Part 2

_Skin._--The dorsal skin of all males of _Osteocephalus_ is tuberculate to varying degrees, whereas the dorsal skin of females is smooth, or nearly so (Fig. 4). _Osteocephalus verrucigerus_ differs from other members of the genus by the presence of numerous, large tubercles bearing keratinized tips. The tubercles of _leprieurii_ are numerous and spinous but much smaller than those of _verrucigerus_; those of _taurinus_ are spinous but less numerous than in _leprieurii_. _Osteocephalus buckleyi_ has a mixture of large and small, non-spinous tubercles, and _pearsoni_ has only a few, small, scattered, non-spinous tubercles. Fleshy tubercles occur on the eyelids and supratympanic fold in females of _buckleyi_; a few small tubercles are present on the back of females of _pearsoni_, whereas the dorsal skin in females of the other species is smooth. The skin on the flanks of both sexes of _buckleyi_ is weakly areolate; in the other species the flanks are smooth. The skin on the top of the head in _taurinus_ is rugose as a consequence of co-ossification. In all species the anal opening is directed posteriorly at the upper level of the thighs.

_Hands and Feet._--The feet of _Osteocephalus_ are fully webbed or nearly so. Webbing between fingers one and two is basal in all species. Webbing between fingers two, three, and four is most extensive in _taurinus_, in which the three fingers are about one-half webbed (Fig. 5). _Osteocephalus buckleyi_, _pearsoni_, and _verrucigerus_ have reduced webbing between fingers two and three, and _leprieurii_ has reduced webbing between fingers two, three, and four. All members of the genus have well-developed subconical subarticular tubercles on the fingers and toes; there is a tendency for the distal tubercle on the fourth finger to be weakly bifid. Palmar and plantar supernumerary tubercles are well developed in _taurinus_, moderately developed in _buckleyi_, _leprieurii_, and _pearsoni_, and barely evident in _verrucigerus_. All of the species have a noticeable fold on the wrist and enlarged prepollices, bearing horny nuptial excrescences in breeding males. The prepollex is least enlarged in _buckleyi_. Outer metatarsal tubercles are absent. The inner metatarsal tubercle is moderately well developed and ovoid in _leprieurii_ and _pearsoni_; it is elliptical and flat in the other species. Tarsal folds are absent in all species except _verrucigerus_, in which the folds are barely evident.

_Cranium._--As a genus, the cranial structure is remarkably uniform and quite generalized when viewed in the context of the family Hylidae. The skulls are broad and relatively flat, each being only slightly more broad than long and about one-third as high as long. In dorsal aspect the snouts are broadly rounded; the snout of _buckleyi_ is somewhat less rounded and appears to be slightly longer than the snouts of other species. This subtle difference relates to the relative narrowness of the premaxillaries in _buckleyi_.

The genus is characterized by well-developed dermal roofing bones and an unusually large exposure of the sphenethmoid dorsally (Fig. 6). The conformation of the sphenethmoid exposed dorsally is determined by the marginal positions of the adjacent, overlapping elements--the nasals and frontoparietals. Medially the nasals overlap the lateral margins of the sphenethmoid. Anteromedially, the nasals converge in _leprieurii_ and _taurinus_, are narrowly separated in _buckleyi_ and _pearsoni_, or are more widely separated in _verrucigerus_. In all species the nasals terminate at the anterodorsal corner of the orbit. The frontoparietals of _buckleyi_, _leprieurii_, and _taurinus_ have an anterolateral extension, which marginally overlaps the dorsolateral edge of the sphenethmoid and articulates with the posterodorsal corner of the nasal in _buckleyi_ and _taurinus_; the bones are narrowly separated in _leprieurii_. The frontoparietals of _pearsoni_ and _verrucigerus_ have more extensive median ossification and less extensive anterolateral ossification. Thus, in those species the posteromedian portion of the sphenethmoid is obscured, and the lateral margins are partly exposed. The frontoparietal fontanelle is completely covered in all species, except _buckleyi_ and _leprieurii_, in which an irregular, median separation of the frontoparietals exposes a small portion of the fontanelle. The posterolateral margins of the frontoparietals lie medial to the epiotic eminences.

