A new genus of microteiid lizard from the Atlantic forests of State of Bahia, Brazil, with a new generic name for Colobosaura mentalis, and a discussion of relationships among the Heterodactylini (Squamata, Gymnophthalmidae) ; American Museum novitates, no. 3565

A new genus and species of microteiid lizard is described from a series of specimens obtained in the leaf litter at Una (15°10′S, 39°03′W) in the Atlantic forest of southern Bahia, Brazil. It is characterized by the presence of prefrontals, frontoparietals, parietals, and interparietal; parietals longer than wide; distinct ear openings and eyelids; two pairs of genials, absence of collar and occipital scales; dorsal scales anteriorly smooth and becoming gradually lanceolate and mucronate posterior to the forelimb; and four regular transverse series of smooth ventrals that are longer than wide, identical in size. A phylogenetic analysis based on external morphology, osteology, and molecular data confirms this new lizard as a member of the Heterodactylini radiation of Gymnophthalminae. The topology recovered by maximum parsimony (MP) analyses reveals that its closest relatives are the sister taxa Colobosaura modesta and Iphisa elegans (BS = < 50%; Bremer value = 2) and the partitioned Bremer indexes indicated that the largest contribution to this relationship comes from morphology; Colobosaura mentalis, for which a new generic name is here proposed, is basal to this radiation. Our analyses confirm a previous hypothesis suggesting Stenolepis as a member of the Heterodactylini radiation and that the clade composed of Colobodactylus and Heterodactylus is the sister group of the clade formed by Colobosaura mentalis-Stenolepis (BS = 100; Bremer value = 18), Colobosaura modesta-Iphisa (BS = < 50%; Bremer value = 1), and the new genus here described. The support for Heterodactylini monophyly, on the basis of combined MP analyses is higher (BS = 96, Bremer value = 11) than that previously found in molecular-based studies only. Partitioned Bayesian methodology combining molecular and morphological data sets recovered the new genus as the sister taxon (PP = 0.94) of the clade (PP = 0.94) formed by I. elegans-C. modesta (PP = 0.51) and C. mentalis-S. ridleyℝ (PP = 1.0). An alternative topology demonstrating a paraphyletic Heterodactylini is only weakly supported (PP = 0.63). Based on the MP topology we discuss tentative scenarios for the evolution of Heterodactylini.
27 p. : ill. ; 26 cm.
Includes bibliographical references (p. 20-21).