Based on comprehensive distributional records of the 23 species currently assigned to the lizard genus Tropidurus, we investigated patterns of endemism and area relationships in South America. Two biogeographic methods were applied, Parsimony Analysis of Endemicity (PAE) and Brooks Parsimony Analysis (BPA). Two areas of endemism were detected by PAE: the first within the domains of the semiarid Brazilian Caatinga, which includes seven endemic species, and the second in the region of the Serranía de Huanchaca, eastern Bolivia, in which three endemic species are present. The area cladograms recovered a close relationship between the Atlantic Forest and areas of the South American open corridor. The results revealed a close relationship among the provinces Caatinga (Cerrado, Parana Forest (Pantanal+Chaco)). The uplift of the Brazilian Central Plateau in the Late Pliocene-Early Pleistocene (4-2 Myr BP) has been interpreted as a major event responsible for isolation and differentiation of biotas along these areas. However, we emphasize that without the establishment of a temporal framework concerning the diversification history of Tropidurus it is premature to correlate cladogenetic events with specific time periods or putative vicariant scenarios. The limiting factors hampering the understanding of the biogeographic history of this genus include (1) the absence of temporal references in relation to the diversification of distinct clades within Tropidurus; (2) the lack of an appropriate taxonomic resolution of the species complexes currently represented by widely distributed forms; and (3) the need for a comprehensive phylogenetic hypothesis. We suggest that these three important aspects should be prioritized in future investigations.

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Snakebites are still a critical public health problem in developing countries or isolated areas. In Brazil, the North Region has a high distribution coefficient worsened by the significant number of eventually unreported cases, due to difficulties in access to health services, to the natural geographic barriers and the vast territory. In the Rio Negro area, the species Bothrops atrox, Bothrops brazili, Lachesis muta muta and Bothriopsis taeniata are thought to be the major species responsible for snakebites. The aim of this study was to qualitatively and quantitatively determine the antigenic cross-reactivity and expression of toxins and the immunogenicity of Bothrops venom species of the Amazon and to evaluate the general efficacy of the therapeutic sera. The in vivo assays demonstrated that the defibrinating activity of B. taeniata venom was absent but that the lethal and hemorrhagic properties were more intense than in the B. atrox venom. The results evidence venom variability among the two B. atrox populations from two distinct Amazonian regions, which may reveal a subjacent speciation process. The results point to new aspects that may guide the improvement of anti-Bothropic therapeutic serum.

The dipsadine snake Leptognathus incertus was originally described from French Guiana and subsequently was restricted to the Atlantic Rain Forest in southeastern and south Brazil. We compare its original description with available data for Leptognathus alternans as well as with species of the genus Dipsas occurring in French Guiana. Leptognathus alternans is revalidated in the combination Dipsas alternans, representing the populations occurring in the Atlantic Rain Forest of southeastern and south Brazil. The neotype of L. alternans is designated and described. The taxonomic status of L. incertus is revised and, in the interest of stabilizing the nomenclature of this species, Dipsas copei is synonymized with L. incertus in the combination Dipsas incerta, corresponding to populations of the Guianan region. The holotype of L. copei is designated as the neotype of L. incertus. Resumo.A serpente dipsadínea Leptognathus incertus foi descrita originalmente da Guiana Francesa e posteriormente restrita à Floresta Atlântica no sudeste e sul do Brasil. Comparamos sua descrição original com os dados disponíveis de Leptognathus alternans, bem como com espécies do gênero Dipsas que ocorrem na Guiana Francesa. Leptognathus alternans é revalidada sob a combinação Dipsas alternans, representando as populações que ocorrem na Floresta Atlântica do sudeste e sul do Brasil. O neótipo de L. alternans é designado e descrito. O status taxonômico de L. incertus é revisado e, no interesse da estabilização da nomenclatura desta espécie, Dipsas copei é sinonimizada com L. incertus sob a combinação Dipsas incerta, correspondendo às populações da região das Guianas. O holótipo de L. copei é designado como o neótipo de L. incertus.

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