Dermal ornamentation, involving the nasals, frontoparietals, and sphenethmoid, occurs in _taurinus_ and, to a limited extent, in _pearsoni_. In the latter species marginal portions of the frontoparietals, the dorsal surfaces of the nasals, and the posteromedial part of the exposed sphenethmoid are slightly exostosed, resulting in an open, reticulate pattern of dermal sculpturing of exceedingly low relief (Fig. 6c). _Osteocephalus taurinus_ is characterized by casquing, co-ossification, and a rather intricate pattern of dermal sculpturing, which was described in detail and illustrated by Trueb (1970a).

The squamosals of all species are moderately large structures having otic plates that overlie the lateral portion of the cristae paroticae. The posterior rami are short; the zygomatic rami of all species, except _taurinus_, extend slightly more than one-half of the distance to the maxillary. In _taurinus_ the zygomatic ramus extends nearly to, or articulates with, the maxillary.

The maxillary arches are complete and relatively robust. The alary processes of the premaxillaries are vertically oriented in _leprieurii_, _pearsoni_, and _taurinus_ and very slightly inclined posteriorly in _buckleyi_ and _verrucigerus_. The maxillaries are uniformly characterized by the absence of postorbital processes and by the presence of preorbital processes that articulate with the maxillary processes of the nasals. The partes facialae of the maxillaries are moderately developed in all species, except _taurinus_, in which the pars fascialis tends to articulate with the lateral margin of the nasal in well-ossified individuals. The partes palatinae are poorly developed in all species, except _buckleyi_, in which the pars palatina of the premaxillary is moderately robust.

The pterygoids are uniformly tri-radiate structures. The anterior rami terminate at about the mid-level of the orbit, and the medial rami articulate firmly with the anterolateral corner of the otic capsule. The palatines are well-developed elements bearing ventral ridges; the ridges are somewhat irregular in _buckleyi_, _taurinus_, and _verrucigerus_ but smooth in _leprieurii_ and _pearsoni_. The parasphenoids are large elements characterized by acuminate cultriform processes and posterolaterally inclined alary processes. The basal areas of the cultriform processes bear small odontoid protuberances in _buckleyi_, _taurinus_, and _verrucigerus_, whereas they are smooth in _leprieurii_ and _pearsoni_. The prevomers are remarkably uniform, moderately well-developed structures. In each species the anterior ramus lies adjacent to the premaxillary, and the lateral wings form the anterior, medial, and posteromedial margins of the internal nares. The dentigerous processes are characteristically large and angular and bear numerous teeth. The sphenethmoid and otoccipitals are well ossified; a dermal sphenethmoid is present only in _taurinus_.

_Vertebral Column._--The cervical cotyles are uniformly widely displaced. The neural arches are low and non-imbricate. The transverse processes of the third presacral vertebrae are approximately equal in width to the sacral diapophyses in all species, except _buckleyi_, in which the processes of the third presacral are slightly narrower than the diapophyses. _Osteocephalus buckleyi_ is further distinguished by the presence of narrow transverse processes on presacrals five through eight (Fig. 7b); males have narrower processes than do females. The processes are moderately wide but subequal in width in _pearsoni_, _taurinus_, and _verrucigerus_, whereas they are nearly equivalent in width to one another and to the sacral diapophyses in _leprieurii_ (Fig. 7a). The sacral diapophyses of all species are moderately dilated and posterolaterally inclined. The coccyx bears a distinct dorsal ridge and has a bicondylar articulation with the sacrum.

_Pectoral Girdle._--The pectoral girdles are fully arciferal and bear small, cartilaginous omosterna and moderately large cartilaginous sterna. The coracoids are robust, and the clavicles are strongly arched. Procoracoid cartilage seems to be absent. The scapulae are large, longer than the clavicles, and bicapitate proximally. The suprascapulae are moderately large and well ossified in _leprieurii_ and _taurinus_. The suprascapula of _verrucigerus_ is poorly ossified, and that of _buckleyi_ is not ossified.

