Variação morfológica e distribuição geográfica de Placosoma glabellum (Peters, 1870) (Squamata: Gymnophthalmidae: Cercosaurini)

Abstract

Placosoma glabellum (Peters, 1870) is a lizard of the family Gymnophthalmidae Fitzinger, 1826, endemic to the Brazilian Atlantic Forest, whose distribution and morphological variation remain poorly explored. The present study aimed to review the external morphology and geographic distribution of the species through the examination of 22 specimens from scientific collections, in which meristic and morphometric characters were evaluated, in addition to the compilation and spatial analysis of 185 occurrence records obtained from zoological collections, specialized literature, and online databases. The results showed that P. glabellum exhibits greater morphological variation than previously recognized, including differences in the ranges of meristic characters and sexual dimorphism in femoral pores, in the relative width of the tail base, and in the conformation of the preanal scales, as well as pronounced variation in pore occurrence among females. The geographic analysis confirmed the species' association with the remnants of Atlantic Forest in southern and southeastern Brazil and revealed disparities in sampling effort across its known distribution. Additionally, the first confirmed record for the Jequitinhonha Valley, in northeastern Minas Gerais, was documented, extending the known northern limit of the species by approximately 400 km. The results obtained expand the current knowledge of the morphology and distribution of P. glabellum,providing relevant findings for taxonomic, biogeographic, and conservation studies.