Análise da variação morfológica em Bothrops moojeni e espécies associadas

Abstract

The genus Bothrops comprises a group of venomous snakes widely distributed throughout the Neotropics and presents a complex pattern of morphological variation. Among Bothrops species, the atrox group is composed by: B. atrox Linnaeu, 1758; B. leucurus Wagler, 1824; B. moojeni Hoge, 1966; B. marajoensis Hoge, 1966; B. asper Garman, 1883; B. isabelae Sandner Montilla, 1979; B. colombienses Hallowell; B. caribbaeus Garman, 1887 and B. lanceolatus Bonnaterre, 1790. The difficulty of morphological characterization of the species of this group has stimulated several discussions among researchers about the taxonomic validity of some representatives and their real geographic limits. This paper brings a taxonomic revision of the species of B. moojeni through the use of morphological evidence. Populations of B. atrox and B. leucurus historically associated with B. moojeni were also analyzed. Morphometric, meristic characters and drawing and coloration patterns of 362 specimens were analyzed, and statistical analyses were performed among the species. The study was conducted at the Laboratory of Zoological Collections of the Instituto Butantan. The described characteristics of the studied species showed similarities, demonstrating the recurring difficulty in identifying them. Furthermore, overlapping populations were recorded in the Cerrado region between B. atrox and B. moojeni, and the latter with B. leucurus in areas near the Atlantic Forest. A Principal Component Analysis (PCA) was used to show sexual dimorphism among species, and Boxplot, Plot and Histogram charts were used to observe the analyses. The morphological and meristic analyses of B. moojeni, B. atrox and B. leucurus in this study showed significant dimorphism in twelve of the 32 variables analyzed. We observed significant differences in B. atrox in the amount of ventral and sub-caudal scales, as well as in head width. The combination of these results demonstrates that the diversity of the atrox group is complex and its characters overlap across the three species, making morphological relationships among them similar. However, to better understand the differentiation between the species analyzed further research through phylogenetic and molecular analyses and to analyze more specimens will be necessary.