tyrannosaurus; as well as birds.

A phylogenetic analysis of dissorophids published in 2013 found Scapanops to be one of the most basal members of a clade called Eucacopinae. Eucacopines are characterized by their lightly built skeletons and knobby skulls. The most basal eucacopine was found to be Conjunctio while Scapanops was positioned close to a derived clade of eucacopines that includes the genus Cacops (which is also from the Early Permian of the southwestern United States) and the Russian genera Zygosaurus and Kamacops. While members of the derived eucacopine clade have two rows of osteoderms down their backs, Scapanops and Conjunctio have only a single row of osteoderms down their backs.

They also considered Onychopterella the most basal (primitive) member of the suborder Eurypterina (in which the sixth appendage is modified in a swimming leg), mainly because of the narrowness of the swimming leg and its distal spine, resulting in a better model for a primitive swimming leg than other derived members of Eurypterina such as Dolichopterus, ending in a large plate. The species O. pumilus was not included in the analysis because of its possible affiliation with Drepanopterus. In 2011, Lamsdell recovered Onychopterella as monophyletic (a group consisting of all the descendants of the last common ancestor, i.e. a valid genus), considering Moselopteroidea the most basal eurypterine clade.

The following cladogram follows an analysis by Fischer and colleagues in 2017, based on a dataset published by Benson and Druckenmiller in 2014 that was previously modified for the description of Makhaira in 2015. Due to the completeness of Luskhan, its position is based on scorings for 74% of the characteristics listed in the dataset. In the strict consensus of the 20,000 most parsimonious phylogenetic trees recovered, Makhaira forms a polytomy with Pliosaurus species, instead of forming a clade with other brachauchenines; however, in the consensus of the 24 most parsimonious trees, it is the most basal brachauchenine, with Luskhan being the next most basal brachauchenine.

Microleter is one of the most basal parareptiles, and was originally described as the most basal parareptile from Laurasia. Before the description of Microleter, parareptiles were hypothesized to have originated in Gondwana. However, Microleter appears in Laurasia soon after the earliest known parareptiles, and spurred discussion supporting the origin of parareptiles in Laurasia. Other factors in support of a Laurasian origin are the early appearance of the Laurasian bolosaurians, the fact that the other two clades of amniotes, synapsids and eureptiles, are both considered to have been Laurasian in origin, and evidence from varanopids that colonization of Gondwana by Laurasian amniotes was more common than the reverse process.

When Utaherpeton was first described in 1991, it was tentatively classified within a group of "microsaurs" called Microbrachomorpha, which included the better-known Microbrachis. A 2001 phylogenetic analysis found Utaherpeton to be the most basal lepospondyl, followed by the "microsaur" Hyloplesion, which has also been considered a microbrachomorph. However, Microbrachomorpha was not recognized as a true clade because Microbrachis was found to be more deeply nested within Lepospondyli, more closely related to derived lepospondyls like nectrideans and aïstopods than to other "microsaurs". A 2004 analysis including Utaherpeton produced a very different phylogeny for lepospondyls, placing aïstopods and nectrideans as the most basal lepospondyls, followed by a paraphyletic assemblage of "microsaurs".

Pelecanimimus was by the describers assigned to the Ornithomimosauria, in the basalmost position. A later cladistic analysis by Makovicky et al. (2005) confirmed that Pelecanimimus is the most basal member of the Ornithomimosauria, less derived even than Harpymimus.Makovicky, P., Kobayashi, Y. and Currie, P. J. (2004).

Size comparison As it is the most basal stegosaurian, it is placed in within its own family Huayangosauridae. It is also morphologically distinct from later (stegosaurid) forms. Its skull was broader and had premaxillary teeth in the front of its mouth. All later stegosaurians lost these teeth.

Placodontiformes is an extinct clade of sauropterygian marine reptiles that includes placodonts and the non-placodont Palatodonta. It was erected in 2013 with the description of Palatodonta. Placodontiformes is the most basal clade of Sauropterygia and the sister group of Eosauropterygia, which includes all other sauropterygians.

The following cladogram was produced by Albert Prieto-Márquez and his colleagues in 2013, it shows the phylogeny of Lambeosaurinae. Aralosaurus is closely related to Canardia and both genera are included in the tribe of Aralosaurini, which are identified as the most basal members of Lambeosaurinae.

Bayomesasuchus is an extinct genus of peirosaurid mesoeucrocodylian known from the early Late Cretaceous Cerro Lisandro Formation of Neuquén Province, western central Argentina. It contains a single species, Bayomesasuchus hernandezi. Even though it is known from relatively fragmentary remains, it represents one of the most basal peirosaurids.

Finally, biogeographical factors suggest that B. ilicifolia would be the most basal of the three species: it occurs in the High Rainfall Zone where relictual species are most common, whereas the others are restricted to the Transitional Rainfall Zone, where more recently evolved species are most common.

It has been traditionally assumed that mammutids are the most basal group within Elephantimorpha, with gomphotheres being more closely related to elephants. However recent molecular and mophological evidence suggests that trilophodont gomphotheres and mammutids are more closely related to each other than they are to elephants.

Iguanodontians are a diverse but morphologically tight knit array of genera known from fossils of the late Cretaceous. Significant modifications include the evolution of tooth batteries, a ligament-bound metacarpus and a digitigrade hand posture. Tenontosaurus is the most basal iguanodontian. Others include Iguanodon, Camptosaurus and Muttaburrasaurus.

Acanthomeridion is considered a primitive member of Artiopoda. Some studies have put it as having affinities with petalopleurans or xandarellids, but a more recent study by Hou, Williams et al. including the more recently discovered specimens suggest that it is the most basal member of the clade.

Carnufex is a primitive crocodylomorph, a group including suchians more derived than Rauisuchidae. It is the most basal of the group, along with an unnamed genus. Zanno et al. (2015) conducted a phylogenetic analysis, including taxa as basal as Mesosuchus and as derived as Protosuchus and Alligator.

Ctenoimbricata is an extinct genus of bilaterally symmetrical echinoderm, which lived during the early Middle Cambrian period of what is now Spain. It contains one species, Ctenoimbricata spinosa. It may be the most basal known echinoderm. It resembles the extinct ctenocystoids and cinctans, particularly the basal ctenocystoid Courtessolea.

The family Tofieldiaceae was erected by Armen Takhtajan in 1995.Tofieldiaceae. At: International Plant Names Index. (see External links below). Molecular phylogenetic studies of DNA sequences have shown it to be the second diverging clade in Alismatales, after the most basal clade, the family Araceae.Peter F. Stevens (2001 onwards).

Bonner Zoologische Beiträge, 42, 237-239. A morphological study suggested that it may be the most basal (earliest offshoot) of its genus,Velazco, P. M. (2005). Morphological phylogeny of the bat genus Platyrrhinus Saussure, 1860 (Chiroptera: Phyllostomidae) with the description of four new species. Fieldiana Zoology, 1-53.

A phylogenetic analysis conducted by González Riga and colleagues in 2018 recovered Mendozasaurus as the most basal member of Lognkosauria, including Futalognkosaurus and the gigantic titanosaurs Argentinosaurus, Notocolossus, Patagotitan and Puertasaurus. The following cladogram shows the position of Mendozasaurus in Lognkosauria according to González Riga and colleagues, 2018.

This tribe is a well diagnosed monophyletic group currently containing three genera: Pogonopoma, Pseudorinelepis, and Rhinelepis. When the tribe was first described, Pogonopomoides was a valid genus, but it is now a synonym of Pogonopoma. Pseudorinelepis is the most basal, and Rhinelepis and Pogonopoma are more derived sister groups.

They found George's B. ser. Cyrtostylis to be highly polyphyletic, and transferred a number of taxa into other series. B. lindleyana resolved as one of the most basal species of B. subg. Banksia, after B. elegans and a small clade consisting of B. elderiana and B. ser. Tetragonae.

Therefore, blunt-snouted forms did not form a single, specialized group, but rather a collection of basal taxa, some of which were ancestral to modern forms such as Alligator. Alligator is usually recovered as a monophyletic group with A. prenasalis as the most basal member of the clade.

They are classified based on their flagellar structures, and they are considered to be the most basal Flagellate lineage. Phylogenomic analyses split the members of the Excavates into three different and not all closely related groups: Discobids, Metamonads and Malawimonads. Except for Euglenozoa, they are all non-photosynthetic.

The uniqueness of the Laotian rock rat was clear upon its initial discovery. The results of the phylogenetic analyses were somewhat inconclusive and contradictory. Both morphological and molecular studies suggested Laonastes is a member of the rodent suborder Hystricognathi. The morphological analysis suggested it is the most basal hystricognath.

This would mean that both dimorphodontid species would be the most basal pterosaurs known with the exception of Preondactylus. According to Alexander Kellner, however, Dimorphodon is far less basal and not a close relative of Peteinosaurus. The cladogram recovered by Andres and Myers in 2013 is reproduced below.

It was originally classified within Microsauria, a group of superficially lizard- and salamander-like lepospondyls that is now no longer considered to be a valid clade or evolutionary grouping, but rather an evolutionary grade consisting of the most basal lepospondyls. Utaherpeton has been proposed as both the most basal lepospondyl and the oldest "microsaur", although more derived lepospondyls are known from earlier in the Carboniferous. However, its position within Lepospondyli remains uncertain due to the incomplete preservation of the only known specimen. The inclusion of Utaherpeton in various phylogenetic analyses has resulted in multiple phylogenies (hypotheses of evolutionary relationships) that are very different from one another, making it a significant taxon in terms of understanding the interrelationships of lepospondyls.

Like Monjurosuchus, it is a small-bodied, lizard-like animal. The webbed feet of Monjurosuchus reflect its aquatic lifestyle. Cteniogenys is known from North America and Europe, while Monjurosuchus is known from China. Lazarussuchus was considered the most basal choristoderan when first described, and hence a late-surviving basal choristodere.

The family Amblycipitidae is a monophyletic group containing four monophyletic genera, Amblyceps, Liobagrus, Nahangbagrus and Xiurenbagrus. It is the most basal sisoroid family and is sister to a clade formed by the remaining families. The genera Amblyceps and Liobagrus are a sister group pair that is, in turn, sister to Xiurenbagrus.

Most protostomes have schizocoelous development, where cells simply fill in the interior of the gastrula to form the mesoderm. In deuterostomes, the mesoderm forms by enterocoelic pouching, through invagination of the endoderm. Yet two of the most basal and ancient protostome phyla, the chaetognatha and priapulida, have deuterostome-like development.

First named in 1956, Millerettidae was a clade containing all reptiles closer to Milleretta rubidgei than to Macroleter poezicus. Millerettids were among the most basal members of the parareptile lineage.Durand, J.F. "Major African Contributions to Palaeozoic and Mesozoic Vertebrate Palaeontology." Journal of African Earth Sciences 43.1-3 (2005): 53–82.

An analysis of a large number of genera suggested that the taxonomy may need revision. Leucocytozoon appears to be basal to most of the Haemosporidia. The genera Heamoproteus and Parahaemaproteus are the next most basal clade. At least one species in the genus Heamoproteus grouped with the main Plasmodium clade.

There are still disagreements as to the scientific classification, name and age of this species. However the body shape of Jianghanichthys differs from that of all Amyzon species. It has been suggested that the family †Jianghanichthyidae, which is the most basal family of the Cypriniformes, be raised to house this species.

Wahlberg & Brower (2008) The Brassolini contain 17 genera in two or three subtribes, depending whether the enigmatic genus Bia is assigned here as the most basal lineage. The other genera are divided into one small and more ancestral subtribe, and a more advanced one that unites the bulk of the genera.

Apsaravis is the most basal bird that possesses an extensor process. This is a bony projection on metacarpal I that develops at the insertion of the m.extensor metacarpi radialis muscle and the propatagial ligaments. This anatomy functions to "automate" extension of the manus during extension of the forelimb in Aves.

Caenorhabditis kamaaina is a species of nematodes in the genus Caenorhabditis. Prior to 2014, it was referred to as C. sp. 15. The type isolate was collected in Kauai, Hawaii. This species is the most basal in the 'Japonica' group, the sister clade to the 'Elegans' group, in the 'Elegans' supergroup.

The sample found in the Syrian is to date the most basal sample of D2. The recent evidence (as also proposed by Haber et al.) suggests that D2 is a highly divergent haplogroup close to the DE split but on the D branch and lacking the M174 mutation possessed by other D lineages.

Zoological Journal of the Linnean Society 151: 377–421. by noting many characters previously thought to be exclusive of Allosauroidea to have a more wider distribution. Also, Zhao et al. in 2010 noted various primitive features of the skeleton suggesting that Monolophosaurus could be one of the most basal tetanuran dinosaurs instead.

The Placozoa are a basal form of marine free-living (non-parasitic) multicellular organism. They are the simplest in structure of all animals. Three genera have been found: the classical Trichoplax adhaerens, Hoilungia hongkongensis, and Polyplacotoma mediterranea, where the last appears most basal. The last two have been found only since 2017.

Cnidaria, which include jellyfish, corals, and sea anemones, are the most basal animals to possess complex eyes. Jellyfish opsins in the rhopalia couple to Gs-proteins raising the intracellular cAMP level. Coral opsins can couple to Gq-proteins and Gc-proteins. Gc-proteins are a subtype of G-proteins specific to cnidarians.

Charassognathus (meaning 'notched jaw') is an extinct genus of Late Permian cynodonts. Described in 2007 from a locality near Fraserburg, South Africa, Charassognathus is the earliest and most basal cynodont. It is known only from the holotype, which dates from the Late Permian Period. The type and only species is C. gracilis.

They reused Porfiri et al. (2018)'s analysis, though corrected some scores and added data from recent studies. The study returned Neovenator to a monophyletic Allosauroidea, and placed megaraptorans as basal non- tyrannosauroid coelurosaurs close to Chilantaisaurus and Gualicho. Murusraptor was also placed as the second-most basal megaraptoran, ahead of Fukuiraptor.

Schizanthus comprises 12 species of annuals and biennials, which make up the monospecific subfamily, Schizanthoideae. This subfamily is the most basal grouping in Solanaceae, and is therefore sister to all higher taxa of the family.Olmstead, R.G. and J.D. Palmer, 1992. A Cholorplast DNA Phylogeny of the Solanaceae: Subfamilial Relationships and Character Evolution.

There is some uncertainty regarding the phylogenetic position of the solenogasters. Traditionally considered to be the most basal molluscan group and the sister group to the Caudofoveata, alternatives to both of these statements have been proposed on various lines of evidence. Indeed, some molecular datasets plot Solenogastres as an outgroup to Mollusca.

Fugusuchus is an extinct genus of erythrosuchid archosauriform. It was one of the earliest and most basal erythrosuchids. The genus is known from a single fossil from the middle Early Triassic Heshankou Formation in Shanxi, China. The partial skeleton consists of an incomplete skull, parts of the right forelimb, and an intercentrum.

The phylogeny of Hamamelidaceae has not been resolved with much certainty, but in one recent molecular phylogenetic study, Exbucklandia and Rhodoleia formed the most basal clade in the family.Susana Magallón. 2007. "From Fossils to Molecules: Phylogeny and the Core Eudicot Floral Groundplan in Hamamelidoideae (Hamamelidaceae, Saxifragales)". Systematic Botany 32(2):317-347.

The chloroplasts characteristically contain chlorophyll a and chlorophyll c, and usually the accessory pigment fucoxanthin, giving them a golden-brown or brownish-green color. Most basal heterokonts are colorless. This suggests that they diverged before the acquisition of chloroplasts within the group. However, fucoxanthin-containing chloroplasts are also found among the haptophytes.

Australidelphia is the superorder that contains roughly three-quarters of all marsupials, including all those native to Australasia and a single species from South America (all other American marsupials are members of the Ameridelphia). Analysis of retrotransposon insertion sites in the nuclear DNA of a variety of marsupials has shown that the South American monito del monte's lineage is the most basal of the superorder. The Australian australidelphians form a clade, for which the name Euaustralidelphia ("true Australidelphia") has been proposed (the branching order within this group is yet to be determined). The study also showed that the most basal of all marsupial orders are the other two South American groups (Didelphimorphia and Paucituberculata, with the former probably branching first).

The study included the Taimyr wolves, the Goyet "dog", the Altai "dog", Beringian wolves, and other ancient specimens. The study found 114 different wolf haplotypes among 314 sequences, with the new haplotypes being found in Siberia and China. The phylogenetic tree resolved into 19 clades that included both modern and ancient wolves, which showed that the most basal clades included the Indian gray wolf and the Himalayan wolf, with a subclade of wolves from China and Mongolia falling within the Himalayan wolf clade. The two most basal North American haplotypes included the Mexican wolf and the Vancouver Island wolf, however the Vancouver Island wolf showed the same haplotype as a dog which indicates admixture, with the dog lineage basal to all extant North American subspecies.

The Brusatte et al.(2010) dataset placed it as the most basal pseudosuchian (although the name "Crurotarsi" was used for the group), less crownward (further from crocodilians) than even the phytosaurs. Nesbitt et al. (2014)'s application of the Nesbitt (2011) dataset placed Nundasuchus more crownward, compared to its position in Brusatte et al.

Gyrodon is a genus of pored mushroom bearing close affinity to the genus Paxillus. Recent molecular research has confirmed this relationship of the two genera as sister taxa, together diverging as one of the most basal lineages in the Boletineae, and sister to the Boletaceae. Gyrodon was circumscribed by German botanist Wilhelm Opatowski in 1836.

The taxon was in 1995 and 2001 assigned to the Hypsilophodontidae. Today this is considered an unnatural paraphyletic group and Gideonmantellia was in 2012 placed in a relatively basal position in the group Ornithopoda. More recently, a 2017 study by Madzia et al. describing the genus Burianosaurus found Gideonmantellia to be the most basal ornithopod.

For a long time, the four species of Calciphilopteris were included in the polyphyletic genus Doryopteris. Molecular phylogenetic studies have shown that Calciphilopteris is the most basal clade in the subfamily Cheilanthoideae. It is thus far removed from Doryopteris palmata, the type species of Doryopteris. Calciphilopteris was described as a new genus in 2010.

The gray fox's dwarf relative, the island fox, is likely descended from mainland gray foxes. These foxes apparently were transported by humans to the islands and from island to island, and are descended from a minimum of 3–4 matrilineal founders. The genus Urocyon is considered to be the most basal of the living canids.

Sauropodomorpha, of which Neosauropoda is a subclade, first arose in the late Triassic. Around 230 million years ago, animals such as Eoraptor, the most basal known member of Dinosauria and also Saurischia, already displayed certain features of the Sauropod group. These derived characters began to distinguish them from Theropoda.Sereno, Paul; Martinez Ricardo; Alcober, Oscar. 2012.

Eriphostoma is an extinct genus of gorgonopsian therapsids known from the Middle Permian (middle Capitanian stage) of Tapinocephalus Assemblage Zone, South Africa. It has one known species, Eriphostoma microdon, and was first named by Robert Broom in 1911. It is the oldest known gorgonopsian and among the smallest and most basal members of the clade.

Nathan Lovejoy's 1996 phylogenetic analysis, based on morphology, found that the yellow stingray is the most basal member of a clade that also contains Pacific Urobatis species and the genus Urotrygon of Central and South America. This finding would render Urobatis polyphyletic, though further study is warranted to elucidate the relationships between these taxa.

Pseudoboletus parasiticus, previously known as Boletus parasiticus and Xerocomus parasiticus, commonly known as the parasitic bolete is a rare Boletaceae mushroom found on earthballs (Scleroderma citrinum). Pseudoboletus parasiticus is one of the early most diverging lineages of the Boletaceae, the lineage of Chalciporus spp and Buchwaldoboletus lignicola is the most basal lineage in the Boletaceae.

"New information on Segisaurus halli, a small theropod dinosaur from the Early Jurassic of Arizona". Journal of Vertebrate Paleontology 25 (4): 835-849 Ezcurra (2012) found Sarcosaurus to be the most basal ceratosaur in a large unpublished analysis.Ezcurra, 2012. Phylogenetic analysis of Late Triassic - Early Jurassic neotheropod dinosaurs: Implications for the early theropod radiation.

This was also a result of an analysis by Victoria Megan Arbour recovering Cedarpelta just above Gastonia, the most basal ankylosaurid in her study. No tail club of Cedarpelta is known, but Arbour stressed that early ankylosaurids might well have lacked a true club.Arbour, Victoria Megan, 2014. Systematics, evolution, and biogeography of the ankylosaurid dinosaurs.

L. Jepson 1930); Eucosmodon kuszmauli ; and Stygimys gratus. Remains were found in Maastrichtian (Upper Cretaceous) - Puercan (Paleocene)-age strata of the Polecat Bench Formation of Wyoming and the Hell Creek Formation of Montana. Some scraps of jaw are known. This species is the most basal member of the genus, with a weight of 300 g.

The costal medial area is quadrangular. The forewing ground colour is light yellow grey and unicolorous in the most basal area, other parts of the forewing are suffused by black and brown areas. The crosslines are untraceable, except for the indistinct subterminal and subterminal lines. The terminal line is well marked by black interneural dots.

The remaining tree was the same as in D'Emic (2012), although Brachiosaurus was collapsed into a polytomy with more derived brachiosaurids. Another phylogeny, Mannion et al. (2017) found similar results to D'Emic (2012) and D'Emic et al. (2016). Europasaurus was the basalmost brachiosaurid, with the "French Bothriospondylus", or Vouivria, as the next most basal brachiosaurid.

Andescynodon is a genus of traversodontid cynodonts from the Middle Triassic of Argentina. Fossils are known from the Cerro de las Cabras and Cacheutá Formations. Andescynodon is one of the most basal traversodontids. Another traversodontid called Rusconiodon has also been identified from the Cerro de las Cabras Formation but is now considered a junior synonym of Andescynodon.

Otocinclus is the most basal genus of the tribe Hypoptopomatini of the subfamily Hypoptopomatinae. However, phylogenetic relationships are currently under study and this genus may eventually be relocated. Its monophyly is supported by seven derived features. O. batmani, O. bororo, O cocama, O. huaorani, O. mariae and O. mura form a monophyletic group within this genus.

Sisoroidea is sister to the Loricarioidea. The monophyly of this superfamily is supported by a number of morphological characters. Amblycipitidae is the most basal family and is sister to the remaining families. Based on morphological data, Erethistidae is the sister group to Aspredinidae, with Sisoridae being the sister group of the clade formed by these two families.

Raranimus is an extinct genus of therapsids of the Middle Permian. It was described in 2009 from a partial skull found in 1998 from the Dashankou locality of the Xidagou Formation, outcropping in the Qilian Mountains of Gansu, China. The genus is the most basal known member of the clade Therapsida, to which the later Mammalia belong.

The relationship between the tribes has recently been well described. Nicandreae is the most basal tribe of the family, placing sister to the other 9 (or by some counts 11) tribes. Datureae lies sister to Nicandreae, Physaleae, Capsiceae, and Solaneae. Solaneae + (Physaleae + Capsiceae) form a well-supported monophyletic group, but the exact branching within the clade remains unclear.

The deep branching of chordate phylogeny has been clarified by chordate genomics."The amphioxus genome and the evolution of the chordate karyotype." Nicholas H. Putnam, et al. Nature 453 1064-1071, (2008) Chordate genomics demonstrates that the Lancelets are the most basal living clade within the chordates, while the Tunicates are the sister clade to the Craniata.

Pediculus humanus Phthiraptera, the lice, includes 5,000 described species divided into 4 suborders. The Amblycera is the most basal group and parasitize birds and mammals. The Ischnocera is the largest suborder and parasitize mostly birds and some groups of mammals. The Rhynchophthirina, the elephant lice, consists of only 3 species that parasitize elephants and wild pigs in Africa.

The stalk-eyed mud crab, Macrophthalmus hirtipes, is a marine large-eyed crab of the family Macrophthalmidae, endemic to New Zealand including Campbell Island. It grows to around shell width. It is either the only species in the subgenus Hemiplax and the most basal species in the genus Macrophthalmus, or the only species in the sister genus Hemiplax.

This study, Mariscano et al.. (2017), agreed that Australerpeton was a rhinesuchid, but considered it the most basal member of the family. They disagree with Eltink et al.'s recognition of short anterior pterygoid branches in multiple genera. According to their analysis, only Australerpeton possessed this trait, the main feature which separates it from the rest of Rhinesuchidae.

This confirms that the genus Cooksonia sensu Lang (1937) is polyphyletic. A core group of five species are placed together, unresolved between the euphyllophytes and the lycophytes. The poorly preserved C. hemisphaerica is placed as the most basal tracheophyte. Two other species, C. crassiparietilis and C. caledonica, are placed in the stem group of the lycophytes.

The type species for this genus is Callichthys pectoralis. The name is derived from the Greek leptos, meaning "thin", the Greek hoplon, meaning "weapon", and the Greek sternon, meaning "chest" or "sternum". Lepthoplosternum is relatively basal among callichthyines, being sister to the clade comprising Megalechis + Dianema + Hoplosternum. Callichthys is the most basal genus in the subfamily.

In: Weishampel DB, Dodson P, Osmólska H, eds. The dinosauria, 2nd edn. Berkeley, CA: University of California Press, 71–110. It may in fact be the most basal coelurosaurian yet known, or may even be close to the common ancestor of the two groups; in any case, it represents one of the oldest definitive tetanuran theropods.

The consensus view in contemporary palaeontology is that the flying theropods, or avialans, are the closest relatives of the deinonychosaurs, which include dromaeosaurids and troodontids. Together, these form a group called Paraves. Some basal members of Deinonychosauria, such as Microraptor, have features which may have enabled them to glide or fly. The most basal deinonychosaurs were very small.

Dinheirosaurus is not extremely well known, and as a consequence, its phylogenetic position is not certain. In 2012 during a redescription of the taxon by Philip Mannion et al., it was recovered, in both cladograms, to be sister species to Supersaurus vivianae and together forming the most basal diplodocines. A 2012 cladogram, published by Mannion et al.

According to Zhu's 1991 redescription of Diandongpetalichthys,Zhu, M. "New information on Diandongpetalichthys (Placodermi: Petalichthyida)." Early vertebrates and related problems of evolutionary biology. Science Press, Beijing (1991): 179-192. that genus represents the most basal petalichthyid known, as it has a comparatively elongated head, and shares certain anatomical features with acanthothoracids and primitive arthrodires such as the actinolepids.

It consists of an incomplete skull and other postcranial fragments. Phylogenetic analysis of this specimen, demonstrates that Sinosaurus is a more derived theropod, and is not the most basal dilophosaurid, as held by Smith et al. A cladogram was identified by Christophe Hendrickx and Octávio Mateus. It placed Sinosaurus and Cryolophosaurus in a polytomy at the base of Tetanurae.

For more than a century, these ferns were considered part of the Davalliaceae. Then starting in the mid-twentieth century they began to be transferred to the Dennstaedtiaceae. Molecular data supported the separation of Lindsaeaceae into its own family, which was proposed in 1970. Lindsaeaceae is considered among the most basal of the families in the order Polypodiales.

Upper side of skull A 2002 phylogenetic analysis found that the genera Pseudopalatus, Mystriosuchus, Redondasaurus and Nicrosaurus are all under the clade Pseudopalatinae. Though, the analysis only contained one non-pseudopalatine phytosaur taxon. If Mystriosuchus and Ebrachosuchus neukami were to be sister taxa, the tree length would be 119. Nicrosaurus is considered the most basal taxon of the clade.

Utaherpeton is an extinct genus of lepospondyl amphibian from the Carboniferous of Utah. It is one of the oldest and possibly one of the most basal ("primitive") known lepospondyls. The genus is monotypic, including only the type species Utaherpeton franklini. Utaherpeton was named in 1991 from the Manning Canyon Shale Formation, which dates to the Mississippian-Pennsylvanian boundary.

