B R E V I O R A LIBRARY usenm of Comparative Zoology ^ APR 3 1996 us ISSN 0006-9698 Cambridge, Mass. 18 April 1996 :'_^' Number 504 i Vi:LF^...Jl j 1 THE GENUS PHENACOSAURUS (SQUAMATA: IGUANIA) IN WESTERN VENEZUELA: PHENACOSAURUS TETARII, NEW SPECIES, PHENACOSAURUS EUSKALERRIARI, NEW SPECIES, AND PHENACOSAURUS NICEFORI DUNN, 1944 Tito R. Barros,' Ernest E. Williams,-and Angel Viloria' Abstract. Two new, possibly parapatric species of Phenacosaurus are de-scribed from the Sierra de Perija, Estado Zulia, Venezuela: P. tetarii, larger, at least 85 mm snout-vent length, with heterogeneous squamation on the flanks, closest to P. nicefori but larger in adult size, and P. euskalerriari, small, about 56 mm snout-vent length, with uniform flank squamation, closest to P. orcesi, but with larger flank scales and shorter interparietal. Phenacosaurus nicefori Dunn is redescribed on the basis of material from Be-tania, Estado Tachira, Venezuela, and from the Paramo de Tamo, overlapping the borders of both Colombia and Venezuela, as well as from topotypic material from Norte de Santander in Colombia. INTRODUCTION The members of the genus Phenacosaurus are anoline lizards endemic to the subparamo and paramo of northwestern South America and are characterized by a casqued head with converging lateral parietal crests with a smaller or larger notch at their oc-cipital ends, a variable vertebral crest, short limbs, and a probably prehensile tail. Initially they were believed to be present only in Colombia, from where the type species, Phenacosaurus heteroder-mus, was described by Dumeril and Dumeril in 1851. Dunn (1944), studying material in Colombian collections, added two new species to the genus, P. nicefori from the Department of Norte de Santander and P. richteri from the Department of Cundina-' Museo de Biologia, Facultad de Ciencias, Universidad del Zulia, Apartado 526, Maracaibo 4033, Zulia, Venezuela. ^ Museum of Comparative Zoology, Harvard University, Cambridge, Massachu-setts 02138.