In their account of Osteocephalus leprieurii, Cochran and Goin (1970:323) stated: "The specimen described and illustrated (MCZ 28042) has been directly compared with the types of leprieurii, planiceps, and vilarsi by the junior author and there seems to be no doubt that all are conspecific. Another specimen (CNHM 69716) has been directly compared with the types of planiceps and vilarsi and these, likewise, are considered conspecific." With this justification Cochran and Goin (1970:322) included Osteocephalus planiceps Cope, 1874, and Hyla vilarsi Melin, 1941, in the synonymy of Osteocephalus leprieurii.
We do not concur with Cochran and Goin's synonymy and contend that planiceps and vilarsi are synonyms of Osteocephalus taurinus; we give our reasons in the account of that species. We have examined the specimens listed as O. leprieurii by Cochran and Goin; several of them, including CNHM (= FMNH) 69716, are taurinus. Thus, due to Cochran and Goin's confusion of two taxa, their comparisons of certain specimens with types has little meaning.
Cochran and Goin did not include Hyla leprieurii britti in their synonymy of Osteocephalus leprieurii but did discuss the name in their account of Osteocephalus orcesi (= O. verrucigerus), as follows (1970:319): "When we first examined one of the specimens we felt sure that we had Melin's Hyla britti at hand, but on direct comparison with the type of britti the two proved to be different. After studying the type of orcesi (SUNHM 13150) we have no doubt that the specimens at hand are orcesi and that britti is a different, probably valid species."
Diagnosis.—1) Size moderate, sexual dimorphism evident; maximum observed snout-vent length in males 48.4 mm, in females, 61.5 mm; 2) skin on dorsum in males bearing numerous, minute, spinous tubercles; 3) skin on flanks smooth; 4) web extending to base of antepenultimate phalange on inner edge of third finger; 5) dorsum tan or olive-brown with transverse brown or olive bars; 6) venter creamy white or pale tan without markings; 7) lips marked with creamy tan labial stripe and suborbital spot; 8) flanks pale tan with no markings; 9) dermal roofing bones of skull lacking exostosis; 10) dermal sphenethmoid absent; 11) nasals juxtaposed medially; 12) anteromedial margin of frontoparietal between mid- and anterior levels of orbit; 13) frontoparietal fontanelle partially exposed; 14) palatine not serrate; 15) parasphenoid lacking odontoids; 16) zygomatic ramus of squamosal extending about one-half of distance to maxillary arch; 17) transverse processes of presacral vertebrae 3-8 about equal in width to one another and to sacral diapophyses; 18) intermandibularis and submentalis muscles connected; 19) supramandibular portion of interhyoideus forming simple tubular posterolateral extension; associated skin unmodified.
Osteocephalus leprieurii differs from all other members of the genus by having transverse dark bars on the back. Two other hylids (Hyla lanciformis and multifasciata) in the Amazon Basin have transverse dark marks on the dorsum. Both of these differ from leprieurii by having pointed snouts, much longer hind limbs, and smooth skin dorsally.
Distribution.—The periphery of the Amazon Basin, in the Guianas and the upper part of the basin in southern Colombia, Ecuador, Perú, and extreme western Brasil ([Fig. 9]). Most localities are at elevations of less than 500 m, but the species ascends the lower Andean slopes to elevations of 1100 m. 265 specimens from 31 localities.
Fig. 9. Distribution of Osteocephalus leprieurii (circles) and O. verrucigerus (triangles).
Remarks.—Most adults of leprieurii have distinct transverse markings on the back; these are variable in width, extent, and arrangement. In some specimens, such as USNM 166557, some of the transverse bars are fragmented into spots; in a few specimens the dorsal pattern consists solely of small dark spots arranged in transverse rows. Such specimens have a dorsal pattern resembling that of some taurinus. The transverse nature of the dorsal markings is further modified in some specimens, such as USNM 166555, in which the dark bars are fragmented and oblique.