Included in the most basal of snake relatives, Pachyophis in contrast does not have evidence of any form of limb preservation. Despite this, they are considered under Pachyophiidae due to their other morphological similarities along with the generas Mesophis and Simoliophis. Only one species has been discovered for the genus Pachyophis. This holotype is known as Pachyophis woodwardi.

Some of the first molecular phylogenetic studies of monocots resolved the Orchidaceae as sister to the astelioid clade of the order Asparagales, but this result never had strong statistical support. It is now known that Orchidaceae is the most basal clade in Asparagales, with the astelioid clade diverging next. (See External links below).Peter F. Stevens (2001 onwards).

Sloth bears lack lower central incisors and use their protusible lips for sucking up the termites on which they feed. The general dental formula for living bears is: . The structure of the larynx of bears appears to be the most basal of the caniforms. They possess air pouches connected to the pharynx which may amplify their vocalizations.

Procynosuchus (Greek: "Before dog crocodile") is an extinct genus of cynodonts from the Late Permian. It is considered to be one of the earliest and most basal cynodonts. It was 60 cm (2 ft) long and seems to have been adapted to a semi-aquatic lifestyle. Remains of Procynosuchus have been found in Germany, Zambia and South Africa.

Hyphalosaurus Monjurosuchus splendens Long considered to be a morphologically conservative group, recent phylogenetic analyses and descriptions of new taxa have revolutionized understanding of this taxon. The order Choristodera comprises two monophyletic groups and three basal taxa. Primitive choristoderes are characterized by small body size, a large, dorsally directed orbit and closed lower temporal fenestrae. Cteniogenys is the most basal choristodere.

Tracing the evolution of these species has been problematic given the scarcity of good fossils. DNA sequences have become the preferred approach to understanding speciation. The order appears to have originated about 420 million years ago during the Silurian. The 39 extant species fall into three families—the Callorhinchids, Rhinochimaerids and Chimaerids with the callorhinchids being the most basal clade.

Valenopsalis is an extinct mammal from the Paleocene of North America (more specifically, Puercan-aged deposits in Wyoming, Montana and Saskatchewan. Originally referred to the genus Catopsalis (C. joyneri), it has more recently been moved to its own genus as the former was understood to be a wastebasket taxon. It is currently considered to be the most basal representative of Taeniolabidoidea.

Ophiacodontidae is an extinct family of early eupelycosaurs from the Carboniferous and Permian. Archaeothyris, and Clepsydrops were among the earliest ophiacodontids, appearing in the Late Carboniferous. Ophiacodontids are among the most basal synapsids, an offshoot of the lineage which includes therapsids and their descendants, the mammals. The group became extinct by the Middle Permian, replaced by anomodonts, theriodonts, and the diapsid reptiles.

Purple anemone (Heteractis magnifica) and resident anemonefish (Amphiprion ocellaris) in East Timor. The species Amphiprion ocellaris belongs to the class Actinopterygii which contains bony Teleost fish and other ray-finned fish. A. ocellaris is the most basal species in the genus Amphiprion which is closely related to the genus Premnas. The species' most closely related ancestor is Amphiprion percula, the Orange clownfish.

Mount with alternate skull reconstruction Epachthosaurus is considered to be the most basal titanosaurian known with procoelous caudal vertebrae. Below is a phylogenetical cladogram showing the position of Epachthosaurus within Titanosauria: The cladogram below follows Mocho et al. (2019), placing Epachthosaurus within Lithostrotia, instead of a basal titanosaur.Mocho P, Páramo A, Escaso F, Marcos-Fernández F, Vidal D, Ortega F. 2019.

Edopoidea is a clade of primitive temnospondyl amphibians including the genus Edops and the family Cochleosauridae. Edopoids are known from the Late Carboniferous and Early Permian of North America and Europe, and the Late Permian of Africa. They are among the most basal temnospondyls, and possess a number of primitive features that were lost in later members of the group.

Compared to the latter it had longer legs and lacked a pierced deltopectoral crest on the humerus. Eoconfuciusornis was assigned to the Confuciusornithidae. It would have been the most basal species known of that group, as reflected by the generic name and in conformation to the age ascribed to it, about six million years older than the specimens of Confuciusornis.

New RHS Dictionary of Gardening. Macmillan .University of British Columbia Botany Photo of the Day, August 31, 2006: Xanthoceras sorbifolia and Aesculus hippocastanum The genus name Xanthoceras (which translates as "yellow horn") is considered to be the most basal member of the family Sapindaceae.Harrington, M. G., Edwards, K. J., Johnson, S. A., Mark W. Chase, M. W., & Gadek, P. A. (2005).

Initially, it was not clear if Kotasaurus represents a true sauropod or a basal sauropodomorph that has to be classified outside Sauropoda. Some paleontologists placed it inside a basal sauropod family called Vulcanodontidae though, together with Barapasaurus and the fragmentary Ohmdenosaurus and Zizhongosaurus. This grouping is now recognized to be paraphyletic. Today Kotasaurus is recognized as one of the most basal sauropods known.

Claudiosaurus (claud is Latin for "lameness" and saurus means "lizard") is an extinct genus of diapsid reptiles from the Permian Sakamena Formation of the Morondava Basin, Madagascar. Claudiosaurus is the most basal neodiapsid. Claudiosarus are found to be a sister group of the Neodiapsida. The pattern of the vertebrate, girle, and limbs indicates that Claudiosaurus and Thadeosaurus share a common ancestor.

Chenanisuchus ("Chenane crocodile") is a genus of dyrosaurid crocodyliform from the Late Cretaceous of Mali and the Late Palaeocene of Sidi Chenane in Morocco. It was described in 2005, after expeditions uncovered it in 2000. The type species is C. lateroculi ("lateralis", lateral; "oculi", eyes), in reference to the laterally facing eyes. Currently, Chenanisuchus is the most basal known dyrosaurid.

However, some scholars (such as Ciochon, Holdroyd and Gunnell) suggest that their similarities to simians is the result of convergent evolution and that they should instead be considered Adapiformes. According to Beard et al., Siamopithecus is the most basal form of amphipithecid. They vary in size from 6–7 kg (Siamopithecus and Pondaungia), to 1–2 kg (Myanmarpithecus), with Bugtipithecus being even smaller.

Of the five orders, hyraxes are the most basal, followed by embrithopods; the remaining orders (sirenians, desmostylians, and elephants) are more closely interrelated. These latter three are grouped as the Tethytheria, because it is believed that their common ancestors lived on the shores of the prehistoric Tethys Sea; however, recent myoglobin studies indicate that even Hyracoidea had an aquatic ancestor.

The tribe Rhinelepini has an interesting biogeography and reveal information about the aquatic systems of South America. There is a split between the species that inhabit Amazon and those that inhabit the eastern river systems. Pseudorinelepis, the most basal group, is found only in the Amazon basin. Pogonopoma, is found in the Mucuri, Paraíba do Sul, and Uruguay River systems in southeastern Brazil.

Struthiosaurus (Latin struthio = ostrich + Greek sauros = lizard) is one of the smallest known and most basal genera of nodosaurid dinosaurs, from the Late Cretaceous period (Santonian-Maastrichtian) of Austria, Romania, France and Hungary in Europe.Struthiosaurus in The Dinosaur Encyclopaedia at Dino Russ's Lair It was protected by body armour. Although estimates of its length vary, it may have been as small as long.

The sacrum consisted of three to ten sacral vertebrae. They too, could be connected via a supraneural plate that, however, would not contact the notarium. The shoulder girdle connected to the notarium The tails of pterosaurs were always rather slender. This means that the caudofemoralis retractor muscle which in most basal Archosauria provides the main propulsive force for the hindlimb, was relatively unimportant.

Abietinae was found to be very nearly monophyletic, and so retained. It further resolved into four subclades, so Thiele and Ladiges split it into four subseries. Banksia sphaerocarpa appeared in the second of these, initially called the ' grossa clade' for its most basal member. As with George's classification, B. grossa and B. micrantha emerged as close relatives of B. sphaerocarpa.

The dorsal vertebrae of titanosaurs show multiple derived features among sauropods. Similarly to the Rebbachisauridae, titanosaurs lost the , a set of surfaces between vertebrae that prevent additional rotation of the bones. Andesaurus, one of the most basal titanosaurs, shows a normal hyposphene. The same area is reduced in Argentinosaurus to only two ridges, and is fully absent in taxa like Opisthocoelicaudia and Saltasaurus.

The Biblidinae are sometimes merged here. The present subfamily is also sometimes included as a tribe Limenitidini in the Nymphalinae. But in fact, their closest living relatives seem to be the Heliconiinae.Wahlberg & Brower (2007a,b) The Limenitidinae are traditionally divided into four tribes, of which the Parthenini are the most basal lineage and the others form a close-knit and more apomorphic radiation.

The species that survived late into the Cretaceous were characterized by stocky, wide- gauged posture, most notably the highly derived saltasaurines. Also under Macronaria are Camarasaurus, Brachiosaurus, and Titanosauria. Camarasauromorpha is the most basal group of Macronaria. The cladogram below follows José Luis Barco Rodríguez (2010). The cladogram below follows José L. Carballido, Oliver W. M. Rauhut, Diego Pol and Leonardo Salgado (2011).

The Dysderoidea are a clade or superfamily of araneomorph spiders. The monophyly of the group, initially consisting of the four families Dysderidae, Oonopidae, Orsolobidae and Segestriidae, has consistently been recovered in phylogenetic studies. In 2014, a new family, Trogloraptoridae, was created for a recently discovered species Trogloraptor marchingtoni. It was suggested that Trogloraptoridae may be the most basal member of the Dysderoidea clade.

The monophyly of the group has been confirmed in morphological studies. One hypothesis for the relationships of the four families is shown in the following cladogram: Earlier studies agree in placing the Sicariidae as the most basal family, but reverse the positions of Drymusidae and Scytodidae. Scytodoidea is placed within the haplogyne clade of araneomorph spiders, as one of the more derived clades.

Proterosuchus is an early member of Archosauriformes, which also contains crocodilians, pterosaurs, and dinosaurs, including birds. It is the type genus of Proterosuchidae, which also contains the genus Archosaurus. Proterosuchidae is, by definition, the most basal clade of archosauriforms, as Archosauriformes is defined based on their phylogenetic position. Under pre-cladistic taxonomy, Proterosuchus was classified in the order Thecodontia and suborder Proterosuchia.

Bothriceps is an extinct genus of stereospondyl temnospondyl. It is a member of the infraorder Trematosauria and is the most basal brachyopomorph known. It is one of the only brachyopomorph that lies outside the superfamily Brachyopoidea, which includes the families Brachyopidae and Chigutisauridae. It shares several similarities to Keratobrachyops, another basal brachyopomorph, and may be closely related to or even synonymous with it.

Biarmosuchia is an extinct clade of non-mammalian synapsids from the Permian. Biarmosuchians are the most basal group of the therapsids. They were moderately-sized, lightly-built carnivores, intermediate in form between basal sphenacodont "pelycosaurs" and more advanced therapsids. Biarmosuchians were rare components of Permian ecosystems, and the majority of species belong to the clade Burnetiamorpha, which are characterized by elaborate cranial ornamentation.

Leninia is one of the latest-living ophthalmosaurines, and also one of the most basal. Despite this, it still had the very large sclerotic ring and aperture, suggesting that this was one of the most basal characteristics of ophthalmosaurines and that they were all deep-diving, remaining conservative in this ecological niche during the entire time period that they existed. The absolute size of Leninia's sclerotic ring is among the largest known in ichthyosaurs, with only Baptanodon ('Ophthalmosaurus natans') and the giant Temnodontosaurus exceeding it. As all the ophthalmosaurines had this kind of structure, and were more similar in eye structure than the platypterygines, this suggests that they did not diversify in the same way that the platypterygines did but stayed similar as deep divers, possibly as they were so specialised for deep diving that they were outcompeted in other niches.

Sphaerotheriida is divided into four families whose distributions do not overlap: Procyliosomatidae, Zephroniidae, Sphaerotheriidae and Arthrosphaeridae. The most basal family, Procyliosomatidae, lives in Australia and New Zealand. The Zephroniidae (synonym Sphaeropoeidae) occurs in southeast Asia from the Himalayas and China south and east to Sulawesi and inhabits some Philippines islands. The family Sphaerotheriidae only occurs in South Africa with isolated populations in Zimbabwe and Malawi (probably introduced).

The tooth-billed pigeon (Didunculus strigirostris), also known as the manumea, is a large pigeon found only in Samoa. It is the only living species of genus Didunculus. Phylogenetic studies indicate that it is the most basal living member of the clade Columbidae. A related extinct species, the Tongan tooth- billed pigeon (Didunculus placopedetes), is only known from subfossil remains in several archeological sites in Tonga.

The most basal anomodont therapsid and the primacy of Gondwana in the evolution of the anomodonts. Proc. R. Soc. Lond. B 266:331–337. Suminia getmanovi is the only defined species within the genus and it is known for specializations in teeth for effective, functional oral processing of plant material as well as being one of the first species with a proposed arboreal lifestyle.

In 2014, Eric Pasquet et al. published a phylogeny confirming the relationship between the Micrositta species, and found the Yunnan nuthatch to be the most basal species of the group. The canadensis group of species includes six species, which are also those of what is sometimes treated as the subgenus Sitta (Micrositta),Erik Matthysen (ill. David Quinn), The Nuthatches, A&C; Black, 2010, 355 p.

Several other arrangements of these orders have been proposed in the past, and the above tree is only a well-favored proposal. Although it is known that Scandentia is one of the most basal Euarchontoglire clades, the exact phylogenetic position is not yet considered resolved: It may be a sister of Glires, Primatomorpha, or Dermoptera, or separate from and sister to all other Euarchontoglires.

One recent analysis found the family Coeluridae, including the Late Jurassic North American genera Coelurus and Tanycolagreus, to be the sister group of Tyrannosauroidea. The most basal tyrannosauroid known from complete skeletal remains is Guanlong, a representative of the family Proceratosauridae. Other early taxa include Stokesosaurus and Aviatyrannis, known from far less complete material. The better-known Dilong is considered slightly more derived than Guanlong and Stokesosaurus.

The family Branchiosauridae includes the genera Branchiosaurus, Apateon, Melanerpeton, Leptorophus and Schoenfelderpeton. The stratigraphically oldest genus is Branchiosaurus, with its only well-known species being B. salamandroides, and forms the most basal node of Branchiosauridae. The post-Branchiosaurus branchiosaurids fall into either the Melanerpeton-clade or the Apateon clade. Within the morphogenically more diverse Melanerpeton-clade, the genera Schoenfelderpeton and Leptorophus are sister groups.

In that year, Gentry published a taxonomic revision of Tabebuia in Flora Neotropica. He divided Tabebuia into 10 species groups, including all of the species now placed in Roseodendron and Handroanthus. His group 1 corresponds to Roseodendron. In 2007, a phylogenetic analysis of DNA sequences resolved Roseodendron as one member of a tetratomy that is sister to Sparattosperma, the most basal clade in the Tabebuia alliance.

The subgenus Castaneides was created to contain all eastern species of Aneides, with caryaensis being the most basal member of the complex. Castaneides diverged from the Aneides hardii lineage between 27.2 and 32.3 million years ago. Members of Castaneides are the only salamanders in North America with green markings. Due also to their hyper-specific habitat, they are almost unmistakable when found in the field.

Conant et al. in 1996, concluded on molecular cpDNA and morphological evidence that a system of three clades – Alsophila, Cyathea and Sphaeropteris was the most accurate reflection of evolutionary lineages within the Cyatheaceae, Alsophila being the most basal and Cyathea and Sphaeropteris derived sister groups. In the Pteridophyte Phylogeny Group classification of 2016 (PPG I), these are accepted as separate genera, Alsophila, Cyathea and Sphaeropteris.

These are among the most basal lineages of living cyprinids. Other "rasborines" are apparently distributed across the diverse lineages of the family. The validity and circumscription of proposed subfamilies like the Labeoninae or Squaliobarbinae also remain doubtful, although the latter do appear to correspond to a distinct lineage. The sometimes-seen grouping of the large-headed carps (Hypophthalmichthyinae) with Xenocypris, though, seems quite in error.

Prototaria is an extinct genus of pinniped that lived approximately 15.97 to 13.65 mya during the Middle Miocene in what is now Japan. It belonged to the family Odobenidae, the only extant species of which is the walrus. Members of the genus Prototaria are believed to be the most basal imagotariine pinnipeds. Unlike their closest living relative, the walrus, members of Prototaria were primarily piscivorous carnivores.

Albertaceratops is known from a single complete skull (TMP.2001.26.1) found in August 2001 and skull and postcranial fragments. A phylogenetic analysis carried out by its describer, Michael J. Ryan, found it to be the most basal centrosaurine. Additional specimens were reported from a bonebed in the Judith River Formation of Montana, which is equivalent to the Oldman Formation and differentiated only by the Canada–US border.

Natural History Museum Bern. E. patteni was originally described as a species of the genus Hughmilleria, but it was considered different enough to represent a new separate genus in 2008. Eysyslopterus is considered to be the most basal adelophthalmid genus due to the position of its eyes. These are placed closer to the margin than to the ocelli, in contrast to any other adelopthalmid.

Micropterigidae, Agathiphagidae and Heterobathmiidae are the oldest and most basal lineages of Lepidoptera. The adults of these families do not have the curled tongue or proboscis, that are found in most members of the order, but instead have chewing mandibles adapted for a special diet. Micropterigidae larvae feed on leaves, fungi, or liverworts (much like the Trichoptera). Adult Micropterigidae chew the pollen or spores of ferns.

They have been found in South America, Europe, North America, Asia, Australia, and Africa. The temporal range of Eusauropoda ranges from the early Jurassic to the Latest Cretaceous periods. The most basal forms of eusauropods are not well known and because the cranial material for the Vulcanodon is not available, and the distribution of some of these shared derived traits that distinguish Eusauropoda is still completely clear.

GRs are predominantly bound when humans wake from sleep or experience stress. Therefore, GRs arbitrate most of the stress effects of cortisol and glucocorticoids in other species, while MRs control most basal effects. Often, cortisol and GR effects oppose the cortisol and MR effects. This leads many researchers to speculate that early childhood (and adult) stress resilience and weakness entail the ratio of MR to GR activation.

Nuttalliella namaqua is a tick found in southern Africa from Tanzania to Namibia and South Africa, which is placed in its own family, Nuttalliellidae. It can be distinguished from ixodid ticks and argasid ticks by a combination of characteristics including the position of the stigmata, lack of setae, strongly corrugated integument, and form of the fenestrated plates. It is the most basal lineage of ticks.

Ranunculales is an order of flowering plants. Of necessity it contains the family Ranunculaceae, the buttercup family, because the name of the order is based on the name of a genus in that family. Ranunculales belongs to a paraphyletic group known as the basal eudicots. It is the most basal clade in this group; in other words, it is sister to the remaining eudicots.

Restoration of an Eomaia feeding on a Cretophasmomima Cretophasmomima is an extinct genus of stem-stick insect from the Cretaceous of Eurasia and is one of the oldest and most basal stick insects known. The type species, Cretophasmomima vitimica, was described in 1985 from the Aptian aged Zaza Formation in Russia.S. A. Kuzmina. 1985. New Orthoptera of the Family Phasmomimidae from the Lower Cretaceous in Transbaikalia.

Specimen IVPP V14322 Details of specimen BMNHC Ph798, the skull is partially covered by fibula and tibia. In 2002 Sinovenator was placed in the Troodontidae. Sinovenator is a basal or "primitive" troodontid, and shares features with the most basal dromaeosaurids and Avialae. It thus was one of the first fossil specimens conclusively demonstrating the close relation of these three groups in the overarching Paraves.

Largest sizes of the type genera of each of the pterygotioid families, Pterygotus, Slimonia and Hughmilleria, compared to a human. Though the Pterygotidae are accepted to clearly represent the most derived group within the pterygotioid superfamily, there has been an ongoing debate on whether the hughmilleriids or the slimonids are the most closely related to the pterygotids, and thus also which of the two families is the most basal. This debate was resolved with the description of Ciurcopterus, a primitive pterygotid that clearly combines features of Slimonia (especially within the appendages) and of more derived pterygotid eurypterids, revealing that Slimonidae was the closest sister-group of the Pterygotidae. The lack of ornamentation in the telson of Hughmilleria, combined with the fact that the genus shares certain characteristics with basal adelophthalmids (in particular the triangular anterior margin of the carapace), places it as the most basal genus in the superfamily.

The most basal or root level existing strains of the Yersinia pestis as a whole species are found in Qinghai, China. After samples of DNA from Yersinia pestis were isolated from skeletons of Justinian plague victims in Germany, it was found that modern strains currently found in the Tian Shan mountain range system are most basal known in comparison with the Justinian plague strain. Additionally, a skeleton found in Tian Shan dating to around 180 AD and identified as an "early Hun" was found to contain DNA from Yersinia pestis closely related to the Tian Shan strain basal ancestor of the Justinian plague strain German samples. This finding suggests that the expansion of nomadic peoples who moved across the Eurasian steppe, such as the Xiongnu and the later Huns, had a role in spreading plague to West Eurasia from an origin in Central Asia.

A more recent study in 2006 found Shartegosuchidae to be the most basal clade of mesosuchians. A phylogenetic analysis found the family to be monophyletic, meaning that it forms a true clade with a common ancestor from which only shartegosuchids are derived. "Fruitachampsa" was found to be outside Shartegosuchidae, but was the sister taxon of the family. This means that it is more closely related to Shartegosuchidae than any other crocodyliform.

In contrast to the previous analysis, You and Dodson find Chaoyangsaurus to be the most basal neoceratopsian, more derived than Psittacosaurus, while Leptoceratopsidae, not Protoceratopsidae, is recovered as the sister group of Ceratopsidae. This study includes Auroraceratops, but lacks seven taxa found in Xu and Makovicky's work, so it is unclear how comparable the two studies are. Asiaceratops and Turanoceratops are each considered nomina dubia and not included.

Rhinatrematidae, the family of Neotropical tailed caecilians, American tailed caecilians or beaked caecilians, are found in the equatorial countries of South America. They are usually regarded as the most basal of the caecilian families, with numerous characteristics lacking in the other groups. For example, they still possess tails, and their mouths are not recessed on the underside of their heads. They lay their eggs in cavities in the soil.

The origin of this population is unknown. It might have arisen through hybridisation, or it may be a transitional or even ancestral form. Finally, biogeographical factors suggest that B. ilicifolia would be the most basal of the three species: it occurs in the High Rainfall Zone where relictual species are most common, whereas the others are restricted to the Transitional Rainfall Zone, where more recently evolved species are most common.

The origin of this population is unknown: it might have arisen through hybridisation, or it may be a transitional or even ancestral form. Finally, biogeographical factors suggest that B. ilicifolia would be the most basal of the three species: it occurs in the High Rainfall Zone where relictual species are most common, whereas the others are restricted to the Transitional Rainfall Zone, where more recently evolved species are most common.

Lumkuia is an extinct genus of probainognathian cynodonts. It is the earliest and most basal known member of Probainognathia, with fossils being found from the Cynognathus Assemblage Zone of the Beaufort Group in the South African Karoo Basin that date back to the early Middle Triassic. Lumkuia is not as common as other cynodonts from the same locality such as Diademodon and Trirachodon.Fernando Abdala, P. John Hancox and Johann Neveling (2005).

The concept is now considered redundant, and the clade Bullatosauria is now viewed as synonymous with Maniraptoriformes. In 2002, Gregory S. Paul named an apomorphy-based clade Avepectora, defined to include all theropods with a bird-like arrangement of the pectoral bones, where the angled shoulder girdle (coracoids) come in contact with the breastbone (sternum). According to Paul, ornithomimosaurs are the most basal members of this group.Paul, G.S. (2002).

The latest recognized member is the African golden wolf (C. anthus), which was once thought to be an African branch of the golden jackal. As they possess 78 chromosomes, all members of the genus Canis are karyologically indistinguishable from each other, and from the dhole and the African hunting dog. The two African jackals are shown to be the most basal members of this clade, indicating the clade's origin from Africa.

Legs of Kotasaurus Kotasaurus is one of the most basal sauropods known. The general body plan was that of a typical sauropod, but in several basal (plesiomorphic) features it resembles prosauropods. Like all sauropods, Kotasaurus was an obligate quadruped, while prosauropods were primitively bipedal. The body length is estimated at roughly nine meters, with a weight of 2.5 tonnes, and therefore already comparable with that of later sauropods.

Arboroharamiya belongs to a clade or evolutionary grouping called Mammaliaformes, which includes mammals and their closest extinct relatives from the Triassic and Jurassic periods. Within Mammaliaformes, Arboroharamiya falls within the clade Haramiyida. Haramiyidans have been known since the 1840s, but only from fossilized teeth and a single partial lower jaw. However, several features of the teeth have shown for many years that haramiyidans are among the most basal of mammaliaforms.

In 2001, Lisa Rosenberger published a phylogenetic analysis of 14 Dasyatis species, based on morphology. The common stingray was reported to be the most basal member of the genus, other than the bluespotted stingray (D. kuhlii) and pelagic stingray (D. violacea). However, D. violacea has generally been recognized as belonging to its own genus Pteroplatytrygon, and recently D. kuhlii has also been placed in a different genus, Neotrygon.

Casea represents one of the first large and highly successful herbivores among terrestrial reptiles. Among vertebrates this feeding strategy can be subdivided into many categories, including folivory, frugivory, granivory but among early terrestrial vertebrates, it is feeding on leaves, stems, roots and rhizomes. Herbivorous use massive crushing dentition on the palate and mandibles. Caseids belong to the most basal clade of synapside, the Caseasuria, which also includes the small carnivorous eothrydids.

Alsophila deckenii, synonym Cyathea deckenii, is a species of tree fern native to the Democratic Republic of the Congo, Tanzania and Mozambique, where it grows in wet forest at an altitude of 1350–2300 m. The trunk is erect and up to 10 m tall. Fronds are bipinnate and 2–3 m long. Characteristically of this species, the most basal one or two pairs of pinnae are reduced.

In particular, this study revealed that Aralosaurus had a hollow bony structure located far in front of the orbits, which communicated with the respiratory tract. This structure being broken at its base, its shape and size unfortunately remains undetermined. More recently, Aralosaurus has been identified as the most basal Lambeosaurinae, and placed with its close relative Canardia from the upper Maastrichtian of France in the new clade of Aralosaurini.

In 2001, Ji Qiang suggested an alternative position as the sister taxon of the Ornithothoraces. In 2002 Ji's hypothesis was confirmed by a cladistic analysis by Chiappe, who defined a new group: the Pygostylia of which Confuciusornis is by definition the most basal member.L. M. Chiappe (2002) "Basal bird phylogeny: problems and solutions". In: L. M. Chiappe and L. M. Witmer (eds.), Mesozoic Birds: Above the Heads of Dinosaurs.

Xyelidae represent the most basal lineage of Hymenoptera and very likely the sister taxon of all other extant Hymenoptera. This assertion is supported by phylogenetic analyses of both morphological characters and DNA sequences.Sharkey, M.J., Carpenter, J.M., Vilhelmsen, L., Heraty, J., Liljeblad, J., Dowling, A.P.G., Schulmeister, S., Murray, D., Deans, A.R., Ronquist, F., Krogmann, L., Wheeler, W.C. 2012: Phylogenetic relationships among superfamilies of Hymenoptera. Cladistics 28 (2012) 80-112.

