Gilson Rivas Fuenmayor

An Enigmatic New Snake from Cloud Forest of the Península de Paria, Venezuela (Colubridae: Genus Taeniophallus?)

Abstract The snake Taeniophallus nebularis, new species, is known from a single specimen collected in montane cloud forest, 800 m above sea level, Península de Paria, northeastern Venezuela. It is a small “xenodontine” colubrid (adult male, 492 mm total length); dorsal scales in 19-19-17 rows, smooth, with paired apical pits anteriorly; brown dorsally and grayish laterally, with ill-defined pattern; white postocular stripe; and bright yellow midventrally between serrated black edges. The species is easily diagnosed, although assignment to Taeniophallus is problematic. However, a few suggestive characters are shared with T. brevirostris and T. nicagus. These species, presumably the closest geographic relatives of T. nebularis, occur in the Amazon basin and the Guianas, indicative of a biogeographic parallel with certain plants. Taeniophallus occipitalis, with extreme scale-row reduction and a distinctive color pattern possibly derived from a brevirostris-like precursor, is widely distributed south of the Amazon. Four additional species of Taeniophallus s.l. comprise the monophyletic affinis species group centered in southeastern Brazil. The genus Echinanthera (also centered in southeastern Brazil) is sometimes expanded to include all of Taeniophallus. Echinanthera s.s. is viewed as a demonstrably monophyletic group of six named species, whereas relationships of the subgroups of Taeniophallus s.l. among themselves and to Echinanthera remain uncertain. Evolutionary divergence in copulatory organs of the otherwise similar Taeniophallus nicagus and T. brevirostris is extraordinary, suggesting that uncritical weight cannot safely be assigned to hemipenial characters of presumptive relatives. The hemipenis of Taeniophallus nebularis differs from those of other taxa discussed in being conspicuously bilobed for nearly a third of its length. However, some degree of bilobation is symplesiomorphic for these snakes, as evidenced by presence or absence of weak bilobation in a few species and divided insertions of retractor muscles in all. The penial asulcate interspinal gap in T. nebularis also might be symplesiomorphic for Taeniophallus s.l. and Echinanthera s.s., but homologies and level of generality for this character are not yet clear.

New Species of Lizards from Auyantepui and La Escalera in the Venezuelan Guayana, with Notes on “Microteiid” Hemipenes (Squamata: Gymnophthalmidae)

Abstract Names are provided for two montane gymnophthalmid lizards that have been long known from the Venezuelan Guayana, but that were not described by other workers because specimens had been lost. Euspondylus auyanensis, new species ( =  Anadia sp. auctorum), is known only from the summit of Auyantepui, where it was originally discovered by S. Gorzula in 1984; a later specimen, the holotype, was collected by Renaud Boistel in 1998. The monophyly of Euspondylus has not been established and the generic assignment is tentative. Anadia escalerae, new species, is based on a specimen obtained by John Cadle in 1980, in the region of La Escalera, to the east of Auyantepui. It agrees with Anadia sensu stricto in being a slender attenuate lizard, but is unusual in having weakly keeled (vs. smooth) dorsal scales and in having the prefrontals separated by an azygous scale. The last condition also occurs in the holotype of A. pariaensis from the Península de Paria, about 500 km NNW of La Escalera; although differing in several characters, they may be sister species. A new specimen of the rare Anadia blakei (from Cerro Humo, Península de Paria), is described and illustrated. It is a robust lizard, markedly different in habitus from Anadia sensu stricto. Commentary is provided on the usefulness of hemipenial data in gymnophthalmid systematics. The hemipenes of Euspondylus auyanensis, Anadia blakei, and A. ocellata are described and illustrated. The Guayana endemic genus Adercosaurus is provisionally assigned to the subfamily Alopoglossinae based on hemipenial and other resemblances to Ptychoglossus.

A NEW AQUATIC SNAKE (COLUBRIDAE: PSEUDOERYX) FROM THE LAKE MARACAIBO BASIN, NORTHWESTERN VENEZUELA: A RELIC OF THE PAST COURSE OF THE ORINOCO RIVER

A new species of aquatic snake in the genus Pseudoeryx is described from the Lake Maracaibo Basin in northwestern Venezuela. The new species differs from P. plicatilis, the only other species in the genus, by having a nuchal band, a distinctive ventral coloration, the relative size of the genial plates and having different maxillary dentition. This discovery further supports paleogeographic reconstructions of the course of a proto-Orinoco/Amazon river.