Geographic variation in the morphology of the sand-dwelling lizard Nothobachia ablephara (Squamata: Gymnophthalmidae)

Abstract

Nothobachia ablephara is a small microteiid lizard with an elongated body and reduced limbs; it occurs in isolated dune fields in the state of Bahia (Xique-Xique and Alagoado) and small sandy patches in northeastern Brazil. A previous molecular study found a marked mtDNA divergence between populations of N. ablephara from Alagoado and Xique-Xique dunes, suggesting that the two populations diverged from one another between 3 and 4 million years ago. Given this isolation, it is interesting to explore whether morphological traits of the lizards reflect the reported genetic divergence of the populations. Scale counts of the sexes and the populations differ significantly, but there is considerable overlap of values. Univariate and multivariate analyses revealed significant morphometric variation between sexes and populations; however, this is mostly explained by size differences. Females are larger than males in all characters that are sexually dimorphic, and individuals from Xique-Xique are larger than those from Alagoado in all characters that vary geographically. The sample from Alagoado has more sexually dimorphic characters than the one from Xique-Xique. Although N. ablephara displays some geographical variation, the two populations could not be unequivocally distinguished by scale counts and morphometric data.