Rambutan fruits The Sapindaceae are related to the Rutaceae, and both are usually placed in an order Sapindales or Rutales, depending on whether they are kept separate and which name is used for the order. The most basal member appears to be Xanthoceras. Some authors maintain some or all of Hippocastanaceae and Aceraceae, although this may result in paraphyly. The former Ptaeroxylaceae, now placed in Rutaceae, were sometimes placed in Sapindaceae.

Meat-eater ants feeding on a cicada: social ants cooperate and collectively gather food Not all ants have the same kind of societies. The Australian bulldog ants are among the biggest and most basal of ants. Like virtually all ants, they are eusocial, but their social behaviour is poorly developed compared to other species. Each individual hunts alone, using her large eyes instead of chemical senses to find prey.

Plagiaulacida is a group of extinct multituberculate mammals. Multituberculates were among the most common mammals of the Mesozoic, "the age of the dinosaurs". Plagiaulacids, an informal suborder, are the most basal of this order, and ranged from the Middle Jurassic Period to the Lower Cretaceous Period of the northern hemisphere. Kielan-Jaworowska and Hurum (2001) divides “Plagiaulacida” into three informal lineages, the paulchoffatiids, the plagiaulicids, and the allodontids.

So do the three most basal clades of Sauvagesieae, namely Blastemanthus, Fleurydora, and a clade of four genera that have five carpels and many ovules per carpel (Godoya, Rhytidanthera, Krukoviella, and Cespedesia). Poecilandra has poricidal anther dehiscence, but in its sister genus, Wallacea, the anthers open by longitudinal slits. In the rest of Sauvagesieae, anther dehiscence is various. In Schuurmansia, Schuurmansiella, and Adenarake, the anther dehiscence is apically longicidal.

The most basal genus, Brocchinia, is endemic to the Guiana Shield, and is placed as the sister group to the remaining genera in the family. The subfamilies Navioideae and Lindmanioideae are endemic to the Guiana Shield as well. The West African species Pitcairnia feliciana is the only bromeliad not endemic to the Americas, and is thought to have reached Africa via long-distance dispersal about 12 million years ago.

Restoration of H. socialis. Hughmilleria is the most basal (primitive) known member of the Pterygotioidea. It was a small-sized eurypterid, with the largest specimen measuring 20 cm (8 in), being surpassed by other members of its superfamily, such as Slimonia acuminata, which measured 100 cm (39 in) in length, and Pterygotus grandidentatus, which could reach 1.75 meters (5 ft 8 in).Lamsdell, James C.; Braddy, Simon J. (2009-10-14).

C. elegans adult with GFP coding sequence inserted into a histone-encoding gene by Cas9-triggered homologous recombination As of 2014, C. elegans is the most basal species in the 'Elegans' group (10 species) of the 'Elegans' supergroup (17 species) in phylogenetic studies. It forms a branch of its own distinct to any other species of the group. Tc1 transposon is a DNA transposon active in C. elegans.

Hopson and Barghusen in 1986, who provided the first cladistic study of the Therapsida, coined the term Tapinocephalia for herbivorous dinocephalians, as opposed to the "Anteosauria" for the carnivorous forms. They suggested that Estemmenosuchids are very early/primitive members of the Tapinocephalia. However Thomas Kemp (1982) and Gillian King (1988) argue instead that the Estemmenosuchidae are the most basal Dinocephalia, being more primitive than both the Anteosauria and the Tapinocephalia.

Restoration Eodromaeus is regarded as one of the earliest members of Theropoda, the group that includes the carnivorous dinosaurs. The discovery of Eodromaeus lead some to believe that Eoraptor (typically regarded as a theropod) likely represented one of the most basal sauropodomorphs, the group that includes animals like Apatosaurus. This has since been questioned however, with Bergman and Sues reclaiming Eoraptor as a theropod, like Eodromaeus.Bergman D.S., Sues H-D.

Andescynodon is one of the most basal members of Traversodontidae, a group of cynodonts that was common in South America during the Triassic. Pascualgnathus is a very close relative of Andescynodon but can be distinguished by the greater amount of incisor and postcanine teeth. While Pascualgnathus has three incisors on each side of the upper jaw, while Andescynodon has four (a primitive feature for a traversodontid). Andescynodon also has more postcanine teeth than Pascualgnathus.

The name alludes to the film Crouching Tiger, Hidden Dragon. The specific name progenitor means ancestor or founder of a family in Latin, and refers to the animal's status as the most basal member of the Pterodactyloidea. The holotype, IVPP V18184, was uncovered in a layer of the Shishugou Formation dating from the Callovian–Oxfordian and having a minimum age of 161 million years. It consists of a partial skeleton lacking the skull.

There is no known fossil record of Crassulaceae. The Crassulaceae family evolved approximately 100 million years ago (mya) in southern Africa with the two most basal phylogenetic branches (Crassula, Kalanchoe) representing the predominantly southern African members. Divergence times are shown in Cladogram III. The family had a gradual evolution, with a basal split between Crassuloideae and the rest of the family (Kalanchoideae, Sempervivoideae) at 82 mya, and Sempervivoideae splitting from Kalanchoideae at 71 mya.

The Euclid, which has a maximum thickness of , extends from Independence, Ohio northeast to Willoughby, Ohio, and is part of the most basal member of the Bedford Shale. An extremely large sandstone lens is the Second Berea. Located in Athens, Gallia, Meigs, Morgan, and Muskingum counties, this sandstone body is long and wide. Originally known as the "stray gas sand", it was originally a large sandbar east of what became the Red Bedford Delta.

Owing to its early date, it has since its discovery been considered ancestral to later aïstopods, and more recent cladistic research (Anderson et al. 2003) confirms its position as the most basal (primitive) aistopod. A 2017 cladistic analysis incorporated new data on Lethiscus found all aïstopods, including Lethiscus, to be stem- tetrapods, rendering Lepospondyli polyphyletic.Jason D. Pardo, Matt Szostakiwskyj, Per E. Ahlberg & Jason S. Anderson (2017) Hidden morphological diversity among early tetrapods.

The rear edge of the sternum has two pairs of thin rod-like structures. Although these structures are known in all but the most basal enantiornitheans, only IVPP 21711 has the inner pair extend the same distance as the outer pair. On the other hand, the V-shaped xiphoid region is similar to basal enantiornitheans such as Protopteryx and pengornithids. The forelimb is rather short, with a robust humerus possessing enantiornithean features.

The Tarsophlebiidae is an extinct family of medium-sized fossil odonates from the Upper Jurassic and Lower Cretaceous period of Eurasia. They are either the most basal member of the damsel-dragonfly grade ("anisozygopteres") within the stem group of Anisoptera, or the sister group of all Recent odonates. They are characterized by the basally open discoidal cell in both pairs of wings, very long legs, paddle-shaped male cerci, and a hypertrophied ovipositor in females.

The most basal theropods had five digits in the hand. Along the lineage that led to birds the number of digits in the hand decreased; by the emergence of the group Tetanurae, which includes birds, two digits had disappeared from the hand, leaving three. Traditionally, it has been hypothesized that the digits lost were the two outermost digits, i.e. digits IV and V, in a process known as Lateral Digit Reduction (LDR).

Like the other butterflyfishes with angular yellow bodíes with black eyestripes and (except in the present species) a single differently-colored patch, it belongs in the subgenus Tetrachaetodon. Among this group it seems to be the most basal living species. If Chaetodon is split up, this subgenus would be placed in Megaprotodon. (2007): Molecular phylogenetics of the butterflyfishes (Chaetodontidae): Taxonomy and biogeography of a global coral reef fish family. Mol. Phylogenet. Evol.

A phylogenetic analysis published along with its first description showed that haramiyidans originated before the appearance of true mammals, but an accompanying description of the haramiyidan Arboroharamiya in the same issue of Nature indicated that haramyidans were true mammals. If haramiyidans are not mammals, Megaconus would be one of the most basal ("primitive") mammaliaforms to possess fur, and an indicator that fur evolved in the ancestors of mammals and not the mammals themselves.

Aurornis is an extinct genus of anchiornithid theropod dinosaurs from the Jurassic period of China. The genus Aurornis contains a single known species, Aurornis xui (). Aurornis xui may be the most basal ("primitive") avialan dinosaur known to date, and it is one of the earliest avialans found to date. The fossil evidence for the animal pre-dates that of Archaeopteryx lithographica, often considered the earliest bird species, by about 10 million years.

Rücklin (2011), on the other hand, places Pachyosteus as the most basal selenosteid, then groups the American genera (with Selenosteus grouped as the sister taxon of Gymnotrachelus and Stenosteus) as being the sister group of the remaining European/Kellwasserkalk genera, plus Draconichthys. Some experts imply that Selenosteidae is paraphyletic, as the genus Rhinosteus is often depicted in arthrodire cladograms as being the sister taxon to the Dinichthyloidea taxa Dinichthys (ne "Dinichthyidae"), Gorgonichthys, Heintzichthys, and Hadrosteidae.

This suggests that A-L1085 lineages arrived in Southern Africa from elsewhere. The two most basal lineages of Haplogroup A-L1085, A-V148 and A-P305, have been detected in West Africa, Northwest Africa and Central Africa. Cruciani et al. 2011 suggests that these lineages may have emerged somewhere in between Central and Northwest Africa, though such an interpretation is still preliminary due to the incomplete geographic coverage of African y-chromosomes.

These specimens come from the Cistecephalus Assemblage Zone of the Karoo Basin. Broom attributed the back portion of a third skull to Lycaenodon, but subsequent examiners considered it to belong to a gorgonopsian or dinocephalian and not a biarmosuchian. Most of the distinguishing features of Lycaenodon come from its palate. As a member of Biarmosuchia, the most basal group of therapsids, Lycaenodon shares many features with earlier and less mammal-like synapsids like Dimetrodon.

Restoration of an Alvarezsaurus calvoi skeleton Life restoration of Shuvuuia deserti Turner et al. (2007) place the alvarezsaurs as the most basal group in the Maniraptora, one step more derived than Ornitholestes and two more derived than the Ornithomimosauria. The alvarezsaurs are more primitive than the Oviraptorosauria. Novas' 1996 description of Patagonykus, demonstrated that it was a link between the more primitive (basal) Alvarezsaurus and the more advanced (derived) Mononykus, and reinforced their monophyly.

Alsophila schliebenii, synonym Cyathea fadenii, is a species of tree fern endemic to the Uluguru Mountains in Tanzania, where it grows on exposed ridges and on the upper edge of montane forest at an altitude of 1700–2100 m. The trunk is erect, up to 4 m tall and 3–5 cm in diameter. Fronds are bipinnate. Characteristically of this species, the most basal pair of pinnae are reduced, often to veins alone.

Alagomyidae is a family of rodents known from the late Paleocene and early Eocene of Asia and North America (McKenna and Bell, 1997). Alagomyids have been identified as the most basal rodents, lying outside the common ancestry of living forms (Meng et al., 1994). Because of their phylogenetic position and their conservative dental morphology, alagomyids have played a key role in investigations of the origins and relationships of rodents (Meng et al.

Cheirolepis ('hand fin') is an extinct genus of ray-finned fish that lived in the Devonian period of Europe and North America. It is the only genus yet known within the family Cheirolepidae and the order Cheirolepiformes. It was among the most basal of the Devonian actinopterygians and is considered the first to possess the "standard" dermal cranial bones seen in later actinopterygians. Cheirolepis was a predatory freshwater and estuarine animal about long.

The Allodontid line may be a superfamily, Allodontoidea. Both allodontids and paulchoffatiids (below) were among the most basal of the plagiaulacids. The Allodontid line contains: The family Allodontidae is known from two genera from the Upper Jurassic Morrison Formation of North America. The family Zofiabaataridae contains a single genus, Zofiabaatar and is also from the Morrison Formation. The affinities of a further Morrison Formation genus, Glirodon, are unclear, but it’s also within the Allodontid line.

The name sometimes appears as Vitidaceae, but Vitaceae is a conserved name and therefore has priority over both Vitidaceae and another name sometimes found in the older literature, Ampelidaceae. In the APG III system (2009) onwards, the family is placed in its own order, Vitales. Molecular phylogenetic studies place the Vitales as the most basal clade in the rosids. In the Cronquist system, the family was placed near the family Rhamnaceae in order Rhamnales.

This was already accepted by Stocker and Butler (2013). Although M. jablonskiae is known from an incomplete specimen, it can be diagnosed by at least one autapomorphy and a unique suite of traits, and it includes a well-preserved braincase, which is rarely preserved or described in detail for most phytosaur specimens. A phylogenetic analysis of pseudopalatine phytosaurs performed by Parker and Irmis (2006) found the species to be the most basal species of "Pseudopalatus".

Santanichthys diasii is the only species within the genus Santanichthys. It is classified in the order Characiformes, an order that includes the tetras. Analysis of its morphological characters, including the presence of enlarged lagenar capsules has placed it as one of the most basal characiforms. This, combined with the Early Cretaceous origin of these specimens, makes Santanichthys the earliest known otophysan; The next characiforms up the fossil record date from the Late Cretaceous period already.

The Straight Cliffs Formation was deposited in a variety of sub- environments that varied through time as the relative sea level of the Western Interior Seaway changed. The most basal member, the Tibbet Canyon, was deposited on the edge of the Greenhorn Seaway. The Tibbet Canyon preserves the shoreface sands deposited as the shoreline built out into the basin and the seaway retreated. The Smoky Hollow Member preserves fluvial and lagoonal deposits.

Increased interest in mycorrhizal symbiosis and the development of sophisticated molecular techniques has led to the rapid development of genetic evidence. Wang et al. (2010) investigated plant genes involved in communication with order Glomales fungal partners (DMI1, DMI3, IPD3). These three genes could be sequenced from all major clades of modern land plants, including liverworts, the most basal group, and phylogeny of the three genes proved to agree with then current land plant phylogenies.

Initial sequencing (Karafet et al., 2008) of the human Y chromosome suggested that two most basal Y-chromosome lineages were Haplogroup A and Haplogroup BT. Haplogroup A is found at low frequencies in parts of Africa, but is common among certain hunter-gatherer groups. Haplogroup BT lineages represent the majority of African Y-chromosome lineages and virtually all non-African lineages. Y-chromosomal Adam was represented as the root of these two lineages.

Bahiaxenos relictus is the sole member of the family Bahiaxenidae, a type of winged insect. It was only discovered and described in 2009 from relictual sand dunes associated with the Rio São Francisco in Bahia, Brazil. It is considered to be the most basal living member of the order Strepsiptera, so is the sister taxon to the remaining extant species. It is known from only a single male specimen, and its biology is unknown.

The oldest known globidontan is Acynodon from France, which is also the most basal. Basal globidontans are characterized by their blunt snouts and bulbous teeth. Modern globidontans have flattened snouts and more conical teeth, and are seen as more generalized than earlier globidontans. Generalized forms are usually expected to be ancestral to more specialized forms rather than descendants of them, so it is unusual for basal members of the group to appear specialized.

Relationships between B. oligantha and the other members of B. subg. Isostylis still remain unclear. Though Mast's studies found B. cuneata to be the most basal of the three species, a 2004 study of genetic divergence within the subgenus yielded both other possibilities: some analyses suggested B. ilicifolia as basal, while others suggested B. oligantha. Further complicating the situation is the southernmost (and closest) population of B. cuneata, which has both genetic and phenetic affinities with B. oligantha.

Although the animal is closely related to Morganucodon, it is regarded as the most basal of the mammaliaforms. It differed substantially from the more mammalian Morganucodon in its dental and growth habits. Like other non-mammalian tetrapods, such as reptiles and amphibians, it was polyphyodont, replacing many of its teeth throughout its lifetime, and it seems to have grown slowly but continuously until its death. Sinoconodon is thus less mammalian than early mammaliaforms like docodonts and morganucodonts.

The teeth of Megaconus have many cusps, allowing them to interlock tightly when the jaws are closed. If Megaconus is a non-mammalian mammaliaform, it is one of the most basal mammaliaforms to possess such complex teeth. The middle ear of Megaconus is more primitive than that of modern mammals. The three bones that make up the middle ear in modern mammals — the malleus, incus, and stapes — originated from the lower jaw in the ancestors of mammals.

Recently, Rauhut and Carrano have placed Elaphrosaurinae inside Noasauridae while simultaneously moving the previous noasaurs into Noasaurinae. Into their new Noasauridae, they have uniquely included Deltadromeus and Limusaurus. The oldest known ceratosaur currently described is Berberosaurus liassicus at 185 Ma. Some paleontologists believe that Berberosaurus liassicus, is the most basal ceratosaur currently discovered as well. The placement of B. liassicus has been a topic for debate, with some considering it an abelisaur, while others classifying as a basal polotomy.

Although the evolution of this genus has been studied by a number of authors, details are still being elucidated. A brief summary of the pattern that has emerged is as follows: The most basal split in the genus is between the reptile/bird species and the mammalian species. The bird/reptile clade appears to be related to the genera Haemoproteus, Leukocytozoon and Polychromophilus. The genus Hepatocystis appears to have evolved from with the mammalian species clade.

"A revision of the longipinnate ichthyosaurs of the Lower Jurassic of England, with descriptions of two new species (Reptilia, Ichthyosauria)". Life Sciences Contributions, Royal Ontario Museum 97: 1–37 The family Temnodontosauridae was described by C. McGowan and is from the Lower Liassic. Temnodontosauridae is part of the monophyletic group Neoichthyosauria, a clade named by Martin Sander in 2000 that includes the families Temnodontosauridae, Leptonectidae and Suevoleviathanidae. Temnodontosaurus is one of the most basal post-Triassic ichthyosaurs.

This clade became the basis for new subseries Sphaerocarpae, which Thiele defined as containing those species with lignotubers, styles loosely curling around the infructescence (although this trait was reversed in micrantha), and "transversely aligned cells of the seed wing inner face". Other than the most basal B. grossa, these species also have shouldered follicles. Having found B. micrantha to be more closely related than B. sphaerocarpa var. dolichostyla to the other varieties of B. sphaerocarpa, they promoted var.

Abietinae was found to be very nearly monophyletic, and so retained. It further resolved into four subclades, so Thiele and Ladiges split it into four subseries. Banksia scabrella appeared in the third of these, initially called the "telmatiaea clade" for its most basal member. As with George's classification, B. lanata and two subspecies of B. leptophylla emerged as close relatives of B. scabrella, but there was some question over the relationships between all five forms in the clade.

Benson attributed this revised phylogeny to the inclusion of postcranial characteristics, or features of the skeleton other than the skull, in his analysis. When only cranial or skull features were included, Caseasauria remained the most basal synapsid clade. Below is a cladogram modified from Benson's analysis (2012): However, more recent examination of the phylogeny of basal synapsids, incorporating newly described basal caseids and eothyridids, returned Caseasauria to its position as the sister to all other synapsids. Brocklehurst et al.

Currently there is only one species belonging to the genus Grippia, this species is Grippia longirostris. Grippia longirostris was an entirely marine species and is considered to be the most basal example of Ichthyopterygia. G.longirostris measured in at 1-1.5m (3.3-4.9 feet) in length making it the smallest species within the superorder Ichthyopterygia. Other definitive features of G.longirostris include the arrangement of carpals and metacarpals that constitute the forelimbs and the morphology of the skull.

Ichthyopterygia are fully aquatic reptiles that evolved from terrestrial tetrapods, with no transitional lineage being discovered so far. Grippia is one of earliest examples of the superorder Ichthyopterygia and is fully adapted to aquatic life. Grippia are believed to have lived from 250-235 Ma during the Olenekian – Anisian of the early to mid-Triassic. Grippia are considered to be basal ichthyosaurs along with several other early genus, with Grippia being the most basal of all of them.

In one of the earliest studies of crurotarsan phylogeny, Sereno and Arcucci (1990) found Crurotarsi to be a monophyletic grouping consisting of phytosaurs, ornithosuchids, and the more derived suchians, but produced a trichotomy between the three groups in their tree. In resolving this trichotomy, Parrish (1993) placed ornithosuchids, not phytosaurs, as the most basal crurotarsans. However, most other studies, such as Sereno (1991) and Benton et al. (2010), recover phytosaurs in a basalmost position among crurotarsans.

The skull of a bowfin (Amia calva), one of the most basal living actinopterygiians. Skull bones are labelled based on tetrapod homologies. Watson & Day (1916)'s "orthodox" interpretation of fish skulls argued that fish lacked independent postparietals, with the elongated paired midline bones at the back of the skull being interpreted as parietals. On the other hand, Westoll (1938) proposed an alternative interpretation which identified the bones as postparietals based on comparisons between early tetrapods and their sarcopterygian ancestors.

Eucoelophysis (meaning "true hollow form") is a genus of dinosauriform from the Late Triassic (Norian) period Chinle Formation of New Mexico. It was assumed to be a coelophysid upon description, but a study by Nesbitt et al. found that it was actually a close relative of Silesaurus, which was independently supported by Ezcurra (2006), who found it to be the sister group to Dinosauria, and Silesaurus as the next most basal taxon. However, the relationships of Silesaurus are uncertain.

However, these are not seen after the end of the Early Cretaceous and by the Late Cretaceous marsupials and placentals had evolved from a common eupantotherian ancestor. The Mammalia class probably saw its first eutherian in the early Cretaceous Jehol biota in China called Acristatherium yanesis. This eutherian was determined to be the most basal based on a phylogenetic analysis that used a data matrix of many other species. Metatherians probably evolved to take advantage of open arboreal niches.

Chinshakiangosaurus (JIN-shah-jiahng-uh-SOR-us, meaning "Chinshakiang lizard") is a genus of dinosaur and probably one of the most basal sauropods known. The only species, Chinshakiangosaurus chunghoensis, is known from a fragmentary skeleton found in Lower Jurassic rocks in China. Chinshakiangosaurus is one of the few basal sauropods with preserved skull bones and therefore important for the understanding of the early evolution of this group. It shows that early sauropods may have possessed fleshy cheeks.

The lateral (side) and paramedian (upper) osteoderms each bear prominent spines. Other aetosaurs such as Longosuchus also have neck spines, but only on the lateral osteoderms. The cervical osteoderms are wider than they are long, a feature that unites Gorgetosuchus with the most basal ("primitive") aetosaurs. However, several features of the osteoderms (such as a flange on the lateral cervical osteoderms that overlaps the paramedian osteoderms) link it with the desmatosuchines, a more derived group of aetosaurs.

Reconstruction of Ciurcopterus, the most basal known pterygotid. The clade Pterygotidae is among the best supported within the Eurypterida. Relationships within it has historically been difficult to resolve due to wrong interpretations of genital appendage of Jaekelopterus, and the consequential disturbance of character states historically interpreted as primitive and derived within the group when the error was solved. Subsequent descriptions and redescriptions have ensured that the phylogeny of the clade is rather robust at the genus level.

Reconstruction of Brachyopterus, the earliest known rhenopterid. The Rhenopterids first appeared during the Middle Ordovician as one of the earliest and most basal groups of Stylonurine eurypterids. Clear evolutionary trends can be observed in the carapaces of the rhenopterids. Basal rhenopterids possess broad carapaces narrowest at their base (as in Brachyopterus and Brachyopterella) whilst more derived rhenopterids have broad carapaces narrowest at the front and the most derived members possess narrower carapaces narrowest at the front (as in Rhenopterus).

Phylogenetic analyses based on morphological and molecular data indicate the spadenose shark is one of the most basal members of its family, along with the related genus Rhizoprionodon and Galeocerdo, the tiger shark. In addition, anatomical similarities suggest this species to be the closest living relative of the hammerhead sharks, which diverged from the other carcharhinids some time before the Middle Eocene (48.6-37.2 million years ago).Martin, R.A. Hammerhead Taxonomy. ReefQuest Centre for Shark Research.

Thrinaxodon from the Early Triassic of South Africa Together with the extinct gorgonopsians and the therocephalians, the cynodonts themselves are part of a group of therapsids called theriodonts. The oldest and the most basal cynodont yet found is Charassognathus (Late Permian). Other basal cynodonts were the procynosuchids, a family that includes Procynosuchus and Dvinia. Cynodonts were among the few groups of synapsids that survived the Permian–Triassic extinction event and had a slow recovery after the extinction.

Mouse lemurs, the smallest primates in the world, evolved in isolation along with other lemurs on the island of Madagascar. Lemurs, primates belonging to the suborder Strepsirrhini which branched off from other primates less than 63 million years ago, evolved on the island of Madagascar, for at least 40 million years. They share some traits with the most basal primates, and thus are often confused as being ancestral to modern monkeys, apes, and humans. Instead, they merely resemble ancestral primates.

Y chromosome sequence variation and the history of human populations, Nat. Genet., 26 (2000), pp. 358–361 bearers of extant sub-clades of haplogroup A are entirely found in Africa (or among descendants of recently moved African populations), in contrast with the descendant haplogroup BT (clade II-X) bearers of which participated in the Out of Africa migration of anatomically modern humans. The most basal subclades of haplogroup A are, by age of divergence, "A00", "A0", "A1" (also "A1a-T") and "A2-T".

Acanthoctesia or "archaic sun moths" is an infraorder of insects in the lepidopteran order, containing a single superfamily, Acanthopteroctetoidea, and a single family, Acanthopteroctetidae. They are currently considered the fifth group up on the comb of branching events in the extant lepidopteran phylogeny (Kristensen and Skalski, 1999: 10). They also represent the most basal lineage in the lepidopteran group Coelolepida (Wiegmann et al., 2002) (along with Lophocoronoidea and the massive group "Myoglossata") characterised in part by its scale morphology (Kristensen, 1999: 53-54).

Relationships between B. cuneata and the other members of B. subg. Isostylis still remain unclear. Though Mast's studies found B. cuneata to be the most basal of the three species, a 2004 study of genetic divergence within the subgenus yielded both other possibilities: some analyses suggested B. ilicifolia as basal, while others suggested B. oligantha. Further complicating the situation is the southernmost population of B. cuneata, which has both genetic and phenetic affinities with B. oligantha located to the southeast.

In his massive revision of archosaurs which included a large cladistic analysis, Sterling J. Nesbitt (2011) found Xilousuchus to be a poposauroid most closely related to Arizonasaurus. Nesbitt's analysis did not recover a monophyletic Rauisuchia or monophyletic Rauisuchoidea. Poposauroidea was found to be monophyletic, and more resolved than in previous analyses, with Qianosuchus as the most basal member of the group and Lotosaurus grouping with shuvosaurids instead of ctenosauriscids. The cladogram below follows Nesbitt (2011) with clade names based on previous studies.

Molecular analyses have been similarly equivocal regarding the blacknose shark's phylogenetic relationships: Gavin Naylor's 1992 allozyme analysis found this species to be the most basal member of Carcharhinus, while Mine Dosay-Abkulut's 2008 ribosomal DNA analysis indicated affinity between it and the blacktip shark (C. limbatus) or the smalltail shark (C. porosus). The whitenose shark (Nasolamia velox), found along the tropical western coast of the Americas, may be descended from blacknose sharks that experienced the teratogenic effects of incipient cyclopia.

For many decades, the precise taxonomic classification of the giant panda was under debate because it shares characteristics with both bears and raccoons. However, molecular studies indicate the giant panda is a true bear, part of the family Ursidae. These studies show it diverged about from the common ancestor of the Ursidae; it is the most basal member of this family and equidistant from all other extant bear species. The giant panda has been referred to as a living fossil.

Linhenykus is an extinct genus of alvarezsaurid theropod dinosaur from the Late Cretaceous of Inner Mongolia, China. It is the most basal known member of the Parvicursorinae. The genus gets its name from Linhe, a city near the site where the fossil was first found and Greek nykus, "claw". The specific name is derived from Greek monos, "single", and daktylos, "finger", a reference to the fact that it is the only known non-avian dinosaur to have had but a single digit.

