Tendons of Jaw Muscles in Amphibia and Reptilia: Homology and Evolution

Nikolai N. Iordansky


Patterns of the tendinous skeleton of jaw muscles in various groups of Amphibia and Reptilia are considered. In the jaw adductors of amphibians there are three basic systems of tendons: coronar, subarticular and pterygoidal (the latter only in the Gymnophiona). In reptiles the tendinous framework of jaw muscles is more developed. In the diapsid Reptilia the quadrate tendinous system appears, and the subarticular one is completed by retroarticular aponeurosis. Evolution and homology of tendinous structures are discussed in connection with these of the jaw adductor muscles. The anterio-medial sheet of coronar aponeurosis and the subarticular aponeurosis inhere in the internal jaw adductor, while oilier parts of coronar aponeurosis are usually connected with the external one. The M. pterygoideus anterior of the crocodilians inserts onto the anterio-medial sheet of the coronar aponeurosis and seems to be homologous with the M. pseudotemporalis of other reptiles. The general pattern of the jaw adductor tendons of the Ophidia may be derived from that of the Gekkota, while the pattern of the Amphisbaenia from that of the Autarchoglossa.


tendons; jaw muscles; homology; evolution; Amphibia; Reptilia

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