Tail autotomy and regeneration are perhaps the most dramatic adaptations to enhance survival among lizards. In spite of much work on the subject, the ecological significance of tail autotomy rates in natural populations remains elusive, due to difficulties in controlling several confounding factors and the paucity of accurate demographic data. On the basis of a capture-recapture study, we investigate the ecological determinants of tail autotomy rates in Micrablepharus atticolus, a bluetailed lizard from the South American Cerrado. We tested whether habitat (as a proxy of predation intensity), seasonality (as a proxy of intensity of social interactions), ontogeny and sex affected autotomy rates, and also whether autotomy rates affected body condition. We found that tail autotomy rates in M. atticolus are lower than in many other species with brightly colored tails, likely resulting from a small body size and fossorial habits. Autotomy rates were lower than expected by chance in the plot with lower mortality rates, suggesting a more prominent role of predation intensity instead of predator efficiency, and increased with age, suggesting cumulative effects of predation attempts along the ontogeny or age-specific differences in predation intensity. We also found no intersexual differences or any effect of breeding activity on autotomy rates. Our results indicate that energetic costs of tail autotomy are low, or that animals compensate tail loss with increased foraging rates. These characteristics of M. atticolus seem tightly associated with its small body size, fossorial lifestyle and very short life span, and suggest that the costs of tail regeneration should be low.

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We describe a specimen of Apostolepis phillipsi Harvey, 1999, from Vila Bela da Santíssima Trindade, Mato Grosso, establishing the first unambiguous record of the species in Brazil. The new locality is ca. 120 km from the type locality, in Bolivia. We present an updated species diagnosis, the first image of a living specimen, and the first description of A. phillipsi coloration in life. Even though the Brazilian range of A. phillipsi lies within a protected area (Parque Estadual Serra Ricardo Franco—PESRF), it is threatened by cattle raising, logging and agriculture. PESRF lacks formal delimitation and a management plan, and the Mato Grosso State Legislature is considering a decree to extinguish PESRF, which could cause the extirpation of the Brazilian range of several endemic species.

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