Part 1

Produced by Chris Curnow, Tom Cosmas, Joseph Cooper and the Online Distributed Proofreading Team at http://www.pgdp.net

OCCASIONAL PAPERS

of the

MUSEUM OF NATURAL HISTORY The University of Kansas Lawrence, Kansas --------------------------------------------------------------- NUMBER 1 APRIL 29, 1971 ---------------------------------------------------------------

A SYNOPSIS OF NEOTROPICAL HYLID FROGS, GENUS OSTEOCEPHALUS

LINDA TRUEB AND WILLIAM E. DUELLMAN

Research Associate, Division of Herpetology, Museum of Natural History, University of Kansas.

Curator, Division of Herpetology, Museum of Natural History, University of Kansas.

When we initiated a study of the herpetofauna at Santa Cecilia in Amazonian Ecuador in 1966, we were immediately confronted with many kinds of animals that we could not identify with the existing literature. Comparisons of our specimens with those preserved in other museums resolved some of the problems, but many identifications could be made only after study of type specimens; even then some determinations remained questionable. We now find that in order to prepare a meaningful account of the herpetofauna of Santa Cecilia, we must complete several taxonomic studies, the limits of which extend far beyond eastern Ecuador. Because of our interests in hylids we have begun our studies on these frogs.

One of us (Trueb, 1970a) studied the cranial osteology of casque-headed hylid frogs and redefined the genus Osteocephalus but did not determine the number of species in the genus. Our work in Amazonian Ecuador resulted in the discovery of the sympatric occurrence of three species at each of two localities; one of these species was found with a fourth species at another locality. Study of museum specimens confirmed the recognition of these four species in the Amazon Basin and lower Amazonian slopes of the Andes. A fifth species from Bolivia and Peru also is included in the genus. Examination of museum specimens has provided data on the geographic variation in, and distribution of, the five species. However, our conclusions pertaining to some populations need substantiation, because we have been hampered by inadequate material from areas beyond Ecuador. More than half of the 905 specimens of Osteocephalus are from Ecuador, a relatively small part of the total range of the genus.

In this paper we are presenting a taxonomic review of the genus Osteocephalus; of necessity our study has been at the alpha level. We have utilized all of the usual external characters, as well as osteological features in our definitions of the species. Tadpoles and mating calls are available for only one species, O. verrucigerus (Trueb and Duellman, 1970); these and other important systematic characters, such as karyotypes, are not available for the group at this time. Our tendency has been to take a conservative view of species; thus it is doubtful that any subsequent worker will recognize fewer species in the genus. Our observations on these frogs in Amazonian Ecuador are presented in a final section of this paper.

ACKNOWLEDGMENTS

For the loan of specimens or for the provision of working space in their respective institutions, we are indebted to James E. Boehlke, Werner C. A. Bokermann, F. W. Braestrup, Nelly Carrillo de Espinoza, Osvaldo R. da Cunha, Josef Eiselt, M. J. Fouquette, Jr., Alice G. C. Grandison, Jean Guibe, Birgitta Hansson, Walter Hellmich, M. J. Hoogmoed, Robert F. Inger, Konrad Klemmer, Jean Lescure, Alan E. Leviton, Clarence J. McCoy, Robert H. Mount, Charles W. Myers, Umberto Parenti, Guenther Peters, James A. Peters, William F. Pyburn, Juan A. Rivero, Dorothy M. Smith, Paulo E. Vanzolini, Greta Vestergren, David B. Wake, Charles F. Walker, Ernest E. Williams, and Richard G. Zweifel.

Study of specimens in European museums was made possible by a grant (No. 5063) from the Penrose Fund of the American Philosophical Society. Field work in Ecuador was partially supported by grants from the Watkins Fund of the Museum of Natural History, University of Kansas. At our base camp at Santa Cecilia, Ecuador, we enjoyed the hospitality of Ing. Ildefonso Munoz B. Transportation in Ecuador was generously provided by the Texaco Petroleum Company. During the course of our field work Stephen R. Edwards and Thomas H. Fritts contributed directly to our study of Osteocephalus. Michael J. Tyler of the South Australian Museum provided information on the vocal sac structure. We extend our sincere thanks to all of these persons for their contributions to our endeavors.