Some studies have considered the most basal major clade of archosauromorphs, close to the split between Archosauromorpha and its sister group Lepidosauromorpha, whose modern representatives are lizards and snakes. The monophyly of Protorosauria is debatable, with many studies considering it a grade of early archosauromorphs rather than a natural clade. However, when Ezcurra et al. (2014) included Eorasaurus olsoni for the first time in a phylogenetic analysis, they found it to be a member of Archosauriformes, a more derived clade within Archosauromorpha.

The results of the cladistic analysis of Gunnell et al. (2018) recovered Propotto as the most basal member of Chiromyiformes, supporting the hypothesis that lemurs migrated to Madagascar in two distinct waves from Africa, perhaps in the late Cenozoic.Gregg F. Gunnell; Doug M. Boyer; Anthony R. Friscia; Steven Heritage; Fredrick Kyalo Manthi; Ellen R. Miller; Hesham M. Sallam; Nancy B. Simmons; Nancy J. Stevens; Erik R. Seiffert (2018). "Fossil lemurs from Egypt and Kenya suggest an African origin for Madagascar's aye-aye".

The study indicated that throughout history, global dog populations experienced numerous episodes of diversification and homogenization, with each round further reducing the power of genetic data derived from modern breeds to help infer their early history. Of the basal breeds, the American Eskimo Dog and Eurasier were the very recent product of cross-breeding other basal breeds. Most basal breeds have hybridized with other lineages in the past. If those other lineages were other basal breeds then a basal genetic signature remains.

The skulls of ornithomimosaurs were small, with large eyes, above relatively long and slender necks. The most basal members of the taxon (such as Pelecanimimus and Harpymimus) had a jaw with small teeth, while the later and more derived species had a toothless beak.Last of the Dinosaurs: The Cretaceous Period The fore limbs ("arms") were long and slender and bore powerful claws. The hind limbs were long and powerful, with a long foot and short, strong toes terminating in hooflike claws.

Several recent discoveries of possible ceratosaurs have begun reshaping the phylogeny of Ceratosauria by filling in some of these gaps. Specifically, this has allowed paleontologists to begin altering the sub-groups inside Ceratosauria, in an attempt to find their most basal members. Currently, most paleontologists agree that Ceratosauria divides into two sub groups, Ceratosauridae and Abelisauroidea, with some variance as to which taxa are placed into basal polotomy. Abelisauroidea is further divided into the Abelisauridae and Noasauridae, with Abelisauridae, including Carnotaurinae.

A phylogenetic analysis conducted by Nesbitt (2011), one of the most extensive on archosaurs, found CM 73372 to be the most basal crocodylomorph, thus referable neither to P. kirkpatricki nor to Rauisuchidae. In their description of Vivaron, Lessner et al. (2016) questioned the random referral of all rauisuchid material from the southwestern US to Postosuchus, saying that the discovery of Vivaron stresses the need for a re-appraisal of all material from localities younger or older than unequivocal remains of Postosuchus and Vivaron.

Coral snakes (discovered in 1867) are a large group of elapid snakes that can be subdivided into two distinct groups, Old World coral snakes and New World coral snakes. There are 16 species of Old World coral snake in three genera (Calliophis, Hemibungarus, and Sinomicrurus), and over 65 recognized species of New World coral snakes in three genera (Leptomicrurus, Micruroides, and Micrurus). Genetic studies have found that the most basal lineages are Asian, indicating that the group originated in the Old World.

Kjellesvig-Waering (1966) concluded that "there is no other genus that warrants comparison, or, indeed at our present state of knowledge, reveals any close affinities with this very unusual genus", though the genus was able to be classified as a stylonurine. In later years, further similarities have been noted between Brachyopterus and the rhenopterids. Lamsdell et al. (2010) classified it as the most basal of the rhenopterids and a sister taxon to more derived rhenopterids (such as Kiaeropterus and Rhenopterus).

Benson attributed this revised phylogeny to the inclusion of postcranial characteristics, or features of the skeleton other than the skull, in his analysis. When only cranial or skull features were included, Caseasauria remained the most basal synapsid clade. Below is a cladogram modified from the analysis of Benson (2012): However, more recent examination of the phylogeny of basal synapsids, incorporating newly described basal caseids and eothyridids, returned Caseasauria to its position as the sister to all other synapsids. Brocklehurst et al.

Eosuchus (Dawn Crocodile) is an extinct genus of eusuchian crocodylomorph, usually regarded as a gavialoid crocodilian. It might have been among the most basal of all gavialoids, lying crownward of all other known members of the superfamily, including earlier putative members such as Thoracosaurus and Eothoracosaurus. Fossils have been found from France as well as eastern North America in Maryland, Virginia, and New Jersey. The strata from which specimens have been found date back to the late Paleocene and early Eocene epochs.

Artist's life restoration Skeletal reconstruction The authors of the original description considered Jinfengopteryx to be the most basal avialan (bird), and a member of the family Archaeopterygidae. In a 2007 follow-up paper, they went on to compare Jinfengopteryx and Archaeopteryx, still supporting its placement as an archaeopterygid, but providing no phylogenetic analysis.Ji S., and Ji, Q. (2007). "Jinfengopteryx compared to Archaeopteryx, with comments on the mosaic evolution of long-tailed avialan birds." Acta Geologica Sinica (English Edition), 81(3): 337-343.

Series B: Biological Sciences, 263(1376), 1589–1598. Cichlidae can be split into a few groups based on their geographic location: Madagascar, Indian, African, and Neotropical (or South American). The most famous and diverse group, the African cichlids, can be further split either into Eastern and Western varieties, or into groups depending on which lake the species is from: Lake Malawi, Lake Victoria, or Lake Tanganyika. Of these subgroups, the Madagascar and Indian cichlids are the most basal and least diverse.

The position of Compsognathus and its relatives within the coelurosaur group is uncertain. Some, such as theropod expert Thomas Holtz Jr. and co-authors Ralph Molnar and Phil Currie in the landmark 2004 text Dinosauria, hold the family as the most basal of the coelurosaurs, while others as part of the Maniraptora. For almost a century, Compsognathus longipes was the only well-known small theropod species. This led to comparisons with Archaeopteryx and to suggestions of an especially close relationship with birds.

The generic name means "mountain", oro, in Greek in reference to the Richards Spur locality, which was mountainous during the Permian period and "hunter", venator, in Latin. The specific name honours Bill and Julie May. Orovenator is the oldest and most basal neodiapsid to date. A 2018 redescription by David Ford and Roger Benson found that Orovenator shared many similarities with varanopids, a group of reptile-like tetrapods traditionally considered to be synapsids (amniotes more closely related to mammals than to modern reptiles).

However, Vasconcelos and Yates (2004) found Gryponyx to be distinctive enough from other basal sauropodomorphs to be placed in its own genus. They found that it differs from other taxa by the following characteristics: total length of metacarpal I exceeds maximum proximal width and a long, narrow pubic apron with straight lateral margins. Although this publication wasn't formal, they conducted a cladistic analysis using Yates (2004) sauropodomorph matrix and found Gryponyx to be the most basal massospondylid.C. C. Vasconcelos, A. M. Yates (2004).

An unnamed specimen from Brazil indicates that this group persisted at least until the end of the Early Cretaceous. Most analyses find Dicraeosaurus and Brachytrachelopan to be more closely related to each other than to Amargasaurus. Suuwassea is generally recovered as the most basal member of the family. A 2015 analysis by Tschopp and colleagues came to the preliminary result that two poorly known genera from the Morrison Formation, Dyslocosaurus polyonychius and Dystrophaeus viaemalae, might be additional members of the Dicraeosauridae.

The generic name combines the Greek prefix eos/ἠώς ("dawn", "morning", implying "early") with the suffix lambia (derived from Lambeosaurus, which is in turn named after Canadian paleontologist Lawrence Lambe). In all, the genus name means "dawn (or early) lambeosaurine", in reference to its supposed position as the most basal lambeosaurine. Meanwhile, the specific name honors Carole Jones. The name Eolambia was suggested by paleoartist Michael Skrepnick; it replaced the informal name "Eohadrosaurus caroljonesi", which was used by Kirkland before the 1998 paper.

Claytonia umbellata is a species of wildflower in the purslane family known by the common name Great Basin springbeauty. It is native to the Great Basin of the United States, where it grows mainly in subalpine coniferous forests, often on north-facing exposed slopes in the talus. It is a perennial herb growing from a tuberous root up to 5 centimeters wide and a thin taproot. Most of the stem develops underground, as do the petioles of the most basal leaves.

Yates and Warren (2000) erected Limnarchia in their phylogenetic study of stereospondyls and their relatives. They found support for two major divisions of temnospondyls, which they named Euskelia and Limnarchia. Limnarchia included a group of small-bodied aquatic temnospondyls called Dvinosauria as the most basal members of the clade, followed by the large-bodied Archegosauroidea and the diverse Stereospondyli, which together formed the clade Stereospondylomorpha. Below is a cladogram from Yates and Warren (2000) showing this phylogeny:Sigurdsen, T.; Bolt, J.R. (2010).

Pterodactyloids were the last surviving pterosaurs when the order became extinct at the end of the Cretaceous Period, together with the non-avian dinosaurs and most marine reptiles. "Pterodactyl" is also a common term for pterodactyloid pterosaurs, though it can also be used to refer to Pterodactylus specifically or (incorrectly) to pterosaurs in general. Well-known examples of pterodactyloids include Pterodactylus, Pteranodon, and Quetzalcoatlus. In 2014, fossils from the Shishugou Formation of China were classified as the most basal pterodactyloid yet found, Kryptodrakon.

The holotype, IVPP V11525, is known from a nearly complete skeleton exposed in a dorsal view on a shale slab. Its total body length (from snout to vent) is estimated at approximately 94 mm. It differs morphologically in many respects from all other discoglossoids, including the number of presacral vertebrae (9 instead of the usual 8) and other primitive characters. Although it had a mosaic of primitive and derived characters, it can be unequivocally placed as the most basal taxon of the clade.

Of these two species, Candidatus Giganthauma insulaporcus and Candidatus Giganthauma karukerense, the latter is associated with Gammaproteobacteria with which it may have a symbiotic relationship, though the nature of this relationship is unknown. The two species are very large, forming filaments larger than ever before observed in archaea. As with many Thaumarchaea, they are mesophilic. Genetic analysis and the observation that the most basal identified Thaumarchaeal genomes are from hot environments suggests that the ancestor of Thaumarchaeota was thermophilic, and mesophily evolved later.

Expansion into Africa appears to have occurred later, as most derived forms are found there. An alternative scenario would be African origin for the entire "sturnoid" group, with the oxpeckers representing an ancient relict and the mimids arriving in South America. This is contradicted by the North American distribution of the most basal Mimidae. As the fossil record is limited to quite Recent forms, the proposed Early Miocene (about 25–20 mya) divergence dates for the "sturnoids" lineages must be considered extremely tentative.

Having less than the maximum and ideal level of genetic diversity means poor adaptive capacity to respond to changing environmental pressures under the hypothesis, and higher than the ideal maximum means damage to the basic physiology of the organism because its most basal instructions become damaged. The hypothesis proposes that a population will have the most evolutionary success when its diversity level is properly tuned to its environment, and when the levels of its slow- and fast-mutating alleles are optimally balanced.

The Indo-Pacific finless porpoise ('), or finless porpoise, is one of seven porpoise species. Most of the population has been found around the Korean peninsula in the Yellow and East China Seas, although a freshwater population is found around Jiuduansha near Shanghai at the mouth of China's Yangtze River. Genetic studies indicate that the finless porpoise is the most basal living member of the porpoise family. There is a degree of taxonomic uncertainty surrounding the species, with the N. p.

The species was described and named by Rupert Wild in 1984. The genus name refers to Preone, the specific name honours Buffarini. Rupert classified the new species within Rhamphorhynchidae, of which group very old species are known such as Dorygnathus, but soon it was understood the form was much more basal. A cladistic analysis by David Unwin found Preondactylus as the most basal pterosaur, and the species was accordingly used by him for a node clade definition of the clade Pterosauria.

The next report of clavicles in a dinosaur was in a Russian article in 1983.In an Oviraptor: See the summary and pictures at Contrary to what Heilmann believed, paleontologists now accept that clavicles and in most cases furculae are a standard feature not just of theropods but of saurischian dinosaurs. Up to late 2007 ossified furculae (i.e. made of bone rather than cartilage) have been found in all types of theropods except the most basal ones, Eoraptor and Herrerasaurus.

The probainognathians are members of one of the two major clades of the infraorder Eucynodontia, the other being Cynognathians. The earliest forms were carnivorous and insectivorous, though some species eventually also evolved herbivorous diets. The earliest and most basal probainognathian is Lumkuia, from South Africa. Three groups survived the extinction at the end of Triassic: the Tritheledontidae and Tritylodontidae, who both survived until the Jurassic—the latter possibly even into the Cretaceous (Xenocretosuchus)—and Mammaliaformes, who gave rise to the mammals.

Australothyris is an extinct genus of basal procolophonomorph parareptile known from the Middle Permian (middle Capitanian stage) of Tapinocephalus Assemblage Zone, South Africa. The type and only known species is Australothyris smithi. As the most basal member of Procolophonomorpha, Australothyris helped to contextualize the origin of this major parareptile subgroup. It has been used to support the hypotheses that procolophonomorphs originated in Gondwana and ancestrally possess temporal fenestrae, due to its large and fully enclosed temporal fenestra and South African heritage.

Afroaves is a clade of birds, consisting of the kingfishers and kin (Coraciiformes), woodpeckers and kin (Piciformes), hornbills and kin (Bucerotiformes), trogons (Trogoniformes), cuckoo roller (Leptosomiformes), mousebirds (Coliiformes), owls (Strigiformes), raptors (Accipitriformes) and New World vultures (Cathartiformes). The most basal clades are predatory, suggesting the last common ancestor of Afroaves was also a predatory bird. The following Cladogram of Afroaves relationships is based on Jarvis et al (2014), with some clade names after Yury, T. et al. (2013) and Kimball et al. (2013).

The Pelagornithidae, commonly called pelagornithids, pseudodontorns, bony- toothed birds, false-toothed birds or pseudotooth birds, are a prehistoric family of large seabirds. Their fossil remains have been found all over the world in rocks dating between the Early Paleocene and the Pliocene-Pleistocene boundary.Bourdon (2005), Mayr, G. (2008), Boessenecker and Smith (2011)Gerald Mayr, G. et al. (2019) Oldest, smallest and phylogenetically most basal pelagornithid, from the early Paleocene of New Zealand, sheds light on the evolutionary history of the largest flying birds.

A hammerhead shark gliding along the sea bed Since sharks do not have mineralized bones and rarely fossilize, their teeth alone are commonly found as fossils. The hammerheads seem closely related to the carcharhinid sharks that evolved during the mid-Tertiary period. According to DNA studies, the ancestor of the hammerheads probably lived in the Miocene epoch about 20 million years ago. Using mitochondrial DNA, a phylogenetic tree of the hammerhead sharks showed the winghead shark as its most basal member.

Long, 2001. He also noted that the presence of a rotational tooth whorl combined with the other characteristics in the skull, and possibly in the shoulder girdle, show that Psarolepis is better placed as a sister taxon to Onychodus as the most basal member of the group of Onychodontiforms. Moreover, Long, referring to new fossils collected from Gogo Formation, Western Australia, said that Psarolepis and Onychodus are both basal bony fish and are more primitive than other lobe- finned groups.

The timing and number of hypothesized colonizations has traditionally hinged on the phylogenetic affinities of the aye-aye, the most basal member of the lemur clade. Having undergone their own independent evolution on Madagascar, lemurs have diversified to fill many niches normally filled by other types of mammals. They include the smallest primates in the world, and once included some of the largest. Since the arrival of humans approximately 2,000 years ago, lemurs are now restricted to 10% of the island, or approximately , with many facing extinction.

Neoophora is a group of rhabditophoran flatworms with ectolecithal eggs, i.e., yolk is not present in the egg as in most animals, but rather is secreted by accessory glands called vitellaria or yolk glands. These glands have the same embryonic origin as the ovaries, but usually constitute a separate organ in adult animals. The monophyly of Neoophora is disputed, since some recent molecular studies indicated that the most basal order, Lecithoepitheliata, is more closely related to Polycladida, a non-neoophoran order, than to other neoophorans.

By this definition, haplogroup A includes all mutations that took place between the Y-MRCA (estimated at some 270 kya) and the mutation defining haplogroup BT (estimated at some 80-70 kya), including any extant subclades that may yet to be discovered. Bearers of haplogroup A (i.e. absence of the defining mutation of haplogroup BT) have been found in Southern Africa's hunter-gatherer inhabited areas, especially among the San people. In addition, the most basal mitochondrial DNA L0 lineages are also largely restricted to the San.

However, the A lineages of Southern Africa are sub-clades of A lineages found in other parts of Africa, suggesting that A sub-haplogroups arrived in Southern Africa from elsewhere. as PDF The two most basal lineages of haplogroup A, A0 and A1 (prior to the announcement of the discovery of haplogroup A00 in 2013), have been detected in West Africa, Northwest Africa and Central Africa. Cruciani et al. (2011) suggest that these lineages may have emerged somewhere in between Central and Northwest Africa.

Enkianthus is a genus of shrubs or small trees in the heath family (Ericaceae). Its native range is in Asia, as far west as the eastern Himalayas, as far south as Indochina, and as far north and east as China and Japan. This genus is considered cladistically the most basal member of the Ericaceae, that is, the descendant of the common ancestor of that Ericaceae that branched earliest from the rest of that family. It is classified as the sole member of the subfamily Enkianthoideae.

Hebree's 2007 review of North American amphisbaenians also included a phylogenetic analysis of rhineurids and other amphisbaenian lizards. The analysis found that Rhineura floridana is the most basal species within the family, meaning its lineage was the first to diverge from the group. However, the species itself is quite young, with the oldest fossils coming from the Pleistocene of Florida. The ancestor of R. floridana likely migrated into what is now Florida from the continental interior, while the remaining rhineurids remained there to radiate and diversify.

They noted that if their tree was enlarged by one step, Poposauroidea fell outside Rauisuchia to become the sister group of Ornithosuchidae, which is thought to closely related to, but outside, Rauisuchia. In their tree, Poposauroidea included genera usually classified as poposauroids as well as several other genera that were not previously placed in the group. One of these genera, Qianosuchus, is unique among pseudosuchians in its semiaquatic lifestyle. Qianosuchus mixtus, an unusual semiaquatic archosaur that was placed as the most basal poposauroid in Nesbitt's phylogenetic analysis.

The Karbi language (), is spoken by the Karbi (also known as Mikir or Arleng) people of Northeastern India. It belongs to the Sino-Tibetan language family, but its position is unclear. Grierson (1903)Linguistic survey of India vol III Part II classified it under Naga languages, Shafer (1974) and Bradley (1997) classify the Mikir languages as an aberrant Kuki-Chin branch, but Thurgood (2003) leaves them unclassified within Sino-Tibetan. Blench and Post (2013) classify it as one of the most basal languages of the entire family.

Diabolepis (or Diabolichthys) is an extinct genus of very primitive lungfish which lived about 400 million years ago, in the Early Devonian period of South China. Diabolepis is the most basal known dipnoan. A rather small fish, the fossil has risen to prominence as it has four nares like most fish, while modern lungfish have only two, the hindmost pair having moved on to the palate serving as choanae. This proved that the internal nares of lungfish had evolved independently of those in tetrapods.

Life restoration of Edops craigi, the most basal edopoid Edopoidea was named as a superfamily of temnospondyls by American paleontologist Alfred Romer in the second edition of his textbook Vertebrate Paleontology, published in 1945. He recognized a close relationship between the families Edopidae (which includes only Edops) and Cochleosauridae. In the late 1980s and early 1990s, the relationship between these two groups was supported by many phylogenetic analyses. One phylogenetic analysis separated Edops and cochleosaurids, finding the cochleosaurids to group with more derived temnospondyls like Archegosaurus.

The petrous part of the temporal bone is pyramid-shaped and is wedged in at the base of the skull between the sphenoid and occipital bones. Directed medially, forward, and a little upward, it presents a base, an apex, three surfaces, and three angles, and houses in its interior, the components of the inner ear. The petrous portion is among the most basal elements of the skull and forms part of the endocranium. Petrous comes from the Latin word petrosus, meaning "stone-like, hard".

It has been considered a highly derived member of the family Indridae, a basal branch of the strepsirrhine suborder, and of indeterminate relation to all living primates. In 1931, Anthony and Coupin classified the aye-aye under infraorder Chiromyiformes, a sister group to the other strepsirrhines. Colin Groves upheld this classification in 2005 because he was not entirely convinced the aye-aye formed a clade with the rest of the Malagasy lemurs. However, molecular results have consistently placed Daubentonia as the most basal of lemurs.

This suggests that the necks of brachiosaurids became proportionally much longer while their backs, to the contrary, experienced relative negative growth. The humerus of SMA 0009 is relatively robust: it is more slender than that of most basal titanosauriforms but thicker than the upper arm bone of B. altithorax. This suggests that it was already lengthening in an early juvenile stage and became even more slender during growth. This is in contrast to diplodocoids and basal macronarians, whose slender humeri are not due to such allometric growth.

They suggested that mesonychids gave rise to pakicetids, which gave rise to ambulocetids, which gave rise to both protocetids and remingtonocetids. Though middle-to-late- Eocene archaeocetes are also known from North America, Europe, and Africa, the most basal of these are found only on the Indian subcontinent. Therefore, it is thought cetaceans originally evolved in that region. Based on molecular data, cetaceans are most closely allied with hippos (Whippomorpha) and to the hoofed even-toed ungulates (Cetartiodactyla), and they split approximately 55 million years ago.

The amount of vertical compression in plagiosaurids varies somewhat with the most basal member, Plagiosuchus, being only somewhat compressed while more derived members such as Gerrothorax and Megalopthalma being much significantly more compressed. Their skull, also vertically compressed, has dorsally oriented large orbital fenestrae and contained a battery of small teeth the curve inward. The trunks of these animals have shortened limbs relative their body size and the backs were generally covered in bony armor which is denser in the more derived members of the clade.

Archicebus achilles exhibits similarities with simians with regard to the shape of its calcaneus and the proportions of its metatarsals, yet its skull, teeth, and appendicular skeleton resemble those of tarsiers. According to phylogenetic analysis, all of these traits taken together suggest it is the most basal member of the tarsiiform clade within the suborder Haplorhini. Considering its age, and since simians are a sister group to tarsiiforms, A. achilles may closely resemble the common ancestor of haplorhines and possibly the last common ancestor of all primates.

This is the most basal living member of its subfamily, and it lacks the stiff tail and swollen bill of its relatives. Overall much resembling a fairly typical diving duck, its plumage and other peculiarities indicate it is not a very close relative of these, but rather the product of convergent evolution in the ancestors of the stiff-tailed ducks. It is a small, dark duck, the male with a black head and mantle and a paler flank and belly, and the female pale brown overall.

Haplorhini (the haplorhines or the "dry-nosed" primates; the Greek name means "simple-nosed") is a suborder of primates containing the tarsiers and the simians (Simiiformes or anthropoids), as sister of the Strepsirrhini ("moist- nosed"). The name is sometimes spelled Haplorrhini. The simians include catarrhines (Old World monkeys and apes including humans), and the platyrrhines (New World monkeys). The extinct omomyids, which are considered to be the most basal haplorhines, are believed to be more closely related to the tarsiers than to other haplorhines.

Mahakala (from Sanskrit, named for Mahakala, one of eight protector deities (dharmapalas) in Tibetan Buddhism) is a genus of halszkaraptorine theropod dinosaur from the Campanian-age (about 80 million years ago) Upper Cretaceous Djadokhta Formation of Ömnögovi, Mongolia. It is based on a partial skeleton found in the Gobi Desert. Mahakala was a small dromaeosaurid (approximately 70 centimeters long (28 in)), and its skeleton shows features that are also found in early troodontids and avialans. Despite its late appearance, it is among the most basal dromaeosaurids.

W.P. Coombs. 1978. "Forelimb muscles of the Ankylosauria (Reptilia, Ornithischia)". Journal of Paleontology 52(3): 642-657 Cladistic analysis of Struthiosaurus indicates that the taxon is a basal member of the Nodosauridae and suggested it may be one of the most basal ankylosaurs in the clade Ankylosauria. An analysis by Ösi in 2005, describing the taxon Hungarosaurus, found that while being younger in age than other nodosaurids, Struthiosaurus was one of the more basal taxa, although many features could not be coded for it.

DNA analysis shows that the first three form monophyletic clades. The wolf-like canines and the South American canines together form the tribe Canini. Molecular data imply a North American origin of living Canidae some 10 Mya and an African origin of wolf-like canines (Canis, Cuon, and Lycaon), with the jackals being the most basal of this group. The South American clade is rooted by the maned wolf and bush dog, and the fox-like canines by the fennec fox and Blanford's fox.

Prior to their description, the specimens that would later be assigned to Umoonasaurus were thought to represent a new species of Leptocleidus. In 2006, Kear and colleagues found Umoonasaurus to belong to the superfamily Pliosauroidea and be the most basal member of the family Rhomaleosauridae. They found the latter surprising, as Umoonasaurus was also identified as the last surviving member of that family. Leptocleidus was recovered as a more derived rhomaleosaurid, although it was still considered plausible that the two might be close relatives.

Germanodactylus is the first genus for which a soft-tissue component of the crest is known, but similar structures were probably widespread among pterosaurs. Head crests like these are now known to be far more extensive in Pterosauria. Of all the pterosaurs known to date, the most basal form with such a crest is Austriadactylus and the most derived are Hamipterus and Tapejara. Darwinopterus and Cuspicephalus also possess headcrests made of "fibrous" bone, demonstrating that the character is a homology, and not a homoplasy.

Modern marsupials appear to have reached the islands of New Guinea and Sulawesi relatively recently via Australia. A 2010 analysis of retroposon insertion sites in the nuclear DNA of a variety of marsupials has confirmed all living marsupials have South American ancestors. The branching sequence of marsupial orders indicated by the study puts Didelphimorphia in the most basal position, followed by Paucituberculata, then Microbiotheria, and ending with the radiation of Australian marsupials. This indicates that Australidelphia arose in South America, and reached Australia after Microbiotheria split off.

Members of this genus could grow up to 20 feet (6.2 meters) long, although they were significantly lighter than similarly-sized carnivorous contemporaries such as Ceratosaurus. Rauhut & Carrano (2016) listed several features which could be used to diagnose Elaphrosaurinae. Elaphrosaurine cervical vertebrae are amphicoelous, meaning that both their front and rear faces are concave, particularly the front face which is quite strongly concave. While strongly concave front faces are common among many archosaurs, they are quite rare in all but the most basal theropods.

Though Mast's studies found B. cuneata to be the most basal of the three species, a 2004 study of genetic divergence within the subgenus yielded both other possibilities: some analyses suggested B. ilicifolia as basal, while others suggested B. oligantha. Further complicating the situation is the existence of a population of B. cuneata having both genetic and phenetic affinities with B. oligantha. The origin of this population is unknown. It might have arisen through hybridisation, or it may be a transitional or even ancestral form.

In 1796, Pierre André Latreille erected the family "Phalangida" for the then known harvestmen, but included the genus Galeodes (Solifugae). Tord Tamerlan Teodor Thorell (1892) recognized the suborders Palpatores, Laniatores, Cyphophthalmi (called Anepignathi), but also included the Ricinulei as a harvestman suborder. The latter were removed from the Opiliones by Hansen and William Sørensen (1904), rendering the harvestmen monophyletic. According to more recent theories, Cyphophthalmi, the most basal suborder, are a sister group to all other harvestmen, which are according to this system called Phalangida.

