Comprehensive assessments of species’ extinction risks have documented the extinction crisis¹ and underpinned strategies for reducing those risks². Global assessments reveal that, among tetrapods, 40.7% of amphibians, 25.4% of mammals and 13.6% of birds are threatened with extinction³. Because global assessments have been lacking, reptiles have been omitted from conservation-prioritization analyses that encompass other tetrapods^4–7. Reptiles are unusually diverse in arid regions, suggesting that they may have different conservation needs⁶. Here we provide a comprehensive extinction-risk assessment of reptiles and show that at least 1,829 out of 10,196 species (21.1%) are threatened—confirming a previous extrapolation⁸ and representing 15.6 billion years of phylogenetic diversity. Reptiles are threatened by the same major factors that threaten other tetrapods—agriculture, logging, urban development and invasive species—although the threat posed by climate change remains uncertain. Reptiles inhabiting forests, where these threats are strongest, are more threatened than those in arid habitats, contrary to our prediction. Birds, mammals and amphibians are unexpectedly good surrogates for the conservation of reptiles, although threatened reptiles with the smallest ranges tend to be isolated from other threatened tetrapods. Although some reptiles—including most species of crocodiles and turtles—require urgent, targeted action to prevent extinctions, efforts to protect other tetrapods, such as habitat preservation and control of trade and invasive species, will probably also benefit many reptiles.

The effectiveness of pitfall traps associated with drift fences to capture amphibians and reptiles in three field studies, in Rio Grande do Sul (extreme southern Brazil), São Paulo (São Paulo, southeastern Brazil), and Amazonas (Amazonas, northern Brazil) is described. At Santa Maria, a total of 2040 amphibians and reptiles were caught in 30 pitfalls (200 L, with drift fence) during 18 months of study (capture efficiencies of 3.78 amphibians and reptiles/pitfall/month and 0.14 snake/pitfall/month). At Itirapina, São Paulo, 1262 amphibians and reptiles were obtained in 72 pitfalls (100 L, with drift fence) during six months (capture efficiencies of 11,9 amphibians and reptiles/pitfall/month and 0,38 snake/pitfall/month). At Rio Pitinga, Amazonas, over 600 amphibians and reptiles were caught in 50 pitfalls (100-150 L, with drift fence) during three months (capture efficiencies of ca. 4.00 amphibians and reptiles/pitfall/month and 0.87 snake/pitfall/month). Capture efficiencies of 1.25 to ~3.92 amphibians and reptiles/pitfall/month were obtained in four other unpublished studies made by other authors in Brazil, all of them using 20-35 L traps, either with or without drift fences. Higher capture efficiencies for snakes were obtained in those studies in which larger containers (100-200 L) were used. The results presented here indicate that pitfall traps are extremely useful to sample amphibians and reptiles in Brazil, especially anurans and lizards. From these results, it is possible to preview the capture of 125 to 1200 amphibians and reptiles with 100 pitfalls during one month, regardless of the size of the pitfalls and sampling design of the trap arrays. The main advantages and disadvantages of the method and detailed guidelines on how to design, install, and use the traps is discussed

The Neotropical pitviper genus Bothrops comprises about 40 species, which occur in all main ecosystems of cis‐Andean South America. We explored the relationships of body size and form (tail length and stoutness) with macrohabitat use in 20 forms of Bothrops. Semi‐arboreal habits appeared only in forest forms. Semi‐arboreals are significantly more slender and have longer tails than terrestrials; body size is not significantly different between terrestrials and semi‐arboreals. Within Bothrops, independent contrasts for macrohabitat use were significantly correlated with contrasts of tail size (positively) and stoutness (negatively); thus, the more arboreal the species, the longer its tail and the more slender its body. Contrasts of adult body size seems to remain constant over the lower range of macrohabitat use, but to decrease in species of Bothrops which are more arboreal. Reconstructions of character states indicate that: (1) the ancestor of Bothrops was a small, stout, terrestrial species; (2) semi‐arboreal habits appeared one to three times in the genus; (3) a decrease in stoutness and an increase in tail length occurred along with an increase in arboreality in some clades. Although macrohabitat use seems to be important in determining body form in Bothrops, our results also indicate that tail size, stoutness and body size may also be affected by selective agents other than macrohabitat use. The selective agents responsible for the shifts in macrohabitat use in Bothrops are still uncertain, although they may have included prey availability and/or predation pressure. The plasticity of macrohabitat use, morphology and body size described in this study may have been key features that facilitated the highly successful ecological diversification of Bothrops in South America.