MATERIALS AND METHODS

We have examined 893 preserved frogs, including the type specimens of all included nominal taxa, 8 skeletons, 1 lot of eggs, and 3 lots of tadpoles that we refer to the genus Osteocephalus; in addition skulls were removed from five preserved specimens, and radiographs were made of 12 other preserved specimens. We have been fortunate in seeing living individuals of all species, except O. pearsoni, but we have colored photographs of a living specimen of that species. Figures 1 and 2 were drawn from projected colored transparencies of living frogs. Terminology follows that of Duellman (1970b). On the distribution maps solid symbols indicate localities from which we have examined specimens; open symbols represent additional locality records based on the literature. Throughout the text specimens are listed by their catalogue numbers preceded by the appropriate museum abbreviation, as follows:

AMNH American Museum of Natural History ANSP Academy of Natural Sciences of Philadelphia ASU Arizona State University AUM Auburn University Museum BMNH British Museum (Natural History) CAS California Academy of Sciences CAS-SU Stanford University Collection (In California Academy of Sciences) CM Carnegie Museum FMNH Field Museum of Natural History KU University of Kansas Museum of Natural History MCZ Museum of Comparative Zoology, Harvard University MIZS Museo ed Istituto di Zoologi Sistematico, Universita di Torino MJP Museo Javier Prado, Lima MNHN Museum National d'Histoire Naturelle, Paris MPEG Museu Paraense Emiliano Goeldi, Belem MVZ Museum of Vertebrate Zoology, University of California, Berkeley MZUSP Museu de Zoologia, Universidade da Sao Paulo NHMG Naturhistoriska Museet Goeteborg NHMW Naturhistorisches Museum, Wien NHRM Naturhistoriska Riksmuseet, Stockholm RMNH Rijksmuseum van Natuurlijke Histoire, Leiden SMF Senckenbergische Museum, Frankfurt UIMNH University of Illinois, Museum of Natural History UMMZ University of Michigan Museum of Zoology UP Universite de Paris UPR-M University of Puerto Rico, Mayagueez UTA University of Texas, Arlington USNM United States National Museum UZM Universitets Zoologiske Museum, Copenhagen WCAB Werner C. A. Bokermann, Sao Paulo, Brasil ZMB Zoologisches Museum Berlin ZSM Zoologisches Sammlung Muenchen

HISTORICAL RESUME

Because of the taxonomic confusion that has surrounded the generic name Osteocephalus and two of the species (and their synonyms), we present a brief resume of the taxonomic history of the group.

Among the amphibians sent to the Museum National d'Histoire Naturelle in Paris by a Monsieur Leprieur in French Guiana was a single female specimen of a moderately large hylid having a well-ossified skull and smooth dorsal skin. This specimen escaped from the covetous eyes of Johann Tschudi, who prematurely named several species on the basis of specimens in Paris, and survived without an epithet until Dumeril and Bibron (1841) proposed for it the name Hyla leprieurii. The description of the species is fairly detailed, but the specimen was not illustrated. This is the earliest trivial name now associated with Osteocephalus.

Fitzinger (1843) in his generic synopsis of amphibians and reptiles proposed the generic name Osteocephalus but did not associate a specific name with the genus. Consequently, Osteocephalus Fitzinger, 1843, is a nomen nudum. Franz Steindachner followed Leopoldo Fitzinger at the Naturhistorisches Museum in Vienna, where he had access to Fitzinger's notes and, of course, the important collections housed in that museum. Steindachner (1862) named two species of Osteocephalus on the basis of Brasilian specimens collected by Johann Natterer. Both species were named in the same publication; O. taurinus appeared on page 77, and O. favolineatus, on p. 80. This is the earliest association of the generic name Osteocephalus with a specific name and a description, both of which satisfy the Code of Zoological Nomenclature for generic availability. Therefore, Steindachner is the authority for the generic name Osteocephalus, which has O. taurinus as the type species by original designation. It is not possible to determine whether or not Steindachner's usage of Osteocephalus was the same as that intended by Fitzinger 19 years earlier.

