Cope (1878) proposed the genus _Syrrhophus_ for a medium-sized leptodactylid frog from central Texas; in the ensuing 75 years the genus was expanded to include a heterogeneous group of frogs ranging from Texas to Peru. Taylor (1952) and Firschein (1954) limited the genus to several species of frogs occurring in Guatemala, México, and Texas. Lynch (1968) provided a definition of the previously loosely-defined genus.

With the exception of Taylor (1952), who treated the Costa Rican species, none of these authors dealt with the present status of the nineteen species erroneously assigned to _Syrrhophus_. These species are listed in Tables 1 and 2 with the name currently applied. Some of them are new combinations and their justifications will be published elsewhere. Gorham (1966) is the most recent author to include South American species in the genus _Syrrhophus_.

Smith and Taylor (1948) recognized two species groups of the genus in México, an eastern and a western group (here termed complexes for purposes of discussion), separated on the basis of the number of palmar (metacarpal) tubercles (three palmar tubercles in the members of the eastern complex and two in those of the western complex). Duellman (1958) reviewed the species of the genus occurring in western México and concluded that there were five species (two polytypic). Dixon and Webb (1966) described an additional species from Jalisco, México. The distributions of some species have been extended, but otherwise the western complex of species remains unchanged since Duellman’s review.

Smith and Taylor (1948) recognized seven species of the genus in eastern México. Firschein revised the eastern complex (as then understood), and in so doing added one new species and treated _Syrrhophus verruculatus_ as a _nomen dubium_. Dixon (1957) redefined the related genus _Tomodactylus_ and transferred _T. macrotympanum_ Taylor to the genus _Syrrhophus_. Neill (1965) described a new subspecies of _S. leprus_ from British Honduras. Two species (_S. gaigeae_ and _S. marnockii_) were recognized in Texas until Milstead, Mecham, and McClintock (1950) synonymized _S. gaigeae_ with _S. marnockii_. Thus, at present, nine species (one polytypic) are recognized on the eastern slopes and lowlands from central Texas to British Honduras. These are currently placed on one species group equivalent to the western complex reviewed by Duellman (1958).