Given that the most basal extant members of both Afroaves (Accipitrimorphae, Strigiformes) and Australaves (Cariamiformes, Falconiformes) are carnivorous, it has been suggested that the last common ancestor of all Telluraves was probably a predator. Other researchers are skeptical of this assessment, citing the herbivorous cariamiform Strigogyps as evidence to the contrary.Mayr, G. & Ritchter, G. (2011) Exceptionally preserved plant parenchyma in the digestive tract indicates a herbivorous diet in the Middle Eocene bird Strigogyps sapea (Ameghinornithidae). Paläontologische Zeitschrift, Volume 85, Issue 3, pp 303–307.

Life restoration Restoration of head with speculative parrot-like tongue Incisivosaurus, as well as its potential synonym Protarchaeopteryx, were included in the phylogenetic analysis of a 2014 study on the group Paraves and its relatives. In the unweight cladogram, Incisivosaurus was rendered as the sister taxon to Protarchaeopteryx, with their group being the most primitive oviraptorosaurians. In both weighted analyses however, Protarchaeopteryx was found to be the most primitive oviraptorosaurian, with Incisivosaurus as the next most basal. One of the weighted cladograms, using TNT, is shown below.

However, Prestosuchus, one of the most basal loricatans, had a larger posteromedial tuber. Nevertheless, even more basal loricatans such as Mandasuchus had tubera of equal sizes, indicating that the situation in Prestosuchus was an anomaly. The femoral head may also have possessed a straight groove on its upper side in the earliest paracrocodylomorphs. This final trait is known in poposauroids and a few loricatans more basal than Fasolasuchus, but it is also unknown in Ticinosuchus and present in Nundasuchus so it may have predated Paracrocodylomorpha.

Within Coelurosauria exists a slightly less inclusive clade named Tyrannoraptora. This clade was defined by Sereno (1999) as "Tyrannosaurus rex, Passer domesticus (the house sparrow), their last common ancestor, and all of its descendants". As tyrannosauroids are considered to be the most basal large group within Coelurosauria, this means that the common ancestor of tyrannosauroids and birds was an even more basal coelurosaurian. As a result, almost all coelurosaurians are also tyrannoraptorans, with the only exceptions being particularly basal species such as Zuolong salleei or Sciurumimus albersdoerferi.

Eothoracosaurus is an extinct genus of eusuchian crocodylomorph which existed during the Late Cretaceous and early Paleocene. The animal is usually regarded as a gavialoid crocodilian, though the phylogenetic study published by Lee & Yates (2018) indicated that it was more likely to be a non-crocodilian eusuchian. If the animal was a gavialoid, it was one of the earliest and most basal gavialoids known. Fossils are present from the Ripley Formation in Mississippi and date back to the early Maastrichtian stage of the Late Cretaceous.

The APG IV system, of 2016 (and the earlier 2009 APG III system and 2003 APG II system), recognise Austrobaileyaceae, placing it in the order Austrobaileyales. Austrobaileyales is accepted as being among the most basal lineages in the clade angiosperms. The Cronquist system, of 1981, assigned the family to the order Magnoliales, in subclass Magnoliidae, in class Magnoliopsida [=dicotyledons] of division Magnoliophyta [=angiosperms]. The Thorne system (1992) placed it in the order Magnoliales, which was assigned to superorder Magnolianae, in subclass Magnoliideae [=dicotyledons], in class Magnoliopsida [=angiosperms].

Reconstructed skeleton, Rainbow Forest Museum In 1870, Seeley assigned Dimorphodon to its own family, Dimorphodontidae, with Dimorphodon as the only member. It was suggested in 1991 by the German paleontologist Peter Wellnhofer that Dimorphodon might be descended from the earlier European pterosaur Peteinosaurus. Later exact cladistic analyses are not in agreement. According to Unwin, Dimorphodon was related to, though probably not a descendant of, Peteinosaurus, both forming the clade Dimorphodontidae, the most basal group of the Macronychoptera and within it the sister group of the Caelidracones.

Fossils were found in the Sihetun locality of the western part of Liaoning province, in the lower part of the Yixian Formation, and date to approximately 124.6 Ma. Another specimen was collected near Heitizigou, south of Beipiao. The specimen has a snout–vent length of . Liaobatrachus is considered to be the most basal member of Discoglossidae based on phylogenetic analysis. As frogs are rarely found as articulated skeletons in the fossil record, the discovery of this new taxon has provided important insight into anuran evolution.

Collomia diversifolia is a species of flowering plant in the phlox family known by the common name serpentine collomia. It is endemic to California, where it is an uncommon member of the serpentine soils flora in the North Coast Ranges from the northern San Francisco Bay Area to Shasta County. It is a small annual herb with many branches bearing dark, slightly hairy, lance- shaped leaves, the most basal ones having three small teeth. The inflorescence is a cluster of several flowers each about a centimeter wide.

These deposits are 120 million years old, whereas the original specimen was 125 million years old, meaning the age range for this species is 125-120Ma. Archaeorhychus is one of the earliest avialans known to have had a beak, and represents one of the most basal ornithuromorph avialans. The fossils preserved feathers associated with the neck, head and tail regions. The fossils also show grooves and openings/ holes (foramina) on the tips of the upper and lower jaws, suggesting that it supported a horny bill.

Pulau Ubin island, Singapore. The banded pig (Sus scrofa vittatus) also known as the Indonesian wild boar is a subspecies of wild boar native to the Thai-Malay Peninsula and many Indonesian islands, including Sumatra, Java, and the Lesser Sundas as far east as Komodo. It is known as the wild boar in Singapore. It is the most basal subspecies, having the smallest relative brain size, more primitive dentition, and unspecialised cranial structure.Hemmer, H. (1990), Domestication: The Decline of Environmental Appreciation, Cambridge University Press, pp.

Urocyon (from the Greek word for "tailed dog"Urocyon.) is a genus of Canidae which includes the gray fox (Urocyon cinereoargenteus) and the island fox (Urocyon littoralis). These two fox species are found in the Western Hemisphere. Whole genome sequencing indicates that Urocyon is the most basal genus of the living canids. Fossils of what is believed to be the ancestor of the gray fox, Urocyon progressus, have been found in Kansas and date to the Upper Pliocene, with some undescribed specimens dating even older.

The lower third of the blade is pinnate (cut all the way to the rachis and attached by a narrow costa) to pinnatifid (cut into deep lobes fused across the rachis). There are typically no more than three pairs of pinnae, and sometimes even the most basal part of the leaf is pinnatifid. The upper portion of the leaf is lobed, coming to an acute, straight-sided tip at the end of the leaf. The leaves have a few fine, soft hairs on the upper surface only.

As current estimates on TMRCA converge with estimates for the age of anatomically modern humans and well predate the Out of Africa migration, geographical origin hypotheses continue to be limited to the African continent. According to Cruciani et al. 2011, the most basal lineages have been detected in West, Northwest and Central Africa, suggesting plausibility for the Y-MRCA living in the general region of "Central-Northwest Africa".In a sample of 2204 African Y-chromosomes, 8 chromosomes belonged to either haplogroup A1b or A1a.

In some respects Protohadros was intermediate in morphology to more derived hadrosaurids. Like these it did have pleurokinesis, a cranial joint system that produced the food-grinding action, but only partially in that the quadrate at the back of the skull was still relatively immobile. Protohadros' rear legs were probably longer than the front pair, and it could move on all fours or walk and run on its hind legs only. Protohadros was first described as the most basal member of the Hadrosauridae, hence its generic name.

According to a phylogenetic analysis conducted along with its initial description, Raranimus is considered to be the basalmost therapsid. There has been some controversy as to whether Tetraceratops is a therapsid or a more basal pelycosaur. If Tetraceratops is a therapsid, as has recently been proposed, it would be the oldest and most basal one known, surpassing Raranimus in age by several million years. However, later studies have questioned the placement of Tetraceratops within Therapsida, and the 2009 phylogenetic analysis using Raranimus places the genus outside of the clade.

The Handbook of Birds of the World provisionally lumps all Vanellinae into Vanellus except the Red-kneed Dotterel, which is in the monotypic Erythrogonys. Its plesiomorphic habitus resembles that of plovers, but details like the missing hallux (hind toe) are like those of lapwings: it is still not entirely clear whether it is better considered the most basal plover or lapwing.Piersma & Wiersma (1996), Thomas et al. (2004) Many coloration details of the red-kneed dotterel also occur here and there among the living members of the main lapwing clade.

Brachiosauridae is one of the two major clades of Titanosauriformes, a diverse group of sauropods that existed in the Late Jurassic and Cretaceous in Laurasia and Gondwana. Europasaurus is considered the most basal brachiosaurid. Titanosauriformes was a globally distributed, long-lived clade of dinosaurs that contained both the largest and smallest known sauropods. This clade was composed of three distinct groups: Brachiosauridae, a mix of Late Jurassic and Early Cretaceous sauropods, Euhelopodidae, a group of mid-Cretaceous East Asian sauropods, and Titanosauria, a large Cretaceous clade located mostly in Gondwana.

Anoualerpeton is an extinct genus of lissamphibian in the family Albanerpetontidae. Fossils have been found of two different species in Forest Marble Formation of England, the Kilmaluag Formation of Scotland, and the Ksar Metlili Formation of Morocco dating back to the Bathonian stage of the Middle Jurassic and the Berriasian stage of the Early Cretaceous, respectively. It is thought to be the most basal genus of the Albanerpetontids, and in the case of the species A. unicus, the only albanerpetontid known to have existed in Gondwana.Gardner, J.D., Evans, S.E., and Sigogneau−Russell, D. (2003).

In a 1990 morphological phylogenetic study, Kiyonori Nishida concluded that the deepwater stingray and the sixgill stingray (Hexatrygon bickelli) were the most basal stingrays (suborder Myliobatoidei). Therefore, he moved this species to its own genus, Plesiobatis, and family, Plesiobatidae; the name is derived from the Greek plesio ("primitive") and batis ("ray"). Subsequent morphological studies have corroborated the basal position of Plesiobatis, but disagreed on its relationships to nearby taxa. John McEachran, Katherine Dunn, and Tsutomu Miyake in 1996 could not fully resolve the position of Plesiobatis, thus they assigned it provisionally to the family Hexatrygonidae.

42–57 in D. H. Tanke and K. Carpenter (eds.), Mesozoic Vertebrate Life. Indiana University Press, Indianapolis, Indiana. The earliest and most basal ("primitive") known oviraptorosaurs are Ningyuansaurus wangi, Protarchaeopteryx robusta and Incisivosaurus gauthieri, both from the lower Yixian Formation of China, dating to about 125 million years ago during the Aptian age of the early Cretaceous period. A tiny neck vertebra reported from the Wadhurst Clay Formation of England shares some features in common with oviraptorosaurs, and may represent an earlier occurrence of this group (at about 140 million years ago).

Mosaiceratops is a genus of ceratopsian described by Zheng, Jin & Xu in 2015 found in the Xiaguan Formation of Neixiang County. Although phylogenetic analysis have found it to be the most basal neoceratopsian, the authors noted that several features in the premaxilla and nasal bones are shared with the family Psittacosauridae, indicating that neoceratopsians evolved premaxillary teeth twice and that Psittacosauridae is not a primitive family as previously thought.Zheng, W., Jin, X., & Xu, X. (2015). A psittacosaurid-like basal neoceratopsian from the Upper Cretaceous of central China and its implications for basal ceratopsian evolution.

Early sauropodomorphs such as Massospondylus may have been herbivorous or omnivorous. As recently as the 1980s, paleontologists debated the possibility of carnivory in the "prosauropods". However, the hypothesis of carnivorous "prosauropods" has been discredited, and all recent studies favor a herbivorous or omnivorous lifestyle for these animals. Galton and Upchurch (2004) found that cranial characteristics (such as jaw articulation) of most basal sauropodomorphs are closer to those of herbivorous reptiles than those of carnivorous ones, and the shape of the tooth crown is similar to those of modern herbivorous or omnivorous iguanas.

Ambulocetus swimming The most basal of marine cetaceans, ambulocetids lived in shallow near-shore environments such as estuaries and bays, but were still dependent on fresh water during some stage of their life. Some of the characteristics related to sound transmission found in the lower jaws of modern whales that were absent in pakicetids are present in ambulocetids. They probably swam by paddling their large feet, which is not a very efficient mode of locomotion, suggesting they ambushed rather than chased prey. Ambulocetids had a narrow head with eyes facing laterally.

The phylogenetic relationships among the Stromboidea have been addressed in 2005, by Simone. The author proposed a cladogram (a tree of descent) based on an extensive morpho-anatomical analysis of representatives of Aporrhaidae, Strombidae, Xenophoridae and Struthiolariidae. In his analysis, Simone recognized Strombidae as a monophyletic taxon supported by 13 synapomorphies (traits that are shared by two or more taxa and their most recent common ancestor), with at least eight distinct genera. He considered the genus Terebellum as the most basal taxon, distinguished from the remaining strombids by 13 synapomorphies, including a rounded foot.

When interpreting the ABR, we look at amplitude (the number of neurons firing), latency (the speed of transmission), interpeak latency (the time between peaks), and interaural latency (the difference in wave V latency between ears). The ABR represents initiated activity beginning at the base of the cochlea and moving toward the apex over a 4ms period of time. The peaks largely reflect activity from the most basal regions on the cochlea because the disturbance hits the basal end first and by the time it gets to the apex, a significant amount of phase cancellation occurs.

The only known individual of Eousdryosaurus was a small dryosaurid, estimated at in length, comparable to immature individuals of Dryosaurus and Dysalotosaurus. The right femur measures long and the left shin bone (tibia) measures long. It is differentiated from other dryosaurids by various details of the vertebrae, hip, and hind limb. The foot is unique among ornithopods in that the first digit (the hallux or big toe) includes a single phalanx bone; most basal ornithopods had two phalanges, and most derived ornithopods, including hadrosaurs ("duckbills"), lost this digit.

The olecranon process is well-developed, though it is thin, blade-like, and extends as a crest longitudinally down the shaft of the ulna. In addition, megaraptorids have acquired another long, crest-like structure on the ulna called the lateral tuberosity, which is perpendicular to the blade of the olecranon. As a result, the ulna of megaraptorids is T-shaped in cross section, with three prongs formed by the forward-projection anterior process, the outwards-projecting lateral tuberosity, and the backwards-projecting olecranon process. These adaptations are absent in the most basal megaraptoran, Fukuiraptor.

Claytonia nevadensis is a perennial herb growing from a network of fleshy rhizomes with a small horizontal caudex at ground level. It takes the form of a leafy clump with a stem no longer than about 10 centimeters. The thick red-green leaves are oval to spade-shaped and a few centimeters long, not counting the longer petiole of the most basal leaves. The inflorescence is a dense cluster of 2 to 8 flowers which nests in the clump of leaves or arises on a very short stalk.

The hypothesized relationship among the Euarchontoglires is as follows: One study based on DNA analysis suggests that Scandentia and Primates are sister clades, but does not discuss the position of Dermoptera. Although it is known that Scandentia is one of the most basal Euarchontoglires clades, the exact phylogenetic position is not yet considered resolved, and it may be a sister of Glires, Primatomorpha or Dermoptera or to all other Euarchontoglires. Some recent studies place Scandentia as sister of the Glires, invalidating Euarchonta. Whole-genome duplication took place in the ancestral Euarchontoglires.

Histriasaurus (HIS-tree-ah-SAWR-us) (meaning "Istria lizard") was a genus of dinosaur from the Early Cretaceous (Hauterivian to Barremian stages, around 130 million years ago). Its fossils, holotype WN V-6, were found a bonebed in lacustarine limestone exposed on the seafloor off the coast of the town of Bale on the Istrian peninsula in Croatia, and described in 1998 by Dalla Vecchia. It was a diplodocoid sauropod, related to, but more primitive than, Rebbachisaurus. Phylogenetic analyses published in 2007 and 2011 placed Histriasaurus as the most basal member of Rebbachisauridae.

In 2009, in a molecular phylogenetic study of Malpighiales, Kenneth Wurdack and Charles Davis sampled five genera and one family that had been unplaced in APG II. They placed some of these for the first time and confirmed the previous placement of others with strong statistical support. In their outgroup, they included four genera from Saxifragales. These were Daphniphyllum, Medusandra, Soyauxia, and Peridiscus. In their phylogeny, Medusandra and Soyauxia formed a strongly supported clade with Peridiscus, a member of the family Peridiscaceae, the most basal clade in Saxifragales.

Heterodontosauridae is a family of early ornithischian dinosaurs that were likely among the most basal (primitive) members of the group. Although their fossils are relatively rare and their group small in numbers, they lived across all continents except Australia for approximately 100 million years, from the Late Triassic to the Early Cretaceous. Heterodontosaurids were fox- sized dinosaurs less than in length, including a long tail. They are known mainly for their characteristic teeth, including enlarged canine-like tusks and cheek teeth adapted for chewing, analogous to those of Cretaceous hadrosaurids.

Aspidorhynchus acustirostris, an early teleost from the Middle Jurassic, related to the bowfin The first fossils assignable to this diverse group appear in the Early Triassic, after which teleosts accumulated novel body shapes predominantly gradually for the first 150 million years of their evolution (Early Triassic through early Cretaceous). The most basal of the living teleosts are the Elopomorpha (eels and allies) and the Osteoglossomorpha (elephantfishes and allies). There are 800 species of elopomorphs. They have thin leaf-shaped larvae known as leptocephali, specialised for a marine environment.

Nahuatl forms the most basal clade in Wheeler & Whiteley's (2014) Uto-Aztecan phylogram. A survey of agriculture-related vocabulary by Merrill (2012) found that the agricultural vocabulary can be reconstructed for only Southern Uto-Aztecan. That supports a conclusion that the Proto-Uto-Aztecan speech community did not practice agriculture but adopted it only after entering Mesoamerica from the north. A more recent proposal from 2014, by David L. Shaul, presents evidence suggesting contact between Proto-Uto-Aztecan and languages of central California, such as Esselen and the Yokutsan languages.

Several plesiomorphic (primitive) features characterize Andesaurus as the most basal known member of Titanosauria. In fact, this clade has been defined to contain Andesaurus, Saltasaurus, their most recent common ancestor, and all of its descendants. The most prominent plesiomorphy is the articulations between its tail vertebrae. In most derived titanosaurs, the tail vertebrae articulate with ball-and-socket joints, with the hollowed-out socket end on the front (procoelous caudal vertebrae), while in Andesaurus, both ends of the vertebrae are flat (amphiplatyan caudals), as seen in many non-titanosaurian sauropods.

Dvinosaurs are one of several new clades of Temnospondyl amphibians named in the phylogenetic review of the group by Yates and Warren 2000. They represent a group of primitive semi-aquatic to completely aquatic amphibians, and are known from the Late Carboniferous to the Early Triassic, being most common in the Permian period. Their distinguishing characteristics are a reduction of the otic notch; the loss of a flange on the rear side of the pterygoid; and 28 or more presacral vertebrae. Trimerorhachidae is the most basal family of dvinosaurs.

Assuming Endennasaurus and Askeptosaurus were the most basal askeptosauroids, Askeptosauroidea would have originated in the Western Tethys Ocean, now the Alpine region of Europe. However, if Miodentosaurus is more basal, a Western Tethys (European) origin would be significantly less likely. Although the sister group to Thalattosauria is still debated, one possibility, the icthyosauromorphs, seemingly evolved in the Eastern Tethys (China) during the early Triassic or earlier. The oldest known thalattosauroids (Thalattosaurus, Paralonectes, and Agkistrognathus of British Columbia's Sulphur Mountain Formation) lived in eastern Panthalassa, along what is now the western coast of North America.

Determining the placement of Breviatea and Apusomonadida and their properties is of interest for the development of the opisthokonts in which the main lineages of animals and fungi emerged. The relationships among opisthokonts, breviates and apusomonads are not conclusively resolved (as of 2018), though Breviatea is usually inferred to be the most basal of the three lineages. Ribosomal RNA phylogenies do not usually recover Obazoa as a clade (see for example:), probably reflecting their stemming from a very ancient common ancestor, and little phylogenetic signal remains in datasets consisting of one or a few genes.

Suborder Haplorhini, the simple-nosed or "dry-nosed" primates, is composed of two sister clades. Prosimian tarsiers in the family Tarsiidae (monotypic in its own infraorder Tarsiiformes), represent the most basal division, originating about 58 mya. The earliest known haplorhine skeleton, that of 55 MA old tarsier-like Archicebus, was found in central China, supporting an already suspected Asian origin for the group. The infraorder Simiiformes (simian primates, consisting of monkeys and apes) emerged about 40 mya, possibly also in Asia; if so, they dispersed across the Tethys Sea from Asia to Africa soon afterwards.

Cetiosaurus skeletons have also been found in England, along with the possibly eusauropod genera Cardiodon and Oplosaurus, known only from teeth. The family Mamenchisauridae is found widespread throughout Asia. A majority of the genera are found in China, although a possible specimen of Mamenchisaurus has been found in Thailand. Also in China, the basal eusauropod Nebulasaurus taito was found to be a sister taxon to Spinophorosaurus, and more derived than Mamenchisauridae, but less derived than Patagosaurus, and the genus Shunosaurus is likely one of the most basal eusauropods.

In 2008, Last and William White elevated the kuhlii group to the rank of full genus as Neotrygon, on the basis of morphological and molecular phylogenetic evidence. In a 2012 phylogenetic analysis based on mitochondrial and nuclear DNA, the plain maskray and the Ningaloo maskray (N. ningalooensis) were found to be the most basal members of Neotrygon. The divergence of the N. annotata lineage was estimated to have occurred ~54 Ma. Furthermore, the individuals sequenced in the study sorted into two genetically distinct clades, suggesting that N. annotata is a cryptic species complex.

The lack of osteological information for these species impedes a complete analysis of phylogenetic relationships within the genus. It was hypothesized that L. nematopteryx and L. picinguabae comprise a monophyletic assemblage, given the fact that the pectoral fin of these species consists of a single ray and the ray is in the form of a long filament, a condition not present in any other trichomycterids thus far described. Listura is the most basal member of the subfamily Glanapteryginae; it is sister to a clade formed by the other three genera, Glanapteryx, Pygidianops, and Typhlobelus.

Skeletal diagram of known remains. Alvarezsaurus is considered basal to better-known members of its family, such as Mononykus and Shuvuuia. It has been alternately classified with both non-avian theropod dinosaurs and early birds, but a move of the alvarezsaurids to be recognized as more closely related to neornithine birds proved controversial despite being supported by earlier studies. It was once believed that the Patagonian alvarezsaur taxa were the most basal of their family, but the discovery of a more basal member, Haplocheirus, disproved that when its fossils were discovered in China.

In Jonathan A. Coddington's 2005 summary of the phylogeny and classification of spiders, Dictynoidea has disappeared. Desidae is an "agelenoid"; Dictynidae is the most basal family in the RTA clade; Cybaeidae and Hahniidae are "unplaced families"; Neolanidae (Amphinectidae) is a "stiphidioid". A 2009 "preferred topology" also put genera from Dictynidae at the base of the RTA clade and combined genera from Desidae and Agelenidae into a clade. A 2013 summary, shown below, grouped three members of the classical Dictynoidea into one clade, placing a fourth into another clade, but without naming any of the clades.

Early Cenozoic northern hemisphere paleognaths such as Lithornis, Pseudocrypturus, Paracathartes and Palaeotis appear to be the most basal members of the clade. The various ratite lineages were probably descended from flying ancestors that independently colonised South America and Africa from the north, probably initially in South America. From South America they could have traveled overland to Australia via Antarctica, (by the same route marsupials are thought to have used to reach Australia) and then reached New Zealand and Madagascar via "sweepstakes" dispersals across the oceans. Gigantism would have evolved subsequent to trans-oceanic dispersals.

G. pebasensis was named in 2015 on the basis of a nearly complete skull and several lower jaws from the Pebas Formation near Iquitos in Peru. It lived alongside six other species of crocodylians, including two other caimans with crushing dentitions: Kuttanacaiman iquitosensis and Caiman wannlangstoni. The genus name comes from the Quechua word ñatu meaning "small nose" and the species name comes from an Amazonian village called Pebas. A phylogenetic analysis published alongside its initial description placed Gnatusuchus as the most basal member of the clade Caimaninae.

One major difference includes a midline suture with the nasals that is not present in most burnetiamorphs. The discovery of this fossil is important because it shows that there were two related taxa (Lophorhinus and Lobalopex) alive during the same assemblage zone. The exact relationships within this branch uncertain. The prevailing theory is that Lemurosaurus is the most basal of the three, with Lobaloplex and Lophorhinus being more closely related. Lemurosaurus’ characteristics place it closer to burnetiids than to its biarmosuchian genera, reclassifying them to burnetiamorpha, altering the previous belief that they were in Ictidorhinidae.

The traditional view of hammerhead shark evolution is that species with smaller cephalofoils evolved first from a requiem shark ancestor, and later gave rise to species with larger cephalofoils. Under this interpretation, the winghead shark is the most derived hammerhead, as it has the most extreme cephalofoil morphology. However, molecular phylogenetic research based on isozymes, mitochondrial DNA, and nuclear DNA have found the opposite pattern, with the winghead shark as the most basal member of the hammerhead family. This result supports the counterintuitive idea that the first hammerhead shark to evolve had a large cephalofoil.

Clarke and Norell (2002) found that Apsaravis is the most basal ornithurine bird, but more advanced than Enantiornithes and Patagopteryx. Subsequent cladistic analysis indicates that it and the more advanced Palintropus - long believed to be a modern bird -, and perhaps Ambiortus with which the preceding two had occasionally been allied, form a distinct lineage. This has been named "Palintropiformes", but Apsaraviformes was proposed earlier for the Apsaravis lineage and is thus the senior synonym. And if this group is held to include Apatornis too, it would receive the name Ambiortiformes, which was proposed even earlier.

Chapter on Crassigyrinus from Gaining ground: the origin and evolution of tetrapods, by Jennifer A. Clack, Indiana University Press 2002, from Google Books It was traditionally placed within the group Labyrinthodontia along with many other early tetrapods. Some paleontologists have even considered it as the most basal Crown group tetrapod, while others hesitate to even place it within the Tetrapoda superclass. Crassigyrinus had unusually large jaws, enabling it to eat other animals it could catch and swallow. It had two rows of sharp teeth in its jaws, the second row having a pair of fangs.

Armaniidae was sometimes treated as the most basal of the Formicidae subfamilies, and classed as a stem-group which is more distant in relation to modern ants than the next stem group, Sphecomyrminae. More often the group, treated as "ant-like wasps", was elevated to the rank of family, and considered as a possible sister group to Formicidae. It has been suggested by Engel and Grimaldi that the group may be paraphyletic. This position is in contrast to the original hypothesis of Russian paleoentomologist Gennady Dlussky, who first described the family.

Circinate vernation (the unfolding of new leaves as fiddleheads) is found throughout the lanosa clade and also in M. wrightii, the most basal member of the alabamensis clade. Most species have round rachises, although early-diverging members of the alabamensis and lanosa clades have rachises deeply grooved on the upper surface and flattened rachises shallowly grooved near the frond tip, respectively. Leaf indument (hairs and scales) is highly diverse across the genus and a key feature in species identification. Myriopteris covillei has large, prominent scales beneath the leaf.

Wannia is an extinct genus of basal phytosaur reptile known from the Late Triassic (late Carnian or early Norian stage) of Texas, southern United States. It contains a single species, Wannia scurriensis, which is known from a single specimen. This species was originally named as a species referred to Paleorhinus and later was considered as a possible junior synonym of Paleorhinus bransoni. However its re-description revealed five autapomorphies, and a phylogenetic position as the most basal known phytosaur, justifying the erection of a new generic name for the species.