Steindachner (1862) gave reasonably good descriptions of his two new species and provided excellent illustrations of the two specimens, both large females. Apparently impressed by the similarities between Trachycephalus nigromaculatus Tschudi, 1838, and Osteocephalus taurinus, Steindachner (1867) used the combination Trachycephalus (Osteocephalus) taurinus. This ambiguous usage for the 1860's precludes our determining if Steindachner was in effect synonymizing Osteocephalus with Trachycephalus or whether he was placing Osteocephalus in a subgeneric status. Steindachner (1867) did not mention O. flavolineatus; perhaps by that time he had concluded that flavolineatus was only a color morph of taurinus.

Cope (1867) placed Hyla leprieurii in the genus Hypsiboas Wagler, 1830. Cope (1874) named Osteocephalus planiceps from Nauta, Peru. The single specimen was among the collections made by the Orton Expedition to the upper Amazon Basin and was deposited in the Academy of Natural Sciences in Philadelphia.

Boulenger (1882) placed both Osteocephalus and Trachycephalus the synonymy of Hyla; he recognized Hyla taurina (with O. flavolineatus as a synonym), H. leprieurii, and H. planiceps. In the same publication Boulenger named Hyla buckleyi on the basis of 10 specimens in the British Museum from Ecuador; in the description he stated that buckleyi was like leprieurii and taurinus in having paired lateral vocal sacs. Boulenger held a lasting influence on taxonomic herpetology, and his generic synonymy of Osteocephalus was unchallenged until only a decade ago.

Goin (1961) presented a generic synopsis of the genera of hylid frogs, in which he recognized Osteocephalus and stated: "There are perhaps eight or ten species of this genus in South America. Certainly taurinus, britti, leprieuri, buckleyi and pearsoni belong here. O. planiceps is surely a synonym of leprieuri and I believe that garbei is as well. The status of such forms as macrotis, riopastazae, and depressa has not yet been settled." Goin defined Osteocephalus as follows: "Males with paired vocal pouches, one at each angle of the jaw; derm of head not co-ossified with skull but roof of skull exostosed." Trueb (1970a) elaborated on Goin's definition and assuredly included only O. taurinus and O. leprieurii in the genus.

Goin's inclusion of buckleyi, britti, and pearsoni in Osteocephalus was the first association of any of these names with that genus. Duellman (1970a) demonstrated that Garbeana garbei Miranda-Ribeiro, 1926, was a member of the Hyla rubra group. Hyla macrotis Andersson, 1945, is a Phrynohyas. Trueb and Duellman (1970) determined that Hyla verrucigera Werner, 1901, is the earliest name for an Osteocephalus displaying striking sexual dimorphism in coloration and texture of the dorsal skin; Hyla riopastazae Andersson, 1945 (female holotype), and Hyla orcesi Funkhouser, 1956 (male holotype), were placed in the synonymy of Osteocephalus verrucigerus.

Hyla pearsoni Gaige, 1929, is a small species of Osteocephalus. Our findings substantiate Goin's suggestions relative to two other taxa. Hyla leprieurii britti Melin, 1941, from the Rio Uaupes, Brasil, and Hyla depressa Andersson, 1945, from the Rio Pastaza watershed, Ecuador, are members of the genus Osteocephalus, but both are synonyms of earlier names--leprieurii and taurinus, respectively. Another name proposed by Melin (1941), Hyla (Trachycephalus) vilarsi from Taracua, Brasil, also is placed in the synonymy of O. taurinus.

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.