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Predator–prey interactions are important evolutionary drivers of defensive behaviors, but they are usually difficult to record. This lack of data on natural history and ecological interactions of species can be overcome through museum specimens, at least for some reptiles. When facing aggressive interactions, reptile species may exhibit the defensive behavior of autotomy by losing the tail, which is also known as “urotomy”. The inspection of preserved specimens for scars of tail breakage can reveal possible ecological and biological correlates of urotomy. Herein, we investigated how the probability of urotomy in the worm lizard Amphisbaena vermicularis is affected by sex, body size, temperature, and precipitation. We found higher chances of urotomy for specimens with larger body size and from localities with warmer temperatures or lower precipitation. There was no difference in urotomy frequency between sexes. Older specimens likely faced – and survived – more predation attempts through their lifetime than smaller ones. Specimens from warmer regions might be more active both below‐ and aboveground, increasing the odds to encounter predators and hence urotomy. Probability of urotomy decreased with increased precipitation. Possibly, in places with heavier rainfall worm lizards come more frequently to the surface when galleries are filled with rainwater, remaining more exposed to efficient predators, which could result in less survival rates and fewer tailless specimens. This interesting defensive behavior is widespread in squamates, but yet little understood among amphisbaenians. The novel data presented here improve our understanding on the correlates of tail breakage and help us to interpret more tales of lost tails., Preserved specimens can be used to improve our understanding on the behavioral ecology of reptiles. In inspecting scars of tail breakage in preserved specimens of worm lizards, the chances of tail loss increased with body size and temperature, and decreased with precipitation. Tail loss was not affected by sex, suggesting similar predation pressure on both male and female worm lizards.

Although we have a good understanding of how predation can influence community structure, we still have little information about how predation by visually oriented birds can be a significant source of mortality for reptiles. We observed adults of Guira guira feeding their offspring with four different species of reptiles, namely Amphisbaena vermicularis, Copeoglossum nigropunctatum, Iguana iguana and Tropidurus torquatus. It is the first report of G. guira predation on A. vermicularis and C. nigropunctatum. Although G. guira has been recognized as insectivorous, we believe that predation of small cryptozoic reptiles is a common event during bird breeding season.Keywords: Amphisbaena vermicularis, Copeoglossum nigropunctatum, cryptozoic reptiles, predation strategy, Pantanal.

Visceral anatomy of amphisbaenids Amphisbaena vermicularis Wagler, 1824; Anops kingii Bell, 1833; Aulura anomala Barbour, 1914; Bronia bedai Vanzolini, 1991; Cercolophia cuiabana Strüssmann & Carvalho, 2001, and Leposternon microcephalum Wagler, 1824 were comparatively described and the size and the position of the organs in the pleuroperitoneal cavity was established in relation to the ventral scutellation. The main results were: the right lung presents different degrees of size reduction compared to the left lung, being conspicuous only in A. anomala, and L. microcephalum; the limit between small and large intestines is clear due to the presence of a caecum; the right lobe of the liver is larger than the left one, but its length varies within the same species and among species; the right gonad occupies a more cranial position in relation to the left one, in all six studied species; the right ovary is also larger than the left one in all studied specimens, whereas the left testicle can be larger or of the same size as the right one in some specimens; the shape of the testicles varies from elongated, kidney-shaped or oval; kidneys are symmetrically positioned at the caudal portion of the pleuroperitoneal cavity and one kidney can be larger than the other.

Amphisbaena arda sp. nov. is described based on a specimen obtained at Mocambo do Vento, on the left bank of the São Francisco river, Bahia state, Brazil. A. arda is a medium size amphisbaenian with a checkered black and white color pattern similar to the one present in the fuliginosa group but differing from that by having a lighter pigmentation, an uniformly white ventral surface, and by several other important morphological characters. A. arda is similar to Amphisbaena vermicularis in meristic characters currently used to assist amphisbaenian identification but can be separated from it by its color pattern, its flatter cephalic shields, and by the more ventral position of the nostril.