Maxillary breathing valves in the sharks Chlamydoselachus and Cetorhinus with notes on breathing valves in thirteen marine teleosts

• Published in: Journal of Morphology
• Main Author: Gudger, E. W.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 1935
• Subjects: Cetorhinus maximus
• Online Access: http://dx.doi.org/10.1002/jmor.1050570105; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fjmor.1050570105; https://onlinelibrary.wiley.com/doi/pdf/10.1002/jmor.1050570105

Abstract Chlamydoselachus anguineus has, extending across the upper front mouth just behind the origin of the rear teeth of each row, a shelf of tissue forming a functional breathing valve. Valves of three types were found in five specimens. One has the hinder edge crescentic, another is like the head of a ‘broad arrow,’ and the third is intermediate in outline. A similar valve, crescentic in outline has been found in the upper front mouth of a 13‐foot specimen of Cetorhinus maximus dissected in the American Museum. Breathing valves are briefly described in thirteen marine teleosts at Tortugas, Florida. Some fishes had only maxillary valves, some mandibular, and a few had both. These consist of thin folds of tissue which swing back and forth as the fish breathes. A brief summary is given of breathing valves in other teleosts and in sharks and rays. The function of breathing valves in fishes is to prevent regurgitation of water during expiration as the fish swims along with partly open mouth. It is also correlated with feeding where the food is impaled on the teeth and held for swallowing, or where the fish feeds on pelagic organisms collected by swimming along with open mouth.