ABSTRACT
This chapter is concerned with the mandibular, hyoid, branchial, and hypobranchial muscles of actinopterygians and basal sarcopterygians. It explains Edgeworth's hypotheses regarding the respective plate and discusses the extent to which they are supported by work. The discussions and hypotheses are based on evidence from developmental biology, comparative anatomy, functional morphology, paleontology, experimental embryology and molecular biology, and innervation and phylogeny. The chapter illustrates the risks of discussing the homologies of structures such as muscles on the basis of a single line of evidence, even if it concerns innervation or development. However, they also illustrate that it is possible to establish well-grounded hypotheses of homology when multiple lines of evidence are available and taken into consideration (such as developmental biology, comparative anatomy, functional morphology, paleontology, experimental embryology, innervation, and/or phylogeny).
