Because preserved syrinxes are rare in the fossil record, the origin of this anatomical innovation has been a longstanding mystery for paleontologists.
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For instance, the fact that no syrinxes have been found in non-avian dinosaur fossils of the same age as Vegavis iaai suggests that this might be an adaptation that is unique to birds.
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He said that although the research does not completely rule out the possibility that nonavian dinosaurs had these organs, the finding might encourage more researchers to be on the lookout for syrinxes in the fossil record.
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By analyzing the structure of the organ with X-ray computed tomography and cross-referencing it with the syrinxes of 12 living birds, Clarke and her co-authors were able to narrow down the properties of the extinct bird's bygone song.
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The most specialised bills of any storks are those of the two openbills (Anastomus.), which as their name suggested is open in the middle when their bill is closed. These bills have evolved to help openbills feed on their only prey item, aquatic snails. Although it is sometimes reported that storks lack syrinxes and are mute, they do have syrinxes, and are capable of making some sounds, although they do not do so often. The syrinxes of the storks are "variably degenerate" however, and the syringeal membranes of some species are found between tracheal rings or cartilage, an unusual arrangement shared with the ovenbirds.
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At least ½ of syrinxes occur in patients with congenital abnormalities of the craniocervical junction (e.g. herniation of cerebellar tissue into the spinal canal, called Chiari malformation), brain (e.g. encephalocele), or spinal cord (e.g. myelomeningocele—see Congenital Neurologic Anomalies: Brain Anomalies).
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Not all dogs with SM have clinical signs. The presence of signs is correlated to the width of the syrinx and extent of spinal cord dorsal horn damage. Syrinxes can progressively expand and a dog which is asymptomatic in early life may eventually experience pain.
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Syringobulbia is a medical condition in which syrinxes, or fluid-filled cavities, affect the brainstem. This defect normally results from congenital abnormality, trauma or tumor growth. It mostly occurs within the lower brainstem as a slit-like gap. This may affect one or more cranial nerves, resulting in various kinds of facial palsies.
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Other symptoms may include headaches and a loss of the ability to feel extremes of hot or cold, especially in the hands. Each patient experiences a different combination of symptoms. These symptoms typically vary depending on the extent and, often more critically, to the location of the syrinx within the spinal cord. Syrinxes usually result from lesions that partially obstruct CSF flow.
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Syringomyelia (SM) is a condition affecting the brain and spine, causing symptoms ranging from mild discomfort to severe pain and partial paralysis. It is caused by a malformation, commonly known as Chiari Malformation, in the lower back of the skull which reduces the space available to the brain, compressing it and often forcing it out (herniating it) through the opening into the spinal cord. This blocks the flow of cerebral spinal fluid (CSF) around the brain and spine and increases the fluid's pressure, creating turbulence which in turn is believed to create fluid pockets, or syrinxes (hence the term syringomyelia), in the spinal cord. Syringomyelia is rare in most breeds but has become widespread in the Cavalier King Charles Spaniel, with international research samples in the past few years consistently showing over 90% of Cavaliers have the malformation, and that between 30–70% have syrinxes.
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Ochre-rumped antbird calling Song of the barred antshrike The songs and calls of antbirds are generally composed of repeated simple uncomplicated notes. The family is one of the suboscines (suborder Tyranni) which have simpler syrinxes ("voiceboxes") than other songbirds. Nevertheless, their songs are distinctive and species-specific, allowing field identification by ear. Antbirds rely on their calls for communication, as is typical of birds in dark forests.
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Cysts known as syrinxes can affect the brainstem, in a condition, called syringobulbia. These fluid-filled cavities can be congenital, acquired or the result of a tumor. Criteria for claiming brainstem death in the UK have developed in order to make the decision of when to stop ventilation of somebody who could not otherwise sustain life. These determining factors are that the patient is irreversibly unconscious and incapable of breathing unaided.
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However, most dogs with syrinxes are not symptomatic. Although symptoms of syringomyelia can present at any age, they typically appear between six months and four years of age in 85% of symptomatic dogs, according to Clare Rusbridge, a research scientist. Symptoms include sensitivity around the head, neck, or shoulders, often indicated by a dog whimpering or frequently scratching at the area of his neck or shoulder. Scratching is often unilateral – restricted to one side of the body.
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The only other member of the subfamily is the white-eyed river martin Pseudochelidon sirintarae, known only from one site in Thailand and possibly extinct. These two species possess a number of features which distinguish them from other swallows and martins, including their robust legs and feet, stout bills, large syrinxes (vocal organs) and different bronchial structure. Genetic studies confirmed that the two river martins form a distinct clade from the typical swallows in the subfamily Hirundininae. The two river martins are in some ways intermediate between typical swallows and other passerine birds, and the arrangement of their leg muscles is more like that of a typical passerine than of a swallow.
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They use the "mouths" to manipulate objects, as a humanoid uses hands. The Puppeteer's native language sounds like highly complex orchestral music, but they seem to be able to reproduce human language without difficulty or device, as well as the Heroes' Tongue (Kzinti), suggesting their vocal arrangement may resemble a pair of avian-like syrinxes rather than vocal cords. Biologically, Puppeteers are highly intelligent herbivores; a herd animal, Puppeteers prefer the company (and smell) of their own kind. Their cycle of reproduction is similar to that of Earth's digger wasps: the Puppeteers consider themselves to have three genders (two male, one female): the two "male" genders are the equivalent of human female and male (one has an ovipositor, the other produces sperm) and the "female" is a (non- sentient) parasitized host into which the ovum and spermatozoon are deposited.
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