Cochran and Goin (1970) were unaware of the identities of Hyla verrucigera and riopastazae; they used the later name Osteocephalus orcesi for Colombian frogs that are correctly referred to O. verrucigerus. Although Goin (1961) placed Hyla buckleyi and H. pearsoni in Osteocephalus, Cochran and Goin (1970) recognized a "buckleyi group" in Hyla that included these two species plus a new species, Hyla cabrerai from Amazonian Colombia and Brasil (total of three specimens). Also, these authors named Hyla carri from a single Colombian specimen. Study of the types of Hyla cabrerai, H. carri, and H. festae Peracca, 1904, from Ecuador, reveal that all of these names are synonyms of Osteocephalus buckleyi.
Much of the taxonomic confusion and multiplicity of trivial names is due to the great amount of color variation in taurinus and to the sexual dimorphism in the texture of the dorsal skin in all of the species. The details of variation in these and other characters and our justifications for the synonymies are given in the accounts of the species. All of the trivial names that apply to species herein recognized as members of the genus Osteocephalus are listed in [table 1].
Osteocephalus Steindachner, 1862
Osteocephalus Steindachner, 1862:77 [Type species.—Osteocephalus taurinus Steindachner, 1862, by original designation]. Not Osteocephalus Fitzinger, 1843:50 (nomen nudum).
Diagnostic Definition.—1) Skull broader than long; 2) dermal roofing bones of skull well ossified, exostosed, and/or co-ossified in some species; 3) prenasal and internasal bones absent; 4) parasphenoid alae posterolaterally oriented; 5) dentigerous processes of prevomers angular (/— —\); 6) vocal sacs paired, posterior, and when inflated protruding posteroventral or posterolateral to angles of jaws; 7) submentalis muscle moderate in size and araphic; 8) intermandibularis muscle undifferentiated and bearing an elongate median aponeurosis; 9) parotoid glands absent or poorly developed, skin not producing viscous secretion characteristic of Phrynohyas; 10) skin on dorsum tuberculate in males, smooth in females; 11) tympanum large, 60 percent or more of diameter of eye; 12) fingers about one-third, toes more than three-fourths webbed; 13) discs large, round; 14) nuptial excrescences present in breeding males; 15) inner metatarsal tubercle not modified for digging; 16) outer metatarsal tubercle absent; 17) tarsal fold weak or absent; 18) pupil horizontal; 19) palpebrum clear; 20) known tadpoles having two upper and five lower rows of teeth.
Table 1.—Alphabetical Synonymy of the Species of Osteocephalus.
| Trivial Name, Original Generic Name, Author, Date | Current Name |
| britti (Hyla leprieurii) Melin, 1941 | O. leprieurii |
| buckleyi (Hyla) Boulenger, 1882 | O. buckleyi |
| cabrerai (Hyla) Cochran and Goin, 1970 | O. buckleyi |
| carri (Hyla) Cochran and Goin, 1970 | O. buckleyi |
| depressa (Hyla) Andersson, 1945 | O. taurinus |
| festae (Hyla) Peracca, 1904 | O. buckleyi |
| flavolineatus (Osteocephalus) Steindachner, 1862 | O. taurinus |
| leprieurii (Hyla) Duméril and Bibron, 1841 | O. leprieurii |
| orcesi (Hyla) Funkhouser, 1956 | O. verrucigerus |
| pearsoni (Hyla) Gaige, 1929 | O. pearsoni |
| planiceps (Osteocephalus) Cope, 1874 | O. taurinus |
| riopastazae (Hyla) Andersson, 1945 | O. verrucigerus |
| taurinus (Osteocephalus) Steindachner, 1862 | O. taurinus |
| verrucigera (Hyla) Werner, 1901 | O. verrucigerus |
| vilarsi (Hyla) Melin, 1941 | O. taurinus |
Content.—As defined here, the genus contains five known species: O. buckleyi (Boulenger), O. leprieurii (Duméril and Bibron), O. pearsoni (Gaige), O. taurinus Steindachner, and O. verrucigerus (Werner).
Distribution.—The Guianas and Amazon Basin; also in the upper Orinoco and Magdalena drainages. Most localities are at elevations below 500 m, but the genus ascends the Amazonian slopes of the Andes to elevations of about 1800 m.
Analysis of Characters