John D. Lynch

“ The major problem for students working with the Mexican leptodactylids has not been the separation of Engystomops or Leptodactylus from other genera but the separation and definition of the eleutherodactyline frogs currently placed in three genera, Eleutherodactylus, Syrrhophus, and Tomodactylus. As will be shown in this paper, these are more conveniently placed in four genera. Once a fourth genus is recognized, certain phylogenetic problems disappear and a reasonable zoogeographic interpretation is possible for Middle American leptodactylid distribution. ”

“ At least nine leptodactylid genera are either known or thought to be terrestrial breeders lacking a free-living tadpole stage (Eleutherodactylus, Euparkerella, Hylactophryne, Niceforonia, Noblella, Sminthillus, Syrrhophus, Tomodactylus and Trachyphrynus) . Niceforonia and Trachyphrynus, and probably Hylactophryne, are not closely related to the other genera. Direct development probably is an adaptation to adverse environmental conditions since many of the species occur in semi-arid or cold (Andean páramos) areas. ”

“ Supernumerary tubercles rarely are present on the feet of Eleutherodactylus, but are present and numerous in every species of Syrrhophus, Tomodactylus, and in the members of the augusti group of Eleutherodactylus (Fig. 3) . The tubercles are small and numerous in Syrrhophus and larger in Tomodactylus and the Eleutherodactylus augusti group. Most species of Eleutherodactylus have no plantar supernumerary tubercles; a few species have such tubercles, which never extend between the metatarsal tubercles as in Syrrhophus and Tomodactylus. ”