Spathicephalus was not included in a modern phylogenetic analysis of early tetrapod relationships until the 2000s. In 2009, paleontologists Angela Milner, Andrew Milner, and Stig Walsh incorporated the anatomical characteristics of S. mirus into an analysis of baphetoid interrelationships. The analysis placed Spathicephalus just outside Baphetidae as the sister taxon of the group, a result which they used to justify its placement in a distinct family, Spathicephalidae. The analysis also found Eucritta melanolimnetes, an older species from the Viséan stage of Scotland, to be the most basal member of Baphetoidea.

A differing definition of Herrerasaurus but not Passer domesticus first suggested by Sereno (1998), and more closely follows the original inclusion proposed by Benedetto. Another group, Herrerasauria was named by Galton in 1985, and defined as Herrerasaurus but not Liliensternus or Plateosaurus by Langer (2004), who used the node-based definition for Herrerasauridae. Life restoration In a revision of basal Dinosauria, Padian and May (1993) discussed the definition of the clade, and redefined it as the latest common ancestor of Triceratops and birds. They also discussed what this definition would do to the most basal taxa, such as Herrerasauridae, and Eoraptor.

Stahleckeriid dicynodonts were mostly known from the Late Triassic, and had been suggested to have been a 'slow fuse' lineage that radiated only after the older families of kannemeyeriiforms, such as Kannemeyeriidae and Shansiodontidae, had already gone extinct. As the oldest and possibly most basal member of the family, Ufudocyclops demonstrates that the group had already diversified alongside other kannemeyeriiforms. Nonetheless, Ufudocyclops suggests that stahleckeriids were able to replace other kannemeyeriiforms following local ecological turnovers, at least locally in the Karoo Basin, where it replaced Kannemeyeria after the latter had dominated the preceding Subzone B of the Cynognathus AZ.

Carusioidea is a clade (evolutionary grouping) of lizards that includes the family Xenosauridae (knob-scaled lizards) from Central America and the extinct genus Carusia from the Late Cretaceous of Mongolia. It was named in 1998 after a sister-group relationship was found between Carusia and Xenosauridae. Phylogenetic analysis indicates that Carusioidea is the most basal clade within Anguimorpha. Features that help define Carusioidea include closely spaced orbits or eye sockets separated by fused frontal bones, a connection between the jugal and squamosal bones below the supratemporal arch, and a covering of bony osteoderms over the skull roof.

Ceratopsid skulls at the Natural History Museum of Utah In clade-based phylogenetic taxonomy, Ceratopsia is often defined to include all marginocephalians more closely related to Triceratops than to Pachycephalosaurus. Under this definition, the most basal known ceratopsians are Yinlong, from the Late Jurassic Period, along with Chaoyangsaurus and the family Psittacosauridae, from the Early Cretaceous Period, all of which were discovered in northern China or Mongolia. The rostral bone and flared jugals are already present in all of these forms, indicating that even earlier ceratopsians remain to be discovered. The clade Neoceratopsia includes all ceratopsians more derived than psittacosaurids.

The cinnamon ibon (Hypocryptadius cinnamomeus) is a species of bird endemic to the mountains of Mindanao in the Philippines. Monotypic within the genus Hypocryptadius, it is classified as a sparrow after being tentatively placed in the white-eye family Zosteropidae. Its natural habitat is tropical moist montane forests and mossy forests above . It has a skull and bill similar to that of the sparrows, and following a study of its mitochondrial and nuclear DNA as well as skeletal evidence, Jon Fjeldså and colleagues placed the species as the most basal member of that family and a distinct subfamily.

Recent studies in the ontogeny and evolution of paired appendages have compared finless vertebrates – such as lampreys – with chondricthyes, the most basal living vertebrate with paired fins. In 2006, researchers found that the same genetic programming involved in the segmentation and development of median fins was found in the development of paired appendages in catsharks. Although these findings do not directly support the lateral fin-fold hypothesis, the original concept of a shared median-paired fin evolutionary developmental mechanism remains relevant. A similar renovation of an old theory may be found in the developmental programming of chondricthyan gill arches and paired appendages.

In 1985 the fossil of Iberomesornis was discovered by Armando Díaz Romeral in the Early Cretaceous Calizas de La Huérguina Formation at Las Hoyas, Cuenca Province, east central Spain, which dates to the late Barremian, roughly 125 million years ago. The find was first reported in 1988. In 1992 the type species Iberomesornis romerali was named and described by José Luis Sanz and José Fernando Bonaparte. The generic name is derived from Iberia and Greek μέσος, mesos, "middle", en ὄρνις, ornis, "bird", in reference to the intermediate status between the most basal and the modern birds.

Crassulaceae evolved approximately 100–60 million years ago in southern Africa with the two most basal phylogenetic branches (Crassula, Kalanchoe) representing the predominantly southern African members. Other sources suggest that Crassulaceae evolved approximately 70 million years ago together with Haloragaceae sensu lato (Penthoraceae, Haloragaceae). The family is considered to have had a gradual evolution, with a basal split between Crassuloideae and the rest of the family (Kalanchoideae, Sempervivoideae). The Sempervivoideae subsequently dispersed north to the Mediterranean region, and from there to Eastern Europe and Asia (Sempervivum and Leucosedum clades), with multiple groups spreading over the three continents of the Northern Hemisphere.

Bulletin of Marine Science, 16 (2): 222-229. Phylogenetic analysis based on dentition indicates that the taillight shark is the most basal member of its family and is sister to the clade containing all other dalatiid species. Although no definitive fossil remains have been found, the taillight shark may have evolved in the early Paleocene epoch (65.5-55.8 million years ago - Mya), as part of a larger adaptive radiation of dogfish sharks into midwater habitats. The teeth of the extinct shark Paraphorosoides ursulae, found in early Campanian (83.5-70.6 Mya) deposits in Germany, closely resemble those of the taillight shark.

Following the description of H. bickelli, four additional species of sixgill stingray were described on the basis of morphological differences. However, their validity was brought into question after comparative studies revealed that traits such as snout shape, body proportions, and tooth number vary greatly with age and among individuals. Taxonomists therefore concluded tentatively that there is only a single species of sixgill stingray, though genetic analysis is needed to determine whether this is truly the case. Phylogenetic studies using morphological and genetic data have generally concurred that the sixgill stingray is the most basal member of the stingray lineage.

Evolutionarily, Diadema setosum is considered one of the oldest of the known extant species in the genus Diadema. Genetic analysis of the Diadema have placed D. setosum at a basal branch on a cladogram, having it as the sister group to all the other remaining members of the genus. Morphological analysis confirms this conclusion, adding weight to the concept of D. setosum being the most basal of the Diadema and possibly the oldest extant species in the genus. Like other venomous sea urchins, the venom of Diadema setosum is only mild and not at all fatal to humans.

Phylogenetic analysis suggests that Xingxiulong is most closely related to its contemporary Jingshanosaurus, although an alternative position outside of both the Sauropodiformes and Massospondylidae is also plausible. Despite their close relationship, Xingxiulong prominently differs from Jingshanosaurus - and from most basal sauropodomorphs - in having a number of sauropod-like traits. These include a sacrum containing four vertebrae; a pubis with an exceptionally long top portion; and the femur, the first and fifth metatarsals on the foot, and the scapula being wide and robust. These probably represent adaptations to supporting high body weight, in particular a large gut.

The common name "milk shark" comes from a belief held in India that eating this shark's meat enhances lactation. Other names for this species include fish shark, grey dog shark, little blue shark, Longmans dogshark, milk dog shark, sharp-nosed (milk) shark, Walbeehm's sharp-nosed shark, and white-eye shark. A 1992 phylogenetic analysis by Gavin Naylor, based on allozymes, found that the milk shark is the most basal of the four Rhizoprionodon species examined. The extinct R. fischeuri, known from Middle Miocene (16-12 Ma) deposits in southern France and Portugal, may be the same as R. acutus.

Subsequent evolutionary radiation and speciation has created the diversity of Malagasy lemurs seen today. According to analysis of amino acid sequences, the branching of the family Lemuridae has been dated to 26.1 ±3.3 mya while rRNA sequences of mtDNA place the split at 24.9 ±3.6 mya. The ruffed lemurs are the first genus to split away (most basal) in the family, a view that is further supported by analysis of DNA sequences and karyotypes. Additionally, Molecular data suggests a deep genetic divergence and sister group relationship between the true lemurs (Eulemur) and the remaining three genera: Lemur, Hapalemur, and Prolemur.

The study describing Protodontopteryx notes some "striking" similarities between the jaw structure of Ichthyornithes and pelagornithids. The study still classifies pelagornithids as neognaths based on a few post-cranial features and recovers them in a polytomy with Galloanserae and Neoaves, but does note that this link is worth investigating and that the pelagornithid palate is not known.G. Mayr, V. L. De Pietri, L. Love, A. Mannering, and R. P. Scofield. 2019. Oldest, smallest, and phylogenetically most basal pelagornithid, from the early Paleocene of New Zealand, sheds light on the evolutionary history of the largest flying birds.

The gray fox (Urocyon cinereoargenteus), or grey fox, is an omnivorous mammal of the family Canidae, widespread throughout North America and Central America. This species and its only congener, the diminutive island fox (Urocyon littoralis) of the California Channel Islands, are the only living members of the genus Urocyon, which is considered to be the most basal of the living canids. Though it was once the most common fox in the eastern United States, and still is found there, human advancement and deforestation allowed the red fox to become more dominant. The Pacific States still have the gray fox as a dominant.

Some phylogenetic analyses have placed "Asiatosuchus" germanicus as the sister taxon or closest relative of a group called Mekosuchinae. Mekosuchines are a group of crocodyloids from Australia and the South Pacific that are unusual in that they were highly specialized for life on land. If "A." germanicus is the sister taxon of Mekosuchinae, it may have been close to the ancestry of the group. The earliest known and most basal mekosuchine, Kambara, lived during the same time as Asiatosuchus, suggesting that Asiatosuchus or an Asiatosuchus-like crocodyloid could have dispersed into Australia as the ancestor of mekosuchines.

Its generic name Strigops is derived from the Ancient Greek strix, genitive strigos "owl", and ops "face", while its specific epithet habroptilus comes from habros "soft", and ptilon "feather". The bird has so many unusual features that it was initially placed in its own tribe, Strigopini. Recent phylogenetic studies have confirmed the unique position of this genus as well as the closeness to the kākā and the kea, both belonging to the New Zealand parrot genus Nestor. Together, they are now considered a separate superfamily within the parrots, Strigopoidea, the most basal of all living parrots.

No marine archosaurs like Diandongosuchus and Qianosuchus are known from Europe, although the pseudosuchian Ticinosuchus from Monte San Giorgio was probably adapted to life along the shorelines of the Tethys. In the analyses of Li et al. (2012) and Nesbitt (2011), Ticinosuchus is either the most basal member of a clade called Loricata which is the sister taxon of Poposauroidea, or the sister taxon of Paracrocodylomorpha which includes both Loricata and Poposauroidea. Although Ticinosuchus and Diandongosuchus were initially believed to have been very closely related basal paracrocodylomorphs, this hypothesis is invalidated if Diandongosuchus is a phytosaur as other studies have shown.

More recent phylogenetic analyses that include Nqwebasaurus support its current position as the basalmost member of Ornithomimosauria, one of the most basal clades of Coelurosauria, and the sister taxon of Maniraptora. However, new fossil material of coelurosaurs from the Early Cretaceous of Gondwana is much needed in order to gain a further understanding of Gondwanan coelurosaur phylogeny. The cladogram below follows an analysis by Yuong-Nam Lee, Rinchen Barsbold, Philip J. Currie, Yoshitsugu Kobayashi, Hang- Jae Lee, Pascal Godefroit, François Escuillié & Tsogtbaatar Chinzorig. The analysis was published in 2014, and displays the current phylogenetic position of Nqwebasaurus.

The current taxonomic arrangement of the genus Banksia is based on botanist Alex George's 1999 monograph for the Flora of Australia book series. In this arrangement, B. marginata is placed in Banksia subgenus Banksia, because its inflorescences take the form of Banksia's characteristic flower spikes, section Banksia because of its straight styles, and series Salicinae because its inflorescences are cylindrical. In a morphological cladistic analysis published in 1994, Kevin Thiele placed it as the most basal member of a newly described subseries Integrifoliae, within the series Salicinae. However, this subgrouping of the Salicinae was not supported by George.

Atelestidae is a family of true flies in the superfamily Empidoidea. The four genera were placed in a separate family in 1983;Chvála (1983) they were formerly either in Platypezidae (which are not even particularly closely related) or considered incertae cedis. While they are doubtless the most basal of the living Empidoidea, the monophyly of the family is not fully proven.Moulton & Wiegmann (2007) The genus Nemedina seems to represent a most ancient lineage among the entire superfamily, while Meghyperus is probably not monophyletic in its present delimitation, and it is liable to be split up eventually, with some species being placed elsewhere.

Bauriids belong to a large clade or evolutionary grouping of therapsids called Therocephalia that is closely related to mammals (mammals are part of Cynodontia, the sister taxon of Therocephalia in most studies). Within Therocephalia, bauriids are part of a subgroup called Eutherocephalia, which includes all but the most basal therocephalians. Nested within Eutherocephalia is a clade called Baurioidea, of which bauriids are the most derived members (baurioids that fell outside Bauriidae were traditionally all placed within a group called Scaloposauria, but the group is now thought to be a paraphyletic assemblage of basal baurioids). The inter-group relationships of Bauriidae are uncertain.

However, Matsumoto et al. (2013) places Cteniogenys, the oldest known choristodere, as the most basal member of the group and has Lazarussuchus in a more derived position within a clade of small-bodied choristoderes known mostly from the Early Cretaceous. This position significantly shortens the ghost lineage of Lazarussuchus, although there is still a gap between the disappearance of small-bodied, lizard-like choristoderes at the end of the Early Cretaceous and their reappearance in the form of Lazarussuchus in the Paleocene. Possible lizard-like choristoderes have been found in Late Cretaceous North American deposits, although their remains are very fragmentary.

Their phylogenetic analysis produced the controversial result that Confuciusornis was closer to Microraptor than to Archaeopteryx, making the Avialae a paraphyletic taxon. They also suggested that the ancestral paravian was able to fly or glide, and that the dromaeosaurids and troodontids were secondarily flightless (or had lost the ability to glide). Corfe and Butler criticized this work on methodological grounds. A challenge to all of these alternative scenarios came when Turner and colleagues in 2007 described a new dromaeosaurid, Mahakala, which they found to be the most basal and most primitive member of the Dromaeosauridae, more primitive than Microraptor.

Reconstruction of selected sauropod necks, showing posture and length The skull length of the basal eusauropod, Patagosaurus is about . One of the most basal eusauropods, Shunosaurus, has two characteristic features of the eusauropod elongated neck: the incorporation of the equivalent of the first dorsal vertebra into the cervical region of the spine, and the addition of two cervical vertebra in the middle of the cervical vertebrae. Other synapomorphies of Eusauropoda includes a retracted position of the external nares. Unlike prosauropods and theropods, which have a snout with smooth, unprotruding alveolar and subnarial regions, eusauropods have snouts with “stepped anterior margins”.

Zoologist R. L. Rausch classified the Olympic marmot as the subspecies olympus of Marmota marmota (he included all North American marmots in this species, which now only includes the Eurasian Alpine marmot) in 1953, but it has usually been treated as a distinct species, a classification supported by taxonomic reviews starting with that of zoologist Robert S. Hoffmann and colleagues in 1979. Within Marmota, the Olympic marmot is grouped with species such as the hoary marmot (M. caligata) in the subgenus Petromarmota. Among this grouping, mitochondrial DNA analyses suggest that the Olympic marmot could be the most basal species.

To test the evolutionary relationships of Pravusuchus, Stocker (2010) performed the most inclusive phylogenetic analysis of Phytosauria up to that time. Pravusuchus was coded in the analysis using solely its holotype, as both referred specimen had identical codings for applicable characters. The analysis placed Pravusuchus outside the clade containing species of Mystriosuchus and Pseudopalatus (now Machaeroprosopus), suggesting that it is the sister taxon of Pseudopalatinae. However, to confirm its exclusion from Pseudopalatinae, Nicrosaurus kapffi must be included in the analysis, as Pseudopalatinae is a node-based taxon and Nicrosaurus usually occupies the most basal position in it.

Recent analyses of genetic variation between the ratites do not support this simple picture. The ratites may have diverged from one another too recently to share a common Gondwanan ancestor. Also, the Middle Eocene ratites such as Palaeotis and Remiornis from Central Europe may imply that the "out-of-Gondwana" hypothesis is oversimplified. Molecular phylogenies of the ratites have generally placed ostriches in the basal position and among extant ratites, placed rheas in the second most basal position, with Australo-Pacific ratites splitting up last; they have also shown that both the latter groups are monophyletic.

In traditional schemes, the family Diplomystidae is the basal, primitive sister group to all other catfishes (Siluroidei). This is well supported by morphological evidence. Almost all molecular estimates of catfish phylogeny, by contrast, find Diplomystidae sister to Siluroidei, with Loricarioidei (the armoured catfish and relatives) the most basal group; though this may be an artifact of rapid evolution in loricarioids. Diplomystids retain more plesiomorphic characteristics than any other siluriforms, recent or fossil, including aspects of the maxillary bones, barbels, nares, otic capsule, anterior pterygoid bones, Weberian complex centra, caudal skeleton, and fin rays, and pectoral girdle.

The phylogenetic relationships among the Strombidae have been mainly accessed on two occasions, using two methods. In a 2005 monograph, Simone proposed a cladogram (a tree of descent) based on an extensive morphoanatomical analysis of representatives of the Aporrhaidae, Strombidae, Xenophoridae, and Struthiolariidae. In his analysis, Simone recognized the Strombidae as a monophyletic taxon supported by 13 synapomorphies (traits that are shared by two or more taxa and their most recent common ancestor), comprising at least eight distinct genera. He considered the genus Terebellum as the most basal taxon, distinguished from the remaining strombids by 13 synapomorphies, including a rounded foot.

The three basal most species of the smithii group, B. bilineolata, B. moebiana, and B. smithii have a complex taxonomic history due to their morphological similarities and variations of colour patterns. B. smithii and B. moebiana were initially thought to be varieties of B. bilineolata based on colour pattern. In 1968 Naumann elevated B. bilineolata and B. smithii to species level but still considered B. moebiana as a variety of B. bilineolata. Since then the occipital carina has been used to separate these species and establish B, bilineolata as the most basal species of the smithii group.

Their results were generally similar to previous studies, although notably within Kannemeyeriiformes the family Shansiodontidae was found to be paraphyletic. Ufudocyclops and Stahleckeria were found to be each others closest relatives, sharing at least two characteristics between each other. However, Kammerer and colleagues also identified one feature more like those of earlier kannemeyeriiforms, and found that it was almost as equally plausible that Ufudocyclops could be the most basal species of Stahleckeriinae. This would also be consistent with Ufudocyclops being older than all other stahleckeriines, however, the ancestral appearance of stahleckeriids is poorly understood and so it is unclear whether Ufudocyclops is indeed less derived than Stahleckeria and other stahleckeriines.

Ireangelus is a genus of kleptoparasitic spider wasps from the sub-family Ceropalinae of the family Pompilidae. The genus has a pan tropical distribution,being known from Oriental, Neotropical, Australian, eastern Palearctic, and Madagascan Zoogeographic regions being best represented in the Neotropics. Irenangelus is closely related to the more widespread genus Ceropales, the two genera forming a monophyletic subfamily, Ceropalinae within the Pompilidae. This is regarded as the most basal grouping of the Pompilidae but this view is problematic because of the kleptoparasitic life history of the Ceropalines, it is now considered that they Ceropalines and other pompilids evolved from a common ectoparasitoid ancestor.

Skeletal diagram The braincase of Piatnitzkysaurus has been reviewed in detail by Oliver Rauhut; the review constitutes one of the few detailed accounts of braincase morphology in basal theropods. Piatnitzkysaurusis the only member of Piatnitzkysauridae with cranial material preserved, for which two maxillae, a frontal, a braincase, and a partial dentary are known. Piatnitzkysaurus is among the most basal members of the tetanurans and is important for understanding not only Middle Jurassic theropod evolution in the Southern Hemisphere, but also for knowledge of character evolution at the base of tetanurae. The braincase of the holotype of Piatnitzkysaurus floresi (PVL 4073) is rather well preserved and shows no signs of deformation.

The next closest are the dhole (Cuon alpinus) and African wild dog (Lycaon pictus), which are not members of genus Canis. These are followed by the black-backed and side-striped jackals, members of genus Canis and the most basal members of this clade. Results from two recent studies of mDNA from golden jackals indicate that the specimens from Africa are genetically closer to the gray wolf than are the specimens from Eurasia. In 2015 a major DNA study of golden jackals concluded that the six C.aureus subspecies found in Africa should be reclassified under the new species C.anthus (African golden wolf), reducing the number of golden jackal subspecies to seven.

The mDNA haplotypes of the golden jackal form two haplogroups: the oldest haplogroup is formed by golden jackals from India, and the other, younger, haplogroup diverging from this includes golden jackals from all of the other regions. Indian golden jackals exhibit the highest genetic diversity, and those from northern and western India are the most basal, which indicates that India was the center from which golden jackals spread. The extant golden jackal lineage commenced expanding its population in India 37,000 years ago. During the Last Glacial Maximum, 25,000 to 18,000 years ago, the warmer regions of India and Southeast Asia provided a refuge from colder surrounding areas.

Sphecomyrminae is the most basal of the Formicidae subfamilies, but has not been included in several phylogenetic studies of the family. Symplesiomorphies of the subfamily include the structure of the antenna, which has a short basal segment and a flexible group of segments below the antenna tip. The petiole is low and rounded, with an unrestricted gaster and the presence of a metapleural gland. The subfamily is characterized by three major synapomorphies, the short pedicel, a second flagellar segment that is double the length of the other antenna segments, and the loss of the apical end of the CuA veins in the wings of adult males.

Acerosodontosaurus has generally been considered a "younginiform", part of a paraphyletic grade of Permian diapsids which linked the most basal ("primitive") diapsids (araeoscelidians such as Petrolacosaurus) to more derived ("advanced") diapsids, including the earliest ancestors of modern reptiles such as crocodilians and lizards. However, its position within the grade is controversial. Initially considered a specimen of the contemporaneous Tangasaurus, Acerosodontosaurus was later described as a younginid in 1980 and a tangasaurid in 2009. A 2018 study has even supported a hypothesis that it was not a "younginiform" at all, rather that it was an early member of pantestudines, the reptile lineage that would lead to modern turtles.

Initially considered a specimen of Tangasaurus, Currie (1980) subsequently assigned Acerosodontosaurus to the family Younginidae. The next year, his study of Hovasaurus noted that Acerosodontosaurus shared similarities with both tangasaurids and younginids, and he considered it ancestral to both families. Other studies found a similar result, placing it as the most basal member of "Younginiformes". The 2009 redescription of the genus partially deconstructed the concept of a monophyletic "Younginiformes" and assigned it to Tangasauridae. The 2011 description of the basal neodiapsid Orovenator considered tangasaurids to be stemward (further from modern reptiles) compared to younginids, while a 2016 study of archosauromorphs placed Acerosodontosaurus crownward (closer to modern reptiles) compared to Youngina.

Afrasia djijidae was first described in 2012 on the basis of isolated teeth from the 37-million-year-old Pondaung Formation, which is close to the village of Nyaungpinle in Myanmar. Prior to the discovery of A. djijidae, early Asian simians were typically classified in two families, Eosimiidae and Amphipithecidae. While eosimiids are generally considered the most basal simian clade (a stem group of simians), the phylogenetic placement of amphipithecids is more disputed. Amphipithecids are usually considered to share affinities with either eosimiids or crown simians (those simians that are part of the smallest clade that contains the living simians); the latter view is favored.

This was later revised to the genus Seriolichthys by Bleeker before the species was found to warrant a new genus. The genus Micropteryx was initially created, but was already in use in the Lepidoptera. In 1840, Frederick Debell Bennett created the genus Elagatis, taken from a name published in a whaling voyage memoir, which he used in combination with the specific name bipinnulatus, which was deemed to be incorrect, as the genus name is feminine and the original spelling of bipinnulata was reinstated. Phylogenetically, the species is most closely related to the amberjack genus, Seriola, being the most basal member identified of the carangid tribe Naucratini.

It is listed by the IUCN as least concern, due to its widespread range and adaptability, although it is still persecuted as a livestock predator and rabies vector. Compared to other members of the genus Canis, the black-backed jackal is a very ancient species, and has changed little since the Pleistocene,Kingdon, J. (1977), East African Mammals: An Atlas of Evolution in Africa, Volume 3, Part A: Carnivores, University of Chicago Press, p. 31 being the most basal wolf-like canine, alongside the closely related side-striped jackal. It is a fox-like animalKingdon, J. & Hoffman, M. (2013), Mammals of Africa Volume V, Bloomsbury : London, pp.

In human genetics, Haplogroup G-M285, also known as Haplogroup G1, is a Y-chromosome haplogroup. Haplogroup G1 is a primary subclade of haplogroup G. G1 is possibly believed to have originated in Iran. It has an extremely low frequency in modern populations, except (i) Iran and its western neighbors, and (ii) a region straddling south Central Siberia (Russia) and northern Kazakhstan. The most basal examples of G1 identified in living individuals, which belong to the G-L830 subclade, have been found across an area from the Arabian Peninsula (Northern Borders Region of Saudi Arabia, Ad-Dawhah of Qatar) to Belarus (Minsk Region) and China (Anhui).

Chthonophis (meaning "snake beneath the earth", from the Greek chthonios ("beneath the earth") and ophis ("snake")) is an extinct genus of amphisbaenian lizard with only one known species, Chthonophis subterraneus, from the earliest Paleocene of northeastern Montana. Chthonophis was named in 2015 on the basis of a partial lower jaw from an outcrop of the Fort Union Formation in the Bug Creek Anthills. The surfaces of the bone are well- rounded, suggesting that the remains had been partially digested by another animal before the jaw had been buried and fossilized. Chthonophis is the oldest known amphisbaenian, yet phylogenetic analysis shows that it was not the most basal.

In his 1920 revision, Gilmore argued that the genus was the most basal theropod known from after the Triassic, so not closely related to any other contemporary theropod known at that time; it thus warrants its own family, the Ceratosauridae. It was not until the establishment of cladistic analysis in the 1980s, however, that Marsh's original claim of the Ceratosauria as a distinct group gained ground. In 1985, the newly discovered South American genera Abelisaurus and Carnotaurus were found to be closely related to Ceratosaurus. Gauthier, in 1986, recognized the Coelophysoidea to be closely related to Ceratosaurus, although this clade falls outside of Ceratosauria in most recent analyses.

Most basal dendrites enter the hilus. These hilar dendrites are shorter and thinner, and have fewer side branches. A second excitatory cell type in the hilus is the mossy cell, that projects its axons widely along the septotemporal axis, (running from the septal area to the temporal lobe) with the ipsilateral projection skipping the first 1–2 mm near the cell bodies, an unusual configuration, hypothesized to prepare a set of cell assemblies in CA3 for a data retrieval role, by randomizing their cell distribution. Between the hilus and the granule cell layer is a region called the subgranular zone which is the site of neurogenesis.