_Pelvic Girdle._--The ilia of _buckleyi_, _taurinus_, and _verrucigerus_ lack any indication of a crest on the shaft, whereas _leprieurii_ has a low crest. The dorsal acetabular expansion of the ilia is moderately low in _taurinus_ and _verrucigerus_, but distinctly lower in _buckleyi_ and _leprieurii_. The ilia of all species bear low dorsal protuberances. The ischia of _leprieurii_, _taurinus_, and _verrucigerus_ are moderately expanded; that of _buckleyi_ is somewhat less expanded dorsally. The pubis of _leprieurii_, _taurinus_, and _verrucigerus_ are calcified, whereas that of _buckleyi_ remains cartilaginous.

_Throat Musculature and Vocal Sac Structure._--Tyler (1971) described the throat myology of _Osteocephalus_. The genus is characterized by a moderate-sized araphic submentalis muscle and an undifferentiated intermandibularis having an elongate median aponeurosis. The intermandibularis and submentalis are completely independent in _buckleyi_, whereas in the other species there is a small attachment between these muscles.

According to Tyler (pers. com.), _Osteocephalus_ has three distinctive types of vocal sac structure which result from differences in the development of the interhyoideus muscle and the overlying skin. In _leprieurii_ and _verrucigerus_ the supramandibular portions of the interhyoideus form a simple tubular, posterolateral extension; there is no modification of the associated skin. _Osteocephalus buckleyi_ and _pearsoni_ have more extensive development of the supramandibular portions of the interhyoideus; furthermore, the associated skin forms a broad, loose fold extending from the ventromedial surface of the throat dorsolaterally to the base of the supratympanic fold. Like _buckleyi_ and _pearsoni_, the supramandibular portion of the interhyoideus is much expanded in _taurinus_. The vocal sac structure of _taurinus_ differs from that of other members of the genus in that the skin of _taurinus_ forms an everted pouch, which dangles loosely beneath the supratympanic fold.

KEY TO THE SPECIES OF _Osteocephalus_

1. Inner edge of third finger webbed to mid-length of antepenultimate phalange; dorsum brown with dark brown spots or median blotch; skull in adults casqued and co-ossified with prominent supraorbital flanges _O. taurinus_

Inner edge of third finger webbed to base of antepenultimate phalange; dorsum plain or marked with dark blotches or transverse bars; skull in adults smooth or slightly exostosed, lacking supraorbital flanges 2

2. Skin on flanks areolate; dorsum in males bearing a mixture of large and small non-spinous tubercles; lips distinctly barred _O. buckleyi_

Skin on flanks smooth; dorsum in males bearing tubercles of uniform size; lips not barred 3

3. Dorsal pattern consisting of narrow transverse dark bars; dorsum in males bearing numerous small spinous tubercles _O. leprieurii_

Dorsal pattern not consisting of transverse bars; dorsal tubercles large or few in number 4

4. Dorsum uniformly dark brown; venter heavily mottled with black, especially in females; dorsum in males bearing large, keratinized tubercles _O. verrucigerus_

Dorsum tan with irregular dark brown blotches; venter cream with fine brown reticulations; dorsum in males bearing few, small non-spinous tubercles _O. pearsoni_

ACCOUNTS OF SPECIES

=Osteocephalus buckleyi= (Boulenger)

_Hyla buckleyi_ Boulenger, 1882:362 [Syntypes.--BMNH 1947.2.13.36-39 from Sarayacu, Provincia Pastaza, Ecuador; BMNH 1947.2.13.40-41, 1947.2.13. 43-45 from Canelos, Provincia Pastaza, Ecuador; BMNH 1947.2.13.46 from "Paitanga" (= Pallatanga), Provincia Chimborazo, Ecuador (in error); Mr. Buckley collector; BMNH 1947.2.13.44 here designated as lectotype].

_Hyla festae_ Peracca, 1904:39 [Holotype.--MIZS 2950 from "Valle de Santiago" (= lower Río Zamora), Provincia Morona-Santiago, Ecuador; Enrico Festa collector]. New synonymy.

_Osteocephalus buckleyi_--Goin, 1961:13.

_Hyla carri_ Cochran and Goin, 1970:211 [Holotype.--FMNH 69702 from Acevedo, Río Suaza, Departamento Huila, Colombia; Philip collector]. New synonymy.

