Double trachea in penguins and sea lions

Vocal tract anatomy of king penguins: morphological traits of two-voiced sound production

“…Furthermore, as this coupling process happens for the two voices F01 and F02 on each side of the king penguin syrinx separately, the STM could function as a "barrier", preventing F01 and F02 from mixing for most of the length of the trachea. Tracheal septa have been reported to be present in little penguins [66], African penguins [37], dugongs Dugong dugon [49], and leatherback turtles [50]). Reports on leatherback turtle and dugong vocalisations are scarce and provide little or no evidence for individual vocal signatures (leatherback turtles [67,68], dugongs [69]).…”

“…Favaro et al [36] used computational models of African penguin vocal tracts and showed that the difference between air resonance in a single versus a two-tube model was related to a variation in formant position and dispersion. However, the authors simplified their model assuming that "the trachea is divided by a septum for all its length", which is not the case, neither in African [49] nor in king penguins. Still, formant frequencies have been shown to be individually distinct and might encode individual identity, e.g.…”

“…Watson [48] described the tracheal septum as being present in Procellariidea, but not in the Southern rockhopper penguin Eudyptes chrysocome or the Little penguin Eudyptula minor. Zeek [49] investigated the vocal apparatus of African penguins and confirmed the presence of the septum calling it a "double trachea". Despite the presence in some penguin species, king and emperor penguins A. forsteri have been reported to "appear" to have no tracheal septum [50].…”

A tracheal septum during routine pre-operative work-up

“…To our knowledge, a tracheal septum or double trachea has never been reported in humans, however, it has been reported previously in penguins and sea lions. [1] In the event of a tracheal septum being encountered during intubation, the plan (dependent on the level of the tracheal septum and its structure) was to attempt intubation as normal if possible or intubation of one or both lumens of the tracheal septum with smaller endo-tracheal tubes. However, his intubation demonstrated a…”

The anatomical record under the sea: A history of reporting findings on the biology, adaptations, and evolution of mammals that inhabit a watery world

“…This journal has long been a leader in uncovering the anatomy and function below the waves and, indeed, some of our brightest lights have put their scalpels and microscopes to the task. Particularly notable in this regard have been the following: the elegant and insightful comparative studies by George B. Wislocki, renown Professor and Chair of Anatomy at Harvard Medical School (and the mentor and stimulator of many anatomists, such as Editor Emeritus of this journal, John Ladman) on the hypophysis in mysticete whales (Wislocki and Geiling, 1936), on comparisons of the hypophysis among elephants, manatees, and hyraxes (Wislocki, 1940), on the ovary of humpback whales (Demsey and Wislocki, 1941), and on the lungs in porpoises (Wislocki, 1942); studies by the Chinese anatomist Chi Ping, on the visceral and testicular anatomy of the Yangtze River porpoise (Ping, 1926a,b); a study by one of the greatest embryologists of his day, Leslie B. Arey, on the seal liver (1932); the work by Oldham and colleagues on the hypophysis of the manatee (Oldham et al, 1938); the comparative study by Grafflin and Geiling on the thyroid gland in whales (1942); studies on the anatomy and physiology of the reproductive system of fur seals by Enders, Pearson, and colleagues (Enders et al, 1946;Pearson and Enders, 1951); the study by Zeek on the fascinating occurrence of the double trachea in penguins and sea lions (Zeek, 1951); the comparative study on cardiac anatomy, pathology, and coronary circulation of whales by the eminent anatomist Raymond C. Truex (Truex et al, 1961); work by the Japanese anatomist Kinziro Kubota on the variation in dentition among pinnipeds (Kubota and Togawa, 1964) and on the comparative anatomy of the fur seal tongue (Kubota, 1968); the exquisitely detailed study by Galliano and colleagues on the cervicothoracic arterial system of the bottlenose dolphin (1966); the study by Sinha and Conaway on the ovary of the sea otter (1968); Morita and colleagues examination of the carotid body in the weddel seal (1970); comparative studies on the arteriovenous anastomoses in the skin of seals by Molyneux and Bryden (1978;Bryden and Molyneux, 1978); the study by noted Yale orthopedist John Ogden and colleagues on the cervical spine in pilot whales (1981); and the series of studies by Haldiman, Henk, Abdelbaki, and colleagues on the respiratory system and other features of the rare bowhead whale (Henry et al, 1983;Abdelbaki et al, 1984;Haldiman et al, 1984Haldiman et al, , 1985Henk and ...…”