ABSTRACT
This chapter analyzes the mandibular, hyoid, branchial, and hypobranchial muscles of the three extant amphibian taxa: salamanders (Caudata or Urodela), frogs (Anura), and caecilians (Gymnophiona). New information has become available about the ontogeny of the cephalic muscles in representatives of each of these amphibian groups, which is particularly useful for the analysis of the homologies of these muscles within these groups. The adductor mandibulae A2, the adductor mandibulae A2-PVM, and the pseudotemporalis are included in the so-called adductor mandibulae complex of amphibians, which is often named "levator mandibulae complex". Several urodele and some anuran and caecilian amphibians have an interhyoideus anterior and an interhyoideus posterior, which is often named "interbranchialis" or "sphincter colli". Amphibians and amniotes have multiple hypobranchial muscles. The amphibian muscles geniohyoideus, genioglossus, and hyoglossus probably derive from the coracomandibularis of sarcopterygian fishes, while the sternohyoideus and omohyoideus derive from the sternohyoideus of these fishes.