_Hyla cabrerai_ Cochran and Goin, 1970:215 [Holotype.--USNM 152759 from Caño Guacayá, tributary of lower Río Apoporis, Comisaria Amazonas, Colombia; Isadore Cabrera collector]. New synonymy.

_Justification of Synonymy._--Boulenger (1882:362) listed 11 specimens in his description of _Hyla buckleyi_. We have examined all of these and conclude that one (BMNH 1947.2.13.42) is _O. leprieurii_. Cochran and Goin (1970:213) restricted the type locality to Canelos, Provincia Pastaza, Ecuador; we here select BMNH 1947.2.13.44 from that locality as the lectotype. This specimen is a male having a snout-vent length of 37.9 mm; the diameter of the tympanum is 3.5 mm, 81.4 percent of the diameter of the eye. The type series, exclusive of BMNH 1947.2.13.42 (=_O. leprieurii_) consists of six males having snout-vent lengths of 37.9-44.6 (mean 40.4) mm, and four females having snout-vent lengths of 50.0-53.9 (mean 51.5) mm. The dorsum in the males bears a mixture of large and small tubercles, whereas the dorsum in females is nearly smooth. The skin on the flanks, especially the axilla, is areolate. The coloration consists of a creamy tan ground color with irregular reddish brown markings on the back and broad transverse bars on the limbs. The dorsal markings are narrowly bordered by creamy white; those on the back consist of an interorbital bar and a pair of longitudinal marks beginning in the scapular region and usually diverging posteriorly in the sacral region or converging into a broad median blotch. One specimen has a middorsal creamy white stripe from the tip of the snout to the vent. In all of the types large dark brown spots are present on the flanks and posterior surfaces of the thighs. The ventral surfaces are pale creamy tan with or without diffuse brown spots on the throat and chest.

The holotype of _Hyla festae_ is a female having a snout-vent length of 75.0 mm; the diameter of the tympanum is 3.9 mm, 57.4 percent of the diameter of the eye. The skin is smooth on the dorsum and areolate on the anterior part of the flanks. The dorsum is pale brown with a large median longitudinal dark brown blotch on the back and broad transverse bars, narrowly outlined by cream, on the limbs. Dark brown spots are present on the flanks; the posterior surfaces of the thighs are dark brown. The throat and belly are grayish white with irregular dark brown spots.

The holotype of _Hyla carri_ is a female having a snout-vent length of 66.1 mm; the diameter of the tympanum is 4.7 mm, 81.0 percent of the diameter of the eye. The skin on the dorsum is smooth with scattered small tubercles and areolate on the anterior part of the flanks. The dorsum is tan with irregular dark brown blotches on the back and transverse bars on the limbs; all dorsal markings are narrowly outlined by creamy white. Dark brown spots are present on the flanks; the venter and posterior surfaces of the thighs are tan without dark spots.

The holotype of _Hyla cabrerai_ is a female having a snout-vent length of 52.7 mm; the diameter of the tympanum is 4.0 mm, 76.9 percent of the diameter of the eye. The skin on the dorsum is weakly tuberculate and that on the anterior part of the flanks is areolate. The dorsum is creamy tan with dark brown markings (interorbital bar, reticulations on occiput, three longitudinal streaks on back, and broad transverse bars on limbs). Irregular dark brown spots are present on the flanks. The venter is pinkish tan with small reddish brown spots on the throat and darker brown spots on the chest and belly.

In their description of _Hyla cabrerai_, Cochran and Goin (1970:217) stated: "This species, together with _buckleyi_ and _pearsoni_ certainly make a closely knit group.... Both _buckleyi_ and _cabrerai_ have long hind legs, with the extended heel reaching to the tip of the snout, while in _pearsoni_ the extended heel reaches only to the eye. _H. buckleyi_ has the belly dusky, while it is heavily spotted in _cabrerai_ and is reticulated in _pearsoni_. _H. cabrerai_ seems to have the heaviest hands with the most webbing between the fingers; the other two species have the webbing reduced between the fingers." The description of _Hyla cabrerai_ was based on three specimens. We have examined the holotype and one paratype (WCAB 13284 from Territorio do Amapá, Brasil). Another paratype in the private collection of C. J. Goin from Caño Tuí, between Mitú and Raudal de Yurupari, Comisaria de Vaupés, Colombia, was not examined.

