Studying species interactions in nature often requires elaborated logistics and intense fieldwork. The difficulties in such task might hinder our ability to answer questions on how biotic interactions change with the environment. Fortunately, a workaround to this problem lies within scientific collections. For some animals, the inspection of preserved specimens can reveal the scars of past antagonistic encounters, such as predation attempts. A common defensive behaviour that leaves scars on animals is autotomy, the loss of a body appendage to escape predation. By knowing the collection site of preserved specimens, it is possible to assess the influence of organismal biology and the surrounding environment in the occurrence of autotomy. We gathered data on tail loss for 8189 preserved specimens of 33 snake and 11 amphisbaenian species to investigate biological and environmental correlates of autotomy in reptiles. We applied generalized linear mixed effect models to evaluate whether body size, sex, life‐stage, habitat use, activity pattern, biome, tropicality, temperature and precipitation affect the probability of tail loss in limbless reptiles. We observed autotomy in 23.6% of examined specimens, with 18.7% of amphisbaenian and 33.4% of snake specimens showing tail loss. The probability of tail loss did not differ between snakes and amphisbaenians, but it was higher among large‐sized specimens, particularly in adults and females. Chance of tail loss was higher for diurnal and arboreal species, and among specimens collected in warmer regions, but it was unaffected by biome, precipitation, and tropicality. Autotomy in limbless reptiles was affected by size‐dependent factors that interplay with ontogeny and sexual dimorphism, although size‐independent effects of life‐stage and sex also shaped behavioural responses to predators. The increase in probability of tail loss with verticality and diurnality suggests a risk‐balance mechanism between species habitat use and activity pattern. Although autotomy is more likely in warmer regions, it seems unrelated to seasonal differences in snakes and amphisbaenians activity. Our findings reveal several processes related to predator–prey interactions involving limbless reptiles, demonstrating the importance of scientific collections to unveil ecological mechanisms at different spatio‐temporal scales.

Although the recent advances on the relationship of its major groups, the systematics of the rich fauna of Neotropical snakes is far from being a consensus. In this sense, derived groups presenting continental distributions have represented a main challenge. The taxonomy of the snake tribe Echinantherini is one of the most contentious among the diverse family known as Dipsadidae. The tribe is poorly sampled in phylogenetic studies, resulting in conflicting hypotheses of relationships among its taxa. Moreover, several rare and micro endemic species of Echinantherini have never been evaluated within a comprehensive phylogenetic framework. Here, we assess for the first time the phylogenetic position of the rare Echinanthera amoena within Echinantherini. We based our analyses on a comprehensive multilocus dataset including 14 of the 16 species described for the tribe. Our results support the monophyly of Echinantherini and strongly indicate E. amoena as a unique lineage, phylogenetically positioned apart from all other congeners. From the three current genera (Echinanthera, Taeniophallus, and Sordellina) our results indicate that Echinanthera and Taeniophallus are paraphyletic, since the T. affinis species group is positioned as sister to Echinanthera (except E. amoena) clustering apart from the clade formed by the T. brevirostris and T. occipitalis groups. We describe new genera for the T. affinis and T. occipitalis species groups and an additional monospecific genus for E. amoena. Although we did not evaluate the phylogenetic position of T. nebularis, we described a new genus and removed it from Echinantherini since its morphology strikingly departs from all species now included in the tribe. Finally, we redefine the genera Echinanthera and Taeniophallus and we provide comments about further directions to study the biogeography and the evolution of morphological traits in Echinantherini.

We recorded a second specimen of the poorly known insular blind snake Liotyphlops caissara. This new specimen expands the morphological variation of the number of dorsal scales in the genus Liotyphlops to 296 (vs. 304 in L. wilderi) and, considering the fact that the holotype of this species was destroyed, the present specimen represents the only available L. caissara individual in zoological collections. Also, this new record constitutes the first out of type locality and expands the distribution of the species in about 40 km to the northeastern. According to IUCN criteria (B1a, b [iii]), we suggest that L. caissara be included in the "Endangered" category, since it occurs in only two insular locations and exhibits an occurrence extension of <5,000 km² (about 355 km 2).

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