Comparative anatomy, homologies and evolution of mandibular, hyoid and hypobranchial muscles of bony fish and tetrapods: A new insight

The Osteichthyes, including bony fishes and tetrapods, is a highly speciose group of vertebrates, comprising more than 42000 living species. The anatomy of osteichthyans has been the subject of numerous comparative studies, but these mainly concern osteological structures; much less attention has been paid to muscles. In fact, the most detailed and comprehensive myological comparative analyses that were actually based on a direct observation of representatives of various major osteichthyan groups were provided various decades by authors such as Luther, Kesteven and principally Edgeworth. The present work provides an updated discussion of the homologies and evolution of the osteichthyan mandibular, hyoid and hypobranchial muscles, based on the author's own analyses and on a survey of the literature, both old and recent. The risks of discussing muscle homologies on the basis of a single line of evidence, even when it concerns innervation or development, is emphasized. It is stressed than only by taking into consideration various lines of evidence (e.g. developmental biology, comparative anatomy, functional morphology, paleontology, molecular biology, experimental embryology, innervation and/or phylogeny) it is possible to establish well-grounded hypotheses of muscle homology.