Cochran and Goin (1970:211) based their description of _Hyla carri_ on one gravid female and stated: "A large _Hyla_ with the vomerine teeth in two ^^ shaped patches between the somewhat squarish choanae; reduced webs between the fingers; and a pattern of dorsal dark blotches bordered by light margins. The species is not similar to any other species known in Colombia. It is perhaps most closely related to _Hyla claresignata_ of Brazil, from which it can be differentiated by its more heavily spotted dorsum, larger tympanum, and lack of dark anal spots."

Except for the inclusion of the name in checklists, _Hyla festae_ has not been mentioned in the literature since the original description.

The wholesale synonymization of names, which, on the bases of their published diagnoses, seem to apply to distinctly different species, is possible with the application of uniform criteria to the types and series of other specimens. In measurements and proportions the type specimens of the nominal taxa all fall within the range of variation exhibited by a series of 18 males and 15 females from Provincia Pastaza, Ecuador, except the ratio of the diameter of the tympanum to that of the eye in the female holotype of _Hyla festae_. In that specimen the ratio is 0.574, whereas the ratio in the 15 females from Provincia Pastaza is 0.587-0.905 (mean 0.736).

Ventral coloration is the most variable character among the types. The venter in the type of _Hyla festae_ is boldly spotted; it is distinctly spotted in _cabrerai_, uniform tan in _carri_, and tan, flecked, or spotted in the type series of _buckleyi_. The ventral coloration in series of specimens from Amazonian Ecuador encompasses that observed in all of the types, except that of _festae_, which has more ventral spotting than any other individual.

The webbing on the hand usually excludes the penultimate phalanges of the fingers, but in some specimens from Amazonian Ecuador the webbing encompasses the proximal parts of the penultimate phalanges of the fingers. In a few of these specimens, the holotype of _festae_, and one paratype of _cabrerai_ the webbing extends to the middle of the penultimate phalanges of the third and fourth fingers. In the holotype of _cabrerai_ the webbing extends to the middle of the penultimate phalanges of the third and fourth fingers and to the base of the disc of the second finger.

The types of the nominal taxa and series of specimens from Guyana and Amazonian Ecuador display noticeable variation in dorsal coloration. The variety of dorsal patterns of all of the types is included in the variation displayed by the other specimens. All specimens have some amount of dark spotting on the flanks; all have vertically barred lips, on which a pale subocular spot usually is evident. Probably the most unifying physical characteristic of all of the specimens is the nature of the skin on the anterior part of the flank. The skin is elevated amidst an irregular network of depressions. This areolate dermal condition is present in all specimens and does not occur in other species of _Osteocephalus_. The degree of tubercularity of the skin on the dorsum is variable and sexually dimorphic. All males are tubercular, whereas small females are smooth or have only a few scattered tubercles. Large females usually have pronounced tubercles on the eyelids and supratympanic fold.

In their description of _Hyla carri_, Cochran and Goin (1970:211) misrepresented the nature of the dentigerous processes of the prevomers, which are angular, not ^-shaped. Their suggestion that the Colombian _Hyla carri_ is related to _Hyla claresignata_ in southeastern Brasil is unfounded. The latter species is smaller (40 mm), has a yellow dorsum and venter, dark brown spots dorsolaterally, oblique dentigerous processes of the prevomers, small tympanum, and smooth skin dorsally.

The ventral coloration of the type of _Hyla festae_ resembles that of _Osteocephalus verrucigerus_, but the type differs from _verrucigerus_ by having areolate skin on the flanks and distinct dark markings on the dorsum. In _verrucigerus_ the skin on the flanks is smooth, and the dorsum is uniform dark brown, except for a tan snout in females.

Comparisons of the types of the nominal species with series of specimens from Guyana, Colombia, Ecuador, and Perú suggest strongly that the types are representative of one taxon, the oldest name for which is _Hyla buckleyi_ Boulenger, 1882. Consequently, we place _Hyla festae_ Peracca, 1904, _Hyla carri_ Cochran and Goin, 1970, and _Hyla cabrerai_ Cochran and Goin, 1970, as junior synonyms of _Hyla buckleyi_ Boulenger, 1882.