CHARACTERIZATION OF AMPHISBENIUM Leposternon polystegum (DUMÉRIL in DUMÉRIL & DUMERIL, 1851) (SQUAMATA, AMPHISBAENIA) AND COMPARISON WITH RELATED SPECIES
Amphisbaenians; taxonomy; Amazon; clinal variation, geographic distribution.
Leposternon polystegum forms one of the eleven species of the genus Leposternon, which has been shown to possess high morphological variability in some valid species, as well as contain possible new taxa. The diagnoses and characterizations of most species were based on external morphology, but not all species have well-defined diagnostic characters or an analysis of morphological variation. Consequently, in the current study, specimens of L. polystegum from scientific collections were analyzed to provide such morphological data, and so aid in the diagnosis of the species and further the understanding of its geographic distribution. Additionally, measurements from L. polystegum were compared with phylogenetically related congeners with pre-cloacal pores. Eleven meristic and 39 morphometric characters were analyzed, using descriptive and multivariate statistical analyses. The results of the current study were structured into two chapters. In the first, L. polystegum is characterized morphologically with new meristic and morphometric data, a diagnosis provided and the intraspecific variation
tested and identified as a possible clinal variation. Additionally, the geographic distribution of L. polystegum was analysed and structured in a gazetteer and an updated map. In the second article, L. mineiro, a species with pre-cloacal pores, was re-characterized with new morphological data and its geographic distribution was expanded.