A new species of the Pantepui endemic genus Riolama (Squamata: Gymnophthalmidae) from the summit of Murisipán-tepui, with the erection of a new gymnophthalmid subfamily

Abstract

The gymnophthalmid lizard Riolama inopinatasp.nov. is described from the summit of Murisipán-tepui, Bolívar State, Venezuela. The new species is characterized by its small size, slender body, short neck, chestnut brown dorsum with two conspicuous orange-brown dorsolateral stripes, 30 or 31 mid-dorsal scales, and 18 or 19 ventral scales in transverse rows, 28 scales around midbody, seven supralabials, five or six infralabials, subdigital lamellae divided in small granular scales, ten or 11 small femoral pores in males, dorsal surface of tongue covered with oblique chevron-shaped plicae interrupted by a small midsection of imbricate scale-like papillae, and a small weakly bilobed hemipenis having the sulcus spermaticus flanked by an extensive nude area on each side, and the asulcate and lateral faces of the organ with short series of small roughly equidistant, feebly developed flounces, each bearing a single medial hook-shaped spine. Molecular phylogenetic analyses based on one nuclear and two mitochondrial DNA genes confirm the allocation of the new species to the genus Riolama, but do not support the assignation of Riolama to the subfamily Cercosaurinae as previously suggested based on overall morphological similarities, nor to any other known subfamily of the Gymnophthalmidae. Therefore, a new subfamily, the Riolaminae, is proposed to accommodate the genus.