Population Morphological Variation and Natural History ofAtractus potschi(Serpentes: Dipsadidae) in Northeastern Brazil

Abstract

Atractus potschi was described based on 12 specimens from the Brazilian states of Alagoas and Sergipe, and later knowledge of its morphological variation (meristic, morphometric, and color pattern data) was augmented on the basis of nine additional individuals from additional localities in northeastern Brazil. Based on the examination of collections and fieldwork, we found more than 70 additional specimens of Atractus potschi, 60 of them obtained during a single collecting event. In this paper, we report new data on intra-population morphological variation (external morphology, hemipenis, osteology, cephalic glands, and soft anatomy) and natural history for the species. We associate the variation displayed in some characters with sex or age. We relate most of the variation observed in the shape of the hemipenis with preparation artifacts at the moment of preserving specimens. Our results reveal a high level of population polychromatism, supplanting the geographical variability exhibited by this system, while other complexes of morphological characters are relatively conserved both within and among populations. Although this polychromatic pattern seems to be retained in several lineages of Atractus, this phenomenon might be related to distinct life history constrains of the species. On the basis of anecdoctal field data, we discuss the possibility of post-parturition aggregation of juveniles in Atractus potschi. Despite being based on a single observation, this report is significant, since such post-birth interactions in nature (other than reproductive ones) have only been documented previously in temperate regions.