Nymphaea alba, from the Nymphaeales The basal angiosperms are the flowering plants which diverged from the lineage leading to most flowering plants. In particular, the most basal angiosperms were called the ANITA grade which is made up of Amborella (a single species of shrub from New Caledonia), Nymphaeales (water lilies, together with some other aquatic plants) and Austrobaileyales (woody aromatic plants including star anise). ANITA stands for Amborella, Nymphaeales and I lliciales, Trimeniaceae-Austrobaileya. Some authors have shortened this to ANA-grade for the three orders, Amborellales, Nymphaeales, and Austrobaileyales, since the order I lliciales was reduced to the family Illiciaceae and placed, along with the family Trimeniaceae, within the Austrobaileyales.

Padian concluded that Dorygnathus after a relatively fast growth in its early years, faster than any modern reptile of the same size, kept slowly growing after having reached sexual maturity, which would have resulted in exceptionally large individuals with a wingspan. On land, Dorygnathus was probably not a good climber; its claws show no special adaptations for this type of locomotion. According to Padian, Dorygnathus, as a small pterosaur with a long tail, was well capable of bipedal movement, though its long metacarpals would make him better suited for a quadrupedal walk than most basal pterosaurs. Most researchers however, today assume quadrupedality for all pterosaurs.

Such studies revealed that Hyracotherium had become a wastebasket taxon of early perissodactyls; many species have now been reassigned to other genera whose exact relationships are not yet resolved. Systemodon has been identified as allied to Cymbalophus and as one of the most basal perissodactyls, making it part of the stem group ancestral to horses, rhinos, tapirs, and the extinct brontotheres and chalicotheres. If Systemodon is a stem perissodactyl, its unusually good preservation gives a rare glimpse into what is basal in the behavior as well as the form of a large group of mammals. Three other species were formerly assigned to this genus: S. semihians, S. protapirinus, and S. primaevus.

The name "phytosaur" means "plant reptile", as the first fossils of phytosaurs were mistakenly thought to belong to plant eaters. The name is misleading because the sharp teeth in phytosaur jaws clearly show that they were predators. For many years, phytosaurs were considered to be the most basal group of Pseudosuchia (crocodile-line archosaurs), meaning that they were thought to be more closely related to the crocodilians than to birds (the other living group of archosaurs). Some recent studies of the evolutionary relationships of early archosauriforms suggest that phytosaurs evolved before the split between crocodile- and bird-line archosaurs and are the sister taxon of Archosauria.

The Cape sparrow was first taxonomically described by Philipp Ludwig Statius Müller in 1776, as Loxia melanura. Some other earlier biologists described the Cape sparrow in Loxia or Fringilla, but it has otherwise been regarded as a member of the genus Passer along with the house sparrow and other sparrows of the Old World. Within this genus, morphological comparisons and geography were insufficient to elucidate to which species the Cape sparrow is most closely related. Mitochondrial DNA phylogenies have strongly suggested that the Cape sparrow is among the most basal members of its genus, having diverged from the rest of the genus during the late Miocene, over 5 million years ago.

Life restoration of Eurypterus. Eurypterus is by far the most well-studied and well-known eurypterid and its fossil specimens probably represent more than 90 % of all known eurypterid specimens. The most basal eurypterines with swimming legs, the genus Onychopterella, are known from the east coast of Gondwana close to the equator (a region that today is South Africa) from the Late Ordovician. It is not known whether or not the swimming forms originated here or not, but it is speculated that they migrated from Laurentia, since most stylonurines and basal swimming forms are predominantly known from Laurentia and Gondwana otherwise completely lacks basal swimming forms.

Nanahughmilleria is placed as the sister taxon of this clade but more basal due to the increased spinosity of its appendage V and in the small size of the genital spatulae. Bassipterus and Pittsfordipterus are positioned as relatively more basal to this clade and form a group supported by two synapomorphies (shared characteristics different from that of their latest common ancestor); long narrow eyes and a complex termination of the genital appendage. At the base of the family, Eysyslopterus has been interpreted as the most basal adelophthalmid. The carapace of this genus, Herefordopterus and Orcanopterus were almost identical and were mainly differentiated by the eye position.

Jamoytius was originally named by Errol White on the basis of two specimens (the generic name is a reference to J. A. Moy-ThomasDawkins, Richard _The Ancestor's Tale_ ) and, at the time, it was considered to be the most basal vertebrate known. Since then, it has been reclassified by many workers as having many different affinities, such as an "unspecialized anaspid", or as a sister taxon to the lampreys, its difficulty in classification due to difficulties in reconstructing the anatomy; it does not possess any usual chordate synapomorphies. Currently, J. kerwoodi is now placed in its own order Jamoytiiformes, together with Euphanerops and similar agnathans.

Brachygastra azteca is considered to be the most basal species, and a sister species to all others in the genus. The rest of the genus Brachygastra has historically been divided into two main groups consisting of closely related species. The lecheguana group consists of B. mellifica, B. lecheguana, and B. borellii, and the smithii group of B. baccalaurea, B. bilineolata, B. smithii, B. propodealis, and B. buyssoni. The scutellaris group, containting B. augusti, B. mouleae, B. fistulosa, B. cooperi, B. myseri and B. scutellaris, is composed of the remaining species that are apparently less closely related and not able to be placed in either of the previous groups.

Diadectids have long been considered close relatives of the amniotes, tetrapods that lay eggs on land or retain the fertilized egg within the mother. In 1987, the paleontologist D.M.S. Watson placed the family in the larger group Diadectomorpha, which includes another family of large-bodied diadectomorphs, the Limnoscelidae, as well as the monotypic diadectomorph family Tseajaiidae, represented by the genus Tseajaia. Throughout the twentieth century, amniotes and diadectomorphs were often grouped together using the old name Cotylosauria, a name originally used for the most basal grade of what was then thought to be reptiles. In the early part of the century, many paleontologists regarded diadectids, along with other cotylosaurs (such as placodonts), to be close relatives of turtles.

Life reconstruction of Eocasea martini Skull Eocasea is the oldest and most basal member of Caseidae, lacking many of the specialized anatomical features that characterize later members of the group. Caseids are notable for being one of the first groups of tetrapods to evolve herbivory; large-bodied taxa such as Casea and Cotylorhynchus have barrel-shaped rib cages and leaf-shaped, serrated teeth that are clear adaptations for breaking down plant cellulose. Eocasea differs from these taxa in having a narrow rib cage, simple cone-shaped teeth, and a much smaller body size. All of these are plesiomorphic features for synapsids, meaning that Eocasea inherited a carnivorous lifestyle from similarly small-bodied carnivorous ancestors of synapsids.

Within the family, a clear division exists between the two subfamilies, the Pseudochelidoninae, which are composed of the two species of river martins, and the Hirundininae, into which the remaining species are placed. The division of the Hirundininae has been the source of much discussion, with various taxonomists variously splitting them into as many as 24 genera and lumping them into just 12. Some agreement exists that three core groups occur within the Hirundininae, the saw-wings of the genus Psalidoprocne, the core martins, and the swallows of the genus Hirundo and their allies. The saw-wings are the most basal of the three, with the other two clades being sister to each other.

Most edopoids are known from the Late Carboniferous and Early Permian of Europe and North America, which at the time formed a larger continent called Euramerica. Procochleosaurus, the oldest edopoid, is known from Ireland, while Edops, the most basal edopoid, is known from the United States, strongly suggesting that the group originated in Euramerica. Tropical and subtropical environments were likely widespread across Euramerica during the Carboniferous and Early Permian, meaning that edopoids could easily travel between what are now North America and Europe. The edopoid Nigerpeton is known from the Late Permian of Africa, extending the time span of edopoids by about 40 million years and expanding their geographic range outside Euramerica.

As current estimates on The male most recent common ancestor ("Y-chromosomal Adam" or Y-MRCA) converge with estimates for the age of anatomically modern humans and well predate the Out of Africa migration, geographical origin hypotheses continue to be limited to the African continent. The most basal lineages have been detected in West, Northwest and Central Africa, suggesting plausibility for the Y-MRCA living in the general region of "Central-Northwest Africa". another study finds a plausible placement in "the north-western quadrant of the African continent" for the emergence of the A1b haplogroup. The 2013 report of haplogroup A00 found among the Mbo people of western present-day Cameroon is also compatible with this picture.

Originally considered by the describers to have been a basal iguanodont, the most basal member of the clade Euiguanodontia. A phylogenetic analysis included in the description of the Antarctic ornithopod Morrosaurus shows that the latter and Gasparinisaura are part of Elasmaria, a clade of iguanodonts known from South America, Antarctica and maybe Australia. Gasparinisaura would be the basalmost member of this group.Sebastián Rozadilla, Federico L. Agnolin, Fernando E. Novas, Alexis M. Aranciaga Rolando, Matías J. Motta, Juan M. Lirio & Marcelo P. Isasi, 2016, "A new ornithopod (Dinosauria, Ornithischia) from the Upper Cretaceous of Antarctica and its palaeobiogeographical implications", Cretaceous Research 57: 311–324 Cladogram based in the phylogenetic analysis of Rozadilla et al.

Pederpes ("Peter's Foot") is an extinct genus of early Carboniferous tetrapod, dating from 348 to 347.6 Ma in the Tournaisian age (lower Mississippian). Pederpes contains one species, P. finneyae, 1 m long. Life reconstruction of Pederpes finneyae This most basal Carboniferous tetrapod had a large, somewhat triangular head, similar to that of later American sister-genus Whatcheeria, from which it is distinguished by various skeletal features, such as a spike- like latissimus dorsi (an arm muscle) attachment on the humerus and several minor skull features. The feet had characteristics that distinguished it from the paddle-like feet of the Devonian Ichthyostegalia and resembled the feet of later, more terrestrially adapted Carboniferous forms.

Similarly, stoneflies retain the most basal traits of the Neoptera, but they were not necessarily the first order to branch off. This also makes it less likely that an aquatic ancestor would have the evolutionary potential to give rise to all the different forms and species of insects that we know today. Dragonfly nymphs have a unique labial "mask" used for catching prey, and the imago has a unique way of copulating, using a secondary male sex organ on the second abdominal segment. It looks like abdominal appendages modified for sperm transfer and direct insemination have occurred at least twice in insect evolution, once in Odonata and once in the other flying insects.

Japanese star anise (Illicium anisatum), from the Austrobaileyales The exact relationships between Amborella, Nymphaeales and Austrobaileyales are not yet clear. Although most studies show that Amborella and Nymphaeales are more basal than Austrobaileyales, and all three are more basal than the mesangiosperms, there is significant molecular evidence in favor of two different trees, one in which Amborella is sister to the rest of the angiosperms, and one in which a clade of Amborella and Nymphaeales is in this position. A 2014 paper says that it presents "the most convincing evidence to date that Amborella plus Nymphaeales together represent the earliest diverging lineage of extant angiosperms". A number of other studies identify Amborella the most basal of all angiosperms.

However, the marginal ornamentation of the telson and the possession of 12-13 gnathobasic (of the gnathobase, a lower appendage used in feeding) teeth in the appendage VI suggests that Herefordopterus was a derived hughmilleriid. In turn, Hughmilleria lacked the marginal ornamentation of the telson and its appendage VI had 18-20 gnathobasic teeth, so it is considered the most basal genus of Pterygotioidea. The triangular anterior carapace margin present in Hughmilleria is shared by the adelophthalmid eurypterid Eysyslopterus, indicating that it might be a plesiomorphic trait (a trait present in a common ancestor). The cladogram presented below, derived from a 2007 study by researcher O. Erik Tetlie, showcases the interrelationships between the pterygotioid eurypterids.

The mantle is pigmented, with a band of increased pigmentation occurring between the area of the right anterior muscle insertion and the posterior pallial edge. The muscular impressions are almost of the same size, with the posterior one rounded and the anterior ones rounded or slightly almond-like. The rachidian tooth has a high base, wider at the most basal portion, and robust but relatively short main cusps, with one to two accessory cusps to their side and, occasionally, an accessory cusp between them. The lateral teeth are tricuspid, the three main cusps being of similar size and having one small accessory cusp between them and one to three to the side of the ectocone.

By the early 21st century, many more therizinosaur taxa had been discovered—including some outside Asia—the first being Nothronychus from North America in 2001. Basal taxa that helped illuminate the early evolution of the group, such as Falcarius in 2005, had also been discovered. Therizinosaurs were no longer considered as rare or aberrant but more diverse in features—including size—than previously thought and their classification as maniraptoran theropods was generally accepted. The placement of Therizinosauria within Maniraptora continued to be unclear; in 2017, Alan H. Turner and colleagues found them to group with oviraptorosaurs while in 2009 Zanno and colleagues found them to be the most basal clade within Maniraptora, bracketed by Ornithomimosauria and Alvarezsauridae.

The presence of a primitive form of tooth development in the most basal osteichthyans sheds light on the manner by which this has evolved. Fossils including those of Andreolepis together with genetic inferences also helped to elucidate the evolution of enamel. The scales of Andreolepis contain the enamel homologue ganoine, but the dermal bones and teeth don’t. Moving up in the phylogenetic tree, more derived extinct and extant species show a shift of enamel-containing structures from the scales, to the dermal plate and eventually the teeth, with enamel lost in dermal teeth-like structures and in some cases even in the teeth of the most derived groups of tetrapods and teleosts.

If Eolambia were to be recognized as a lambeosaurine, then the Lambeosaurinae would have to be redefined to exclude those two traits. Alternatively, if Eolambia was instead the sister group of the Lambeosaurinae, then it would represent a morphology in hadrosaurids that is close to the divergence between hadrosaurines and lambeosaurines. This possibility is supported by the presence of a groove on the bottom of the sacrum of Eolambia, which was recognized by Kirkland as a defining trait of hadrosaurines – albeit one convergently present in the Ankylosauria and Ceratopsia. To support the lambeosaurine affinities of Eolambia, Kirkland conducted a phylogenetic analysis; the tree recovered by his analysis, which accordingly places Eolambia as the most basal lambeosaurine, is reproduced below.

The vertebra was interpreted as the last dorsal vertebra because: its neural spine does not appear to be fused to the neural spine posterior to it, and the usual sacral vertebral count for all but the most basal somphospondylans is six (with seven vertebrae in Neuquensaurus as the only derived exception). Eleven chevrons were listed in the holotype of Huabeisaurus by Pang and Cheng, but thirteen are visible in pre-reconstruction photographs, and twelve are currently present in the Museum of Shijiazhuang University. These elements correspond to positions covering nearly the entire length of the preserved caudal vertebral series. The chevrons are generally well preserved, but there is some distortion and damage.

Stensioella is tentatively placed within Placodermi as being among the most basal of all placoderms, as from what can be discerned from the only whole specimen found, the shoulder joints of its armor appear to be very similar to other placoderms. Despite this detail, coupled with superficial similarities in skull plates, and gross, superficial similarities between its tubercles, and the tubercles of the rhenanids, some paleontologists believe that there are very few concrete reasons for S. heintzi's placement in Placodermi. The paleontologist, Philippe Janvier suggests that it was actually a holocephalid, and not a placoderm at all. However, if this is true, then the holocephalids (chimaeras, iniopterygians, petalodonts, et al.) diverged from sharks before the Chondrichthyan Devonian radiation.

It is characterized by features of the skull, namely of the quadrate and postorbital bones. The vertebral series also has distinctive characters setting it apart from other abelisaurs, such as reduced processes on the cervical vertebrae and dorsal vertebrae lacking pleurocoels. I. aguadagrandensis was considered the most basal abelisaur described at the time, sharing characters, such as an expansion of the postorbital bone above the orbit and a flange of the same bone inside the orbit, with Abelisauridae and Noasauridae; but it was considered to retain primitive features for Abelisauria, such as an opening in the quadrate bone and a T-shaped postorbital. A subsequent analysis has placed it within Abelisauridae, as a brachyrostran carnotaurine.

They share the same habitat and prey species, and form one of the study's 6 identified ecotypes - a genetically and ecologically distinct population separated from other populations by their different type of habitat. The local adaptation of a wolf ecotype most likely reflects the wolf's preference to remain in the type of habitat that it was born into. Wolves that prey on fish and small deer in wet, coastal environments tend to be smaller than other wolves. In 2016, a study of mitochondrial DNA sequences of both modern and ancient wolves generated a phylogenetic tree which indicated that the two most basal North American haplotypes included the Mexican wolf and the Vancouver Island wolf.

Fossil remains of C. adustus date back to the Pliocene era. A mitochondrial DNA sequence alignment for the wolf- like canids gave a phylogenetic tree with the side-striped jackal and the black-backed jackal being the most basal members of this clade, which means that this tree is indicating an African origin for the clade. In 2019, a workshop hosted by the IUCN/SSC Canid Specialist Group recommends that because DNA evidence shows the side-striped jackal (Canis adustus) and black-backed jackal (Canis mesomelas) to form a monophyletic lineage that sits outside of the Canis/Cuon/Lycaon clade, that they should be placed in a distinct genus, Lupulella Hilzheimer, 1906 with the names Lupulella adusta and Lupulella mesomelas.

As suggested in the original description by Myers (2010), the phylogenetic analysis performed by Andres & Myers (2013) recovered A. byrdi as closely related to Pteranodon and the Nyctosauridae. A. byrdi and nyctosaurids were recovered as successive sister groups to the Pteranodontoidea, of which Pteranodon is defined to be the most basal taxon. Although the clade name Pteranodontia usually applies to the clade exclusively formed by pteranodontids and nyctosaurids, it was originally converted by Unwin (2003) to include Pteranodon and Nyctosaurus so under their phylogeny it contains also the Ornithocheirae and other taxa. Therefore, A. byrdi was classified as a non-pteranodontoid pteranodontian, and its sister taxon relationship with Pteranodontoidea warranted the erection of a new genus and species for this material.

Holtz (in 1994) erected the clade Bullatosauria, uniting Ornithomimosauria (the "ostrich-dinosaurs") and Troodontidae, on the basis of characteristics including, among others, an inflated braincase (parabasisphenoid) and a long, low opening in the upper jaw (the maxillary fenestra). Features of the pelvis also suggested they were less advanced than dromaeosaurids. New discoveries of primitive troodontids from China (such as Sinovenator and Mei), however, display strong similarities between Troodontidae, Dromaeosauridae and the primitive bird Archaeopteryx, and most paleontologists, including Holtz, now consider troodontids to be much more closely related to birds than they are to ornithomimosaurs, causing the clade Bullatosauria to be abandoned. One study of theropod systematics by members of the Theropod Working Group has uncovered striking similarities among the most basal dromaeosaurids, troodontids, and Archaeopteryx.

Phlaocyon minor is an extinct species of canid mammal known from the Miocene- Oligocene (Arikareean NALMA, more than ) of the United States (Wyoming, South Dakota, Nebraska, Wyoming, and Texas.) The type specimen of P. minor is a partial maxilla, a partial dentary, and limb fragments found in Oglala Lakota County, South Dakota (: paleocoordinates ). referred half a dozen other specimens to P. minor, including a nearly complete skull and a mandible from Wyoming. P. minor is the most basal member of Phlaocyon but it can still be distinguished from more primitive borophagines such as Archaeocyon, Rhizocyon, and Cynarctoides. Characters placing it in Phlaocyon includes robust and shortened premolars, a quadrate first upper molar, and widened talonid on the first lower molar.

Based on cytochrome b genes, Martin and Naylor (1997) concluded the thresher sharks form a monophyletic sister group to the clade containing the families Cetorhinidae (basking shark) and Lamnidae (mackerel sharks). The megamouth shark (Megachasma pelagios) was placed as the next-closest relative to these taxa, though the phylogenetic position of that species has yet to be resolved with confidence. Cladistic analyses by Compagno (1991) based on morphological characters, and Shimada (2005) based on dentition, have both corroborated this interpretation. Within the family, an analysis of allozyme variation by Eitner (1995) found the common thresher is the most basal member, with a sister relationship to a group containing the unrecognized fourth Alopias species and a clade comprising the bigeye and pelagic threshers.

Other threatened species include two riparian fauna: the threatened California red-legged frog (Rana draytonii) and the western pond turtle (Actinemys marmorata). Pair of gray foxes (Urocyon cinereoargenteus), the only tree-climbing canid in the Americas, den and forage for rodents, grasshoppers and berries near the mouth of Matadero Creek in the Palo Alto Baylands Recently, gray foxes (Urocyon cinereoargenteus) have been documented near the mouth of San Francisquito Creek (see photo) and on the Palo Alto Golf Course. Populations of gray fox have increased in the South Bay since the U.S. Fish and Wildlife Service has culled non-native red foxes (Vulpes vulpes) because the latter prey on the endangered California clapper rail (Rallus longirostris obsoletus). Genetically, gray fox are the most basal of all canids.

Godefroit and colleagues assigned additional remains from the bonebed to their new genus, including three braincases, a cheekbone, two maxillae (the toothbearing bone of the upper jaw), another dentary, two shoulder blades, two sternal elements, two upper arm bones, and an ischium. It can be distinguished from other hadrosaurids by its slender dentary and the unique form of its upper arm, which had distinctive articulations and placements for muscle attachments. Godefroit and colleagues performed a phylogenetic analysis that suggests Wulagasaurus was the most basal saurolophine known (which would result in a long ghost lineage), and interpreted this as evidence that saurolophines and hadrosaurids in general originated in Asia, which has been supported by other finds since. As a hadrosaurid, Wulagasaurus would have been an herbivore.

A search of the scientific literature could not find evidence of hybridization for the rare side-striped jackal. A DNA sequence alignment for the wolf-like canids gave a phylogenetic tree with the gray wolf and dog being the most closely related, followed by a close affiliation with the coyote, golden jackal and Ethiopian wolf, and the dog can hybridize in the wild with these three species. Next closest to this group are the dhole and African wild dog that both have unique meat-slicing teeth, suggesting that this adaptation was later lost by the other members. The two African jackals are shown as the most basal members of this clade, which means that this tree is indicating an African origin for the clade.

Hughmilleriidae (the name deriving from the type genus Hughmilleria, which is named in honor of Scottish geologist Hugh Miller) is a family of eurypterids, an extinct group of aquatic arthropods. The hughmilleriids were the most basal members of the superfamily Pterygotioidea, in contrast with the more derived (more "advanced") families Pterygotidae and Slimonidae. Despite their classification as pterygotioids, the hughmilleriids possessed several characteristics shared with other eurypterid groups, such as the lanceolate telson (the most posterior segment of the body). Hughmilleriids are defined as pterygotioid eurypterids with swimming legs similar to those of the type genus, Hughmilleria (that is, 7th and 8th leg segments narrow and 9th segment very small), and whose second to fifth pair of appendages were spiniferous.

In even the most basal avialian, Archaeopteryx, there is no vestige of the fifth metacarpal and its presence in Protoavis seems incongruous with the claim that it is a bird, let alone one more derived than Archaeopteryx. Chatterjee claims that the humerus of Protoavis is "remarkably avian", but as in all matters with the fossils referred to this taxon, accurate identification of the elaborate trochanters, ridges, etc., attributed to the humerus by Chatterjee is impossible at this time. The expanded distal condyles, which appear to be present in the humerus of Protoavis and enlarged deltopectoral crest (a ridge for the attachment of chest and shoulder muscles), are congruent with the morphology of ceratosaur humeri, as is the apparent presence of a distal brachial depression.

Other common names for this species include banjo shark (not to be confused with the Australian banjo sharks, Trygonorrhina), California thornback, guitarfish, round skate, shovelnose, thornback, and thornback ray. Based on morphology, John McEachran and Neil Aschliman concluded in a 2004 phylogenetic study that Platyrhinoidis and Platyrhina together form the most basal clade of the order Myliobatiformes, and are thus the sister group to all other members of the order (encompassing stingrays and their relatives), rather than being closely related to the true guitarfishes of the family Rhinobatidae, a possibility that had long been considered by taxonomists. Molecular phylogenetics, by contrast, consistently recovers Platyrhinidae as being a close relative of neither guitarfish nor stringrays, but rather as the sister-group to Torpediniformes, the electric rays.

Neornithischia was first named by Cooper in 1985 and defined as "all genasaurians more closely related to Parasaurolophus walkeri Parks, 1922, than to Ankylosaurus magniventris Brown, 1908 or Stegosaurus stenops Marsh, 1877a". A 2017 study by Matthew G. Baron, David B. Norman, and Paul M. Barrett recovered the Early Jurassic taxon Lesothosaurus diagnosticus from Southern Africa as the most basal known member of Neornithischia – a position previously held by Stormbergia dangershoeki (a taxon considered by the authors to be an adult form of Lesothosaurus and therefore a junior subjective synonym). However, Baron et al. go on to state that this result is only poorly supported and that future studies will be needed in order to better resolve the base of the ornithischian tree.

In 2003, Kobayashi and Jun-Chang Lü found that Anserimimus was the sister taxon to Gallimimus, both forming a derived (or "advanced") clade with North American genera, which was confirmed by Kobayashi and Barsbold in 2006. The following cladogram shows the placement of Gallimimus among Ornithomimidae according to Li Xu and colleagues, 2011: Ornithomimosaurs belonged to the clade Maniraptoriformes of coelurosaurian theropods, which also includes modern birds. Early ornithomimosaurs had teeth, which were lost in more derived members of the group. In 2004, Makovicky, Kobayashi, and Currie suggested that most of the early evolutionary history of ornithomimosaurs took place in Asia, where most genera have been discovered, including the most basal (or "primitive") taxa, although they acknowledged that the presence of the basal Pelecanimimus in Europe presents a complication in classification.

Anomocephaloidea is a clade (evolutionary grouping) of anomodont therapsids that existed in Gondwana during the Middle Permian and includes two species, Anomocephalus africanus from South Africa and Tiarajudens eccentricus from Brazil, both of which are characterized by large body size and teeth that fit tightly together or occlude. Anomocephaloidea is among the most basal groups of anomodonts, the other being Venyukovioidea, which differs in being a Laurasian clade of mostly small-bodied species. Anomocephaloidea was named in 2011 with the discovery of Tiarajudens; Anomocephalus had been known since 1999, but was unique among anomodonts until Tiarajudens was described. Both Anomocephalus and Tiarajudens were herbivores, although the latter possessed a pair of saber-like canine teeth that may have been used in display or combat with other individuals of the same species.

Early bony fishes (~420 mya) had two pair of nostrils, one pair for incoming water (known as the anterior or incurrent nostrils), and a second pair for outgoing water (the posterior or excurrent nostrils), with the olfactory apparatus (for sense of smell) in between. In the first tetrapodomorphs (~415 mya) the excurrent nostrils migrated to the edge of the mouth, occupying a position between the maxillary and premaxillary bones, directly below the lateral rostral (a bone that vanished in early tetrapods). In all but the most basal (primitive) tetrapodomorphs, the excurrent nostrils have migrated from the edge of the mouth to the interior of the mouth. In tetrapods that lack a secondary palate (basal tetrapods and amphibians), the choanae are located forward in the roof of the mouth, just inside the upper jaw.

2009 skeletal reconstruction of Mahakala as a generic deinonychosaur A phylogenetic analysis performed by Turner and colleagues, who described the specimen, found Mahakala to be the most basal known dromaeosaurid. Their results, along with the small size of other theropods found at the base of paravian lineages, suggest that small size was not an innovation of early birds, but a common trait of early paravians; small size would have preceded flight and would not have been a special avian autapomorphy as the result of a size squeeze. Like birds, troodontids and dromaeosaurids were not small throughout their evolutionary history, and showed size increases among several different lineages. Mahakala has a combination of characteristics found among basal troodontids and birds, but lacks some that are present in more derived dromaeosaurids.

Members of this genus inhabit coastal sites and build silken cells which they seal at high tide; however, they do not balloon. DNA sequence analysis suggests that ancestors of the genus dispersed from southern South America to South Africa about 10 million years (Ma) ago, where the most basal clade is found; subsequent rafting events then took the genus eastward with the Antarctic Circumpolar Current to Australia, then to New Zealand and finally to Chile by about 2 Ma ago. Another example among spiders is the species Moggridgea rainbowi, the only Australian member of a genus otherwise endemic to Africa, with a divergence date of 2 to 16 Ma ago. However, oceanic dispersal of terrestrial species may not always take the form of rafting; in some cases, swimming or simply floating may suffice.

