Simple SummaryIntraspecific interactions are known to affect habitat use in birds and mammals but their role in spatial ecology of reptiles is far less recognized. Our comparative study shows that species known to exhibit intraspecific predation (smooth snake Coronella austriaca) express clearly different patterns of habitat and shelter occupancy than a species with no such cannibalistic behavior (slow worm Anguis fragilis). Specifically, juvenile smooth snakes prefer sites and shelters not occupied by the adults, even despite suboptimal habitat conditions. We propose that such division indicates an avoidance of predation pressure set by larger individuals on the younger and smaller ones. On the contrary, in slow worms no tendency for intraspecific avoidance are observed, since specimens of different ages commonly share the same area and shelters. This points to higher flexibility in habitat use in slow worms, while the smooth snake population is spatially structured, with juveniles dispersed to the margins of the population range. For endangered smooth snakes, habitat conservation should therefore include a wide buffer zone to maintain the youngest fraction of the population. Future studies on habitat utilization in squamates needs to pay more attention to the social cues, a commonly overlooked aspect in the spatial ecology of reptiles.AbstractReptiles undergo worldwide decline driven mostly by habitat change. Detailed recognition of factors underlying spatial structure and habitat utilization is therefore a prerequisite of effective conservation of this group. While the body of data on spatial ecology of reptiles is rapidly growing, studies on social factors remain still underrepresented. We studied age-specific patterns of shelter use, range size, and habitat preferences in the context of intraspecific interactions in the smooth snake Coronella austriaca—known to exhibit intraspecific predation—and the limbless lizard slow worm Anguis fragilis—with no such behavior observed. Despite smaller availability of preferred microhabitats, juveniles of smooth snakes occupied habitat and shelters located at the edge of the population range that did not overlap with adults. No such pattern was observed in the slow worm. Our study indicates that intraspecific interactions affect the spatial ecology of squamates. Passive and active protection of habitat must include wide buffers to preserve the poorly detectable young fraction of the population.

ABSTRACT. Palatal dentition in lizards is incompletely known, especially data on its variability are scarce. We studied variation in the number of pterygoid teeth in three species of Podarcis, a species-rich genus of lacertid lizards: terrestrial, P. siculus and saxicolous, P. erhardii and P. cretensis. In contrast to some previous studies, we found no sexual dimorphism in the number of palatal teeth in any of these species. The number of teeth was not correlated to lizard size. In our sample, P. cretensis on average had more teeth than did P. erhardii but fewer than did P. siculus. In addition, some specimens of P. cretensis and P. siculus showed asymmetry in the number of pterygoid teeth, which may be a result of anthropogenic pressure. The observed variability in the occurrence of palatal dentition illustrates the importance of scoring this character in phylogenetic analyses only on the basis of a sufficient sample.

Sand lizards (Lacerta agilis) exhibit a clear pattern of sexual dimorphism, both in coloration and body proportions, where males have larger heads and are longer-legged at a given snout-to-vent length (SVL). In this study we analyse allometry of skull growth with SVL and skull length (SL) as references. The sand lizard skull is basically sexually size dimorphic and there are only minor shape differences. When SVL is used as a reference point, it generates differences in all traits to be measured, presumably because SVL is subject to different and strong selection pressures in both sexes. When skull length is taken as a reference point, differences in skull shape are restricted only to the postorbital region, which is wider in males. This may reflect selection pressure on stronger bite force in males.

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