The discovery of Ciurcopterus, the most primitive known pterygotid, and studies revealing that Ciurcopterus combines features of Slimonia (the appendages are particularly similar) and of more derived pterygotids, revealed that the Slimonidae was more closely related to the Pterygotidae than the Hughmilleriidae was, establishing Hughmilleriidae as the most basal group of pterygotioid eurypterids. The family has been recovered as paraphyletic in a number of phylogenetic analyses and does thus not form an actually valid scientific grouping. Nevertheless, the family is retained and routinely used by eurypterid researchers. Within the family, both genera shared several characteristics such as the carapace being much broader anteriorly than posteriorly, appendages II-V being spiniferous (possessing spines), swimming legs similar to those of Hughmilleria itself, the slight enlargement of their chelicerae and their small and streamlined bodies.

They also concluded Faxinalipterus is the most basal known pterosaur, basal features including a lack of fusion between tibia and fibula, a thin radius and a coracoid that has not fused to the scapula. However, Alexander Kellner has suggested Faxinalipterus might be not be a pterosaur but a basal member of the Pterosauromorpha instead or, if the lack of fusion between tibia and fibula is plesiomorphic, even a sister taxon of the Ornithodira. Fabio Marco Dalla Vecchia (2013) stated that he was "unable to find any unequivocal pterosaur features" in the known fossils of F. minima; in fact, according to the author, "the purported humerus is quite unlike the humeri of the Triassic pterosaurs". Dalla Vecchia did not consider Faxinalipterus to be a pterosaur, but did not state what group of vertebrates it belonged to.

Left maxilla Life restoration Size compared to a human The holotype skeleton, MNN GAD1, includes a maxilla (main tooth-bearing bone of the upper jaw), vertebrae, ribs, and articulated pelvic girdle and sacrum, belonging to an adult about . According to the describers, this specimen represents one of the earliest known abelisaurids, and is notable for the heavily textured surface of the maxilla; the presence of pits and impressions of blood vessels indicates that there was a covering firmly attached to the face, perhaps of keratin. Sereno and Brusatte performed a cladistic analysis that found Kryptops to be the most basal abelisaurid. This was based on several features, including a maxilla textured externally by impressed vascular grooves and a narrow antorbital fossa, that clearly place Kryptops palaios within Abelisauridae as its oldest known member.

How exactly the tree swallow is related to other members of Tachycineta is unresolved. In studies based on mitochondrial DNA, it was placed basal (meaning it was the first offshoot in the species tree) within the North American-Caribbean clade consisting of the violet-green swallow, golden swallow, and Bahama swallow. Although mitochondrial DNA is advocated as a better indicator of evolutionary changes because it evolves quickly, analyses based on it can suffer because it is only inherited from the mother, making it worse than nuclear DNA from multiple loci at representing the phylogeny of a whole group. A study based on such nuclear DNA placed the tree swallow in the most basal position within Tachycineta as a whole (as a sister group to the rest of the genus).

Within Hughmilleriidae, both genera possessed a marginal rim much broader anteriorly than posteriorly and appendages spiniferous of Hughmilleria-type, but Hughmilleria had 18-20 gnathobasic (of the gnathobase, a lower appendage used in the alimentation) teeth on appendage VI, unlike Herefordopterus and the pterygotids, who had 12-13. Therefore, Hughmilleria represents the most basal form of Pterygotioidea. According to Clifton J. Sarle, Hughmilleria was very similar to Eurypterus, and could be confused with a species of this genus if it was not for the presence of the marginal position of the eyes and the relatively large chelae. However, by its cordate metastoma, the intramarginal to marginal position of the compound eyes, the slightly longer preoral appendages, less developed swimming legs and the opercular appendage, Hughmilleria was more like Pterygotus.

A cladistic analysis by the describers showed Feilongus as the sister taxon of a clade consisting of Gallodactylus and Cycnorhamphus, meaning it was a member of the Gallodactylidae sensu Kellner, a group of ctenochasmatoids, within the larger Archaeopterodactyloidea, the clade containing according to Alexander Kellner the most basal pterodactyloids. The Ctenochasmatoidea are known for having numerous small, thin teeth, possibly for straining food from water, as flamingos do today. However, in 2006 an analysis by Lü Junchang had as outcome that Feilongus was not an archaeopterodactyloid, but a member of the Ornithocheiroidea sensu Kellner, closer to the Anhangueridae. This means that using the alternative terminology of David Unwin they are close to the Ornithocheiroidea sensu Unwin, a group the members of which are typically more adapted to soaring and a piscivore, or fish-eating, diet.

Early to late Olenekian trackways from Poland have yielded footprints of a Lagerpeton-like quadrupedal dinosauromorph. This ichnogenus, named Prorotodactylus shares multiple synapomorphic characters with Lagerpeton including approximately parallel digits II, III and IV, fused metatarsus, digitigrade posture and reduced digits I and V. Prorotodactylus also shares the, previously autapomorphic, pes morphology of Lagerpeton. If this ichnogenus represents a close relative of Lagerpeton, it would push back the origin of this taxon to the Early Triassic; as a quadrupedal basal dinosauromorph, it also raises questions debating the theory that bipedalism is ancestral to dinosaurs. The genus Lagerpeton is currently accepted as the most basal clade within Dinosauromorpha and the sister taxon to Dinosauriformes. Presently, Lagerpeton sits within the family “Lagerpetidae”, also occupied by the more derived genus Dromomeron, known from Late Triassic rocks of the southwestern USA.

Culebrasuchus was first described and named by Alexander K. Hastings, Jonathan I. Bloch, Carlos A. Jaramillo, Aldo F. Rincona and Bruce J. Macfadden in 2013 based on a single holotype skull and three neck vertebrae from the Culebra Formation. Culebrasuchus is thought to be the most basal member of Caimaninae, meaning that it represents the earliest radiation of caimans in the Americas. The ancestor of Culebrasuchus likely lived farther north, perhaps in what is now southern Mexico, because before the Miocene most of Panama was underwater. The movement of Culebrasuchus into the Panama Canal Zone was an early part of the Great American Interchange in which animals dispersed between North and South America across the newly formed Isthmus of Panama (although during the Early Miocene it had not yet formed, with 20 km of ocean still separating the continents).

Diagram of the holotype The authors who initially described the fossil, classified Eshanosaurus as a member of the Therizinosauroidea on the basis of six distinct characteristics of the jaw and teeth, making it the earliest known coelurosaur, a maniraptoran living long before Archaeopteryx, 60 million years before certain basal therizinosaurs such as Falcarius and Beipiaosaurus. A cladistic analysis was not performed and the authors "speculatively" suggested it was the most basal known therizinosauroid. Due to the unusually long chronological gap in the therizinosauroid and coelurosaurian fossil record or ghost lineage created by this interpretation of the find, a few scientists have expressed doubts about the classification of Eshanosaurus as a therizinosauroid. James Kirkland and D.G. Wolfe, in their 2001 paper describing the therizinosaur Nothronychus, related personal correspondence that the teeth of Eshanosaurus bore a medial ridge only seen in prosauropods or basal Sauropodomorpha.

More generally, the proavians would, in view of their basal theropod forebears and bird descendants, have been typified by long necks, a short trunk, long fingers with opposable digits, a decoupling of the locomotor functions of the forelimbs and hindlimbs, a lack of a propatagium, a shallow tail, and a weight of about one kilogramme. Paul illustrated his analysis with a skeletal diagram, accompanied by a life illustration of a "proavis".Paul, G.S., 2002, Dinosaurs of the Air: The Evolution and Loss of Flight in Dinosaurs and Birds, Johns Hopkins University Press, 473 pp When Aurornis was described in 2013, it was at the time the most basal known member of the Avialae, the group consisting of birds and their closest relatives. The Italian paleontologist Andrea Cau remarked it bore an uncanny resemblance to Paul's "proavis".

As Rüppell did not originally designate a holotype, in 1960 a 31-cm-long specimen caught off Jeddah, Saudi Arabia, was made the species lectotype. Other common names for this shark include blunthead shark, light-tip shark, reef whitetip shark, and whitetip shark. Once placed in the family Triakidae, the whitetip reef shark is now recognized by most authors as belonging to the family Carcharhinidae on the basis of morphological characters, such as a full nictitating membrane, well-developed precaudal pit, strong lower caudal fin lobe, and scroll-like intestinal valves. Morphological and molecular phylogenetic analyses suggest the whitetip reef shark is grouped with the lemon sharks (Negaprion) and the sliteye shark (Loxodon) in occupying an intermediate position on the carcharhinid evolutionary tree, between most basal genera (Galeocerdo, Rhizoprionodon, and Scoliodon) and the most derived (Carcharhinus and Sphyrna).

Some further diagnostic characters unite the group, such as the slightly enlarged chelicerae (frontal appendages) and the streamlined shape of their bodies. The family contains only two genera, Hughmilleria and Herefordopterus, though other genera have been referred to the family in the past, such as genera now considered part of families such as the Mycteroptidae and the Waeringopteridae. The hughmilleriids were the most basal group of pterygotioid eurypterids, lacking the derived features that would come to evolve in the Slimonidae and Pterygotidae, such as flattened and expanded telsons (the posteriormost segment of the body, this feature is shared by both derived families) and enlarged cheliceral claws (exclusive to the pterygotids). In spite of the great similarity of both genera, Herefordopterus had derived characteristics that suggest a close relationship with Slimonidae and Pterygotidae, such as the marginal ornamentation of the telson.

Overlooking the naming of Titanosauria, Paul Upchurch in 1995 named the clade Titanosauroidea, to include Opisthocoelicaudia and the more derived Titanosauridae (Malawisaurus, Alamosaurus and Saltasaurus). United by: caudals with anteriorly-shifted neural spines, extremely robust forearm bones, a prominent concavity on the ulna for articulation with the humerus, a laterally flared and flattened ilium, and a less robust pubis; Upchurch considered the clade sister taxon to Diplodocoidea, because of their shared dental anatomy, although he noted that peg-like teeth might have been independently evolved. This was followed up by Upchurch's 1998 study on sauropod phylogenetics, which additionally recovered Phuwiangosaurus and Andesaurus within Titanosauroidea and resolved Opisthocoelicaudia as the sister of Saltasaurus instead of the most basal titanosauroid. This result places Titanosauroidea in a group with Camarasaurus and Brachiosaurus, although Nemegtosauridae (Nemegtosaurus and Quaesitosaurus) was still classified as the basalmost family of diplodocoids.

This individual would have measured approximately 29 cm (11 in) in length in life. Kjellesvig-Waering noted that the species did not resemble any of the other North American species of Pterygotus that had been described but that it did share some similarities with the British P. anglicus, from which it could still be differentiated by the different shape of the carapace, differences in the sixth appendage and P. ventricosus exhibiting a greater gibbosity. In 2007, O. Erik Tetlie and Derek E. G. Briggs redescribed the species based on four new specimens recovered from Kokomo. The new material allowed them to determine that P. ventricosus represented the most basal pterygotid eurypterid and the study helped provide evidence for the precise phylogenetic position of the family, showing that the Slimonidae (and not the Hughmilleriidae) was the most closely related group to the Pterygotidae.

They published the first ever cladogram showing the evolutionary relationships of Therizinosauria, and demonstrated that Beipiaosaurus had features of more basal theropods, coelurosaurs, and therizinosaurs. By the early 21st century, many more therizinosaur taxa had been discovered, including outside Asia (the first being Nothronychus from North America), as well as various basal taxa that helped understanding of the early evolution of the group (such as Falcarius, also form North America). Therizinosaurs were not considered as rare or aberrant anymore, but more diverse than previously thought (including in size), and their classification as maniraptoran theropods was generally accepted. The placement of Therizinosauria within Maniraptora continued to be unclear; in 2017, paleontologist Alan H. Turner and colleagues found them to group with oviraptorosaurs, while Zanno and collagues found them to be the most basal clade within Maniraptora in 2009, bracketed by Ornithomimosauria and Alvarezsauridae.

The sicklefin lemon shark may also be referred to as broadfin shark, Indian lemon shark, Indo-Pacific lemon shark, or simply lemon shark. Based on microsatellite DNA evidence, the sicklefin lemon shark is thought to have diverged from its sister species N. brevirostris 10-14 million years ago, when the closure of the Tethys Sea separated lemon sharks in the Indian Ocean from those in the Atlantic. The ancestral lemon shark species may have been N. eurybathrodon, the fossilized teeth of which occur in both the United States and Pakistan. Morphological and molecular phylogenetic analyses suggest that Negaprion is grouped with the whitetip reef shark (Triaenodon) and the sliteye shark (Loxodon) in occupying an intermediate position on the carcharhinid evolutionary tree, between the most basal genera (Galeocerdo, Rhizoprionodon, and Scoliodon) and the most derived (Carcharhinus and Sphyrna).

A mitochondrial DNA (mDNA) sequence alignment for the wolf- like canids gave a phylogenetic tree with the side-striped jackal and the black-backed jackal being the most basal members of this clade, which means that this tree is indicating an African origin for the clade. Because of this deep divergence between the black-backed jackal and the rest of the "wolf- like" canids, one author has proposed to change the species' generic name from Canis to Lupulella. In 2017, jackal relationships were further explored, with an mDNA study finding that the two black-backed jackal subspecies had diverged from each other 1.4 million years ago to form the central African and east African populations. The study proposes that due to this long separation, which is longer than the separation of the African golden wolf from the wolf lineage, that the two subspecies might warrant separate species status.

No unambiguously paleognathous fossil birds are known until the Cenozoic (though birds occasionally interpreted as lithornithids occur in Albian appalachian sitesPalaeogene Fossil BirdsA lithornithid (Aves: Palaeognathae) from the Paleocene (Tiffanian) of southern California ), but there have been many reports of putative paleognathes, and it has long been inferred that they may have evolved in the Cretaceous. Given the northern hemisphere location of the morphologically most basal fossil forms (such as Lithornis, Pseudocrypturus, Paracathartes and Palaeotis), a Laurasian origin for the group can be inferred. The present almost entirely Gondwanan distribution would then have resulted from multiple colonisations of the southern landmasses by flying forms that subsequently evolved flightlessness, and in many cases, gigantism. Pseudocrypturus cercanaxius fossil cast, Copenhagen Zoological Museum One study of molecular and paleontological data found that modern bird orders, including the paleognathous ones, began diverging from one another in the Early Cretaceous.

Based on what is known of Gorgodon—the squamosal, quadrate, and pterygoid bones of the back of the skull, the maxilla and premaxilla bones that make up the front of the skull, and several teeth—Gorgodon had a relatively large temporal fenestra and a pair large, conical caniniform teeth at the front of the jaw. Other distinguishing features of Gorgodon include the fused connection between the quadrate and squamosal bones and a long transverse process of the pterygoid (a projection extending from the pterygoid bone on the underside of the skull). Olson classified Gorgodon as a very early therapsid because it had a heterodont dentition and large temporal fenestra not seen in the most basal synapsids but present in therapsids. He placed it in the family Phthinosuchidae because its teeth seemed similar to those of Phthinosaurus, an enigmatic therapsid from the Middle Permian of Russia that is most likely a dinocephalian.

Reisz (1972) tentatively classified Echinerpeton as an ophiacodontid in its initial description, but later (1986) considered it an indeterminate "pelycosaur". Lee (1999) argued that the placement of Echinerpeton within Synapsida was not certain because it lacked any of the defining features or synapomorphies present in the group, all of which come from the skull. He claimed that all the features linking Echinerpeton with synapsids were also present in other basal amniotes, so it could not be placed definitively on the synapsid branch of Amniota (the other amniote branch is Sauropsida, or reptiles). Benson (2012) was the first to include Echinerpeton in a phylogenetic analysis, and considered it a "wildcard taxon" because it had three equally likely positions on the synapsid tree: one as the most basal synapsid, another as the sister taxon of a clade containing Caseasauria, Edaphosauridae, and Sphenacodontia, and a third as an ophiacodontid more derived than Archaeothyris.

They also assigned Biseridens to a distinct new family of eotitanosuchians, the Biseridensidae, although they did not provide a diagnosis for this family outside of the genus itself. Although relatively primitive, a number of shared traits (synapomorphies) ally Biseridens with anomodonts including the shortened snout, raised zygomatic arch and exclusion of the septomaxilla between the maxilla and nasals. However, it retains a number of primitive traits that exclude it from the more derived anomodonts, including the differentiated tooth row, palatal teeth, contact between tabular and opisthotic; lateral process of transverse flange of pterygoid free of posterior ramus and absence of mandibular foramen. Several cladistic analyses indicate that Biseridens is the most basal anomodont known, including that of Liu and colleagues (2009) shown below, as well as those of Cisneros and colleagues (2011) and Kammerer and colleagues (2013): The most recent analysis performed by Liu et al.

Counter slab of the holotype, on display at the Geological Museum of China Feduccia's frill argument was followed up in several other publications, in which researchers interpreted the filamentous impressions around Sinosauropteryx fossils as remains of collagen fibres rather than primitive feathers. Since the structures are clearly external to the body, these researchers have proposed that the fibres formed a frill on the back of the animal and underside of its tail, similar to some modern aquatic lizards. The absence of feathers would refute the proposal that Sinosauropteryx is the most basal known theropod genus with feathers, and also raise questions about the current theory of feather origins itself. It calls into question the idea that the first feathers evolved not for flight but for insulation, and that they made their first appearance in relatively basal dinosaur lineages that later evolved into modern birds.

Matadero Creek at Hillview Road, Palo Alto, with Great Blue Heron Three gray foxes (Urocyon cinereoargenteus), the only tree-climbing canid in the Americas, den and forage for rodents, grasshoppers, and berries near the mouth of Matadero Creek in the Baylands View of Interstate 280 from the Matadero Creek Trail, which crosses the hill between Matadero Creek and its Deer Creek tributary Recently, gray fox (Urocyon cinereoargenteus) have been documented near the mouth of Matadero Creek (see photo). Populations of gray fox have increased in the South Bay since the U.S. Fish and Wildlife Service has culled non-native red fox (Vulpes vulpes) because the latter prey on endangered California clapper rail (Rallus longirostris obsoletus). Genetically, gray fox are the most basal of all canids. Steelhead trout (Oncorhynchus mykiss) were supported by Matadero Creek historically, and at least as recently as the late 1980s.

Feathers, originally serving the insulation of an already warm-blooded animal, would by elongation have turned the arms into wings in order to fly. More generally, the proavians would, in view of their basal theropod forebears and bird descendants, have been typified by long necks, a short trunk, long fingers with opposable digits, a decoupling of the locomotor functions of the forelimbs and hindlimbs, a lack of a propatagium, a shallow tail, and a weight of about one kilogramme. Paul illustrated his analysis with a skeletal diagram, accompanied by a life illustration of a "proavis".Paul, G.S., 2002, Dinosaurs of the Air: The Evolution and Loss of Flight in Dinosaurs and Birds, Johns Hopkins University Press, 473 pp When in 2013 Aurornis was described, at the time the most basal known member of the Avialae, the group consisting of birds and their closest relatives, the Italian paleontologist Andrea Cau remarked it bore an uncanny resemblance to Paul's "proavis".

In 2017, American paleontologists Stephen Brusatte and Thomas D. Carr published a new phylogenetic analysis of Tyrannosauroidea, including a more comprehensive suite of anatomical characteristics and taxa, that disagreed with the results of Loewen and colleagues. While the tribe Alioramini was outside Tyrannosauridae in the analysis by Loewen and colleagues, Brusatte and Carr placed that group as the most basal (early-diverging or "primitive") group within Tyrannosaurinae. Conversely, Loewen and colleagues found Bistahieversor to be a derived ("advanced") tyrannosaurine closely related to the likewise derived Teratophoneus and Lythronax, while Brusatte and Carr placed it in a more basal position directly outside Tyrannosauridae, with both Teratophoneus and Lythronax as basal tyrannosaurines. It was suggested that both of these results stemmed from an over-weighting of some features by Loewen and colleagues, which resulted in the long-snouted alioramin forms being excluded from the short-snouted tyrannosaurines, and the placement of Bistahieversor and Lythronax closer to Tyrannosaurus than otherwise.

Biseridens ("two rows of teeth") is an extinct genus of anomodont therapsid, and one of the most basal anomodont genera known. Originally known from a partial skull misidentified as an 'eotitanosuchian' in 1997, another well- preserved skull was found in the Xidagou Formation, an outcropping in the Qilian Mountains of Gansu, China, in 2009 that clarified its relationships to anomodonts, such as the dicynodonts. Among tetrapod taxa, the therapsid clade anomodontia in which Biseridens belong has one of the largest population sizes, highest levels of diversity, and longest stratigraphic range (Middle Permian to the Triassic, possibly into the Cretaceous), as well as being one of the only clades known from all the continents. Primarily understood from the recently discovered, most-well preserved specimen, Biseridens is most notably distinguishable as an anomodont due to its short snout, dorsally elevated zygomatic arch, and presence of a septomaxilla that distinctly lacks a facial exposure between the nasal and maxilla.

Dunkleosteidae is an extinct family of arthrodire placoderms. The gigantic apex predator Dunkleosteus terrelli is the best known member of this group. While they were previously thought to be close relatives of the genus Dinichthys (when they were not synonymized as each other) and grouped together in the family Dinichthyidae, more recent studies have shown that the two taxa represent two very distinct clades within Arthrodira. The reappraisal of Kiangyousteus lead to a restructuring of the family, with the inclusions of the benthic, aberrant Heterosteus (and the other members of Heterosteidae) as the sister taxon of Dunkleosteus, and the Late Emsian Xiangshuiosteus as the sister taxon of Eastmanosteus calliaspis (with the direct implication that E. calliaspis does not belong in Eastmaneosteus), and the removal of Westralichthys from the family (now thought to be the most basal member of the superfamily Dunkleosteoidea, and sister taxon of Panxiosteidae and Dunkleosteidae)Zhu, You‐An, and Min Zhu.

Restoration of the primitive Cambrian arachnomorph Fuxianhuia, one of the most basal members of the lineage that would eventually lead to both the chelicerates and the trilobites. A phylogenetic analysis (the results presented in a cladogram below) conducted by James Lamsdell in 2013 on the relationships within the Xiphosura and the relations to other closely related groups (including the eurypterids, which were represented in the analysis by genera Eurypterus, Parastylonurus, Rhenopterus and Stoermeropterus) concluded that the Xiphosura, as presently understood, was paraphyletic (a group sharing a last common ancestor but not including all descendants of this ancestor) and thus not a valid phylogenetic group. Eurypterids were recovered as closely related to arachnids instead of xiphosurans, forming the group Sclerophorata within the clade Dekatriata (composed of sclerophorates and chasmataspidids). Lamsdell noted that it is possible that Dekatriata is synonymous with Sclerophorata as the reproductive system, the primary defining feature of sclerophorates, has not been thoroughly studied in chasmataspidids.

Eutitanosauria was proposed as a name for the titanosaurs more derived than Epachthosaurus, and noted the presence of osteoderms as a probable synapomorphy of this clade. Aeolosaurus, Alamosaurus, Ampelosaurus and Magyarosaurus were looked at using their character list, but were considered too incomplete to add to the final study. Argentinian paleontologist Jaime Powell published his 1986 thesis in 2003, with revisions to bring his old work up to date, including the addition of more phylogenetics and the recognition of Titanosauria as a clade name. Using the datamatrix of Sanz et al. (1999) and modifying it to include additional taxa and some character changes, Powell found that titanosaurs formed mostly a single gradual radiation beginning with Epachthosaurus as the most basal titanosaur, and Ampelosaurus and Isisaurus as the most derived. Titanosauroidea (following Upchurch 1995), was distinguished by pre- and post- spinal laminae in anterior caudals, a laterally flared ilium, a lateral expansion of the upper femur, and strongly opisthocoelous posterior dorsals.

In fact, the most basal species of the clade so far (Eysyslopterus patteni) has been recovered from Ludlovian (around 427-423 mya) deposits of the paleocontinent Baltica (Scandinavia and Eastern Europe, precisely Estonia). However, it is not possible to determine where the clade originated, probably in Baltica or Laurentia (most of eastern continental North America). Although most of the representatives of Adelophthalmoidea have been found in Laurentia, Avalonia (Germany, Great Britain, parts of eastern North America) and Baltica (that is, Laurussia), the nearly cosmopolitan (worldwide) genus Adelophthalmus was also present in the Rheno-Hercynian Terrane (western and central Europe), Siberia and in the Gondwana part of the current Australia. In the Silurian, most of the adelophthalmid genera would appear, but all went extinct soon after or in the Middle Devonian. The oldest representatives of the group were Parahughmilleria maria and Nanahughmilleria prominens, both from the Llandovery (around 444-433 mya), suggesting that the adelophthalmids first appeared around this epoch.

By the early 21st century, the prevailing theories were that the family was the sister group of either the Marginocephalia (which includes pachycephalosaurids and ceratopsians), or the Cerapoda (the former group plus ornithopods), or as one of the most basal radiations of ornithischians, before the split of the Genasauria (which includes the derived ornithischians). Heterodontosauridae was defined as a clade by Sereno in 1998 and 2005, and the group shares skull features such as three or fewer teeth in each premaxilla, caniniform teeth followed by a diastema, and a jugal horn below the eye. In 2006, palaeontologist Xu Xing and colleagues named the clade Heterodontosauriformes, which included Heterodontosauridae and Marginocephalia, since some features earlier only known from heterodontosaurs were also seen in the basal ceratopsian genus Yinlong. Timelapse video showing the construction of a model built around a skull cast, including musculature Many genera have been referred to Heterodontosauridae since the family was erected, yet Heterodontosaurus remains the most completely known genus, and has functioned as the primary reference point for the group in the palaeontological literature.

The hypothesis asserts that as organismal and social complexity grows, the need to preserve the fundamental structure of an organism – the most basal directions involved in the most basic development and functions which mutate more slowly – becomes balanced against the need to be able to adapt to increasing numbers of environmental pressures and challenges – done by faster-mutating regions that respond adaptively to environmental pressures. The hypothesis states that the variability in the rate of change causes evolutionary selective pressures to sort alleles into two rough groups: slow-mutating ones involved with an organism's most basic structure and function, and fast-mutating ones that respond quickly in order to increase the odds a beneficial mutation occurs and is preserved. As time passes and a species increases in complexity, it is theorized that a greater proportion of its genome becomes slow-mutating as a greater amount of information becomes needed to preserve a more complex organism's fundamental development and behavior. And with a larger proportion of its genome dedicated to intrinsic instructions, the species is considered to be more genetically fragile.

Several authors, such as Siewin (1963), believe that the Syncarida is the most basal group due to the absence of morphological traits that are present in the remaining eumalacostracans; in addition, the Syncarida are distributed worldwide in reclusive habitats such as interstitial and groundwater, whereas their extensive fossil record shows that they were once marine, implying that the species present today are remnants of a more abundant group. A second problematic group often attributed to be basal in the Eumalacostraca clade is the Hoplocarida. This group is composed of 200 species commonly called mantis shrimps, which are found in shallow tropical and subtropical marine habitats that have adapted to a predatorial life thanks to their specialized large second pair of thoracopods (thoracic appendices), raptorial legs, which are used to capture prey, in fact their name is a combination of Greek words meaning “armed shrimp”. Its precise location amongst the Malacostraca is unclear and has been proposed to be a sister group to the remaining eumalacostracans due to its ancient fossil record but it has also been placed either sister to the Eucarida or even inside the Eucarida by molecular studies.