摘要：

The scincids Mabuya macrorhyncha and M. agilis occur sympatrically and syntopically at the Barra de Marica restinga, in Rio de Janeiro State, Southeastern Brazil. The use of three different niche dimensions (space, food, and time) by the two species was compared and certain morphometric differences between them were analyzed. The two species differed considerably in microhabitat use both horizontally and vertically. Mabuya macrorhyncha was strongly associated with bromeliads, while M. agilis was found mainly on the leaf-litter and had a low degree of arboreality. Both species had a unimodal activity pattern with a peak between 0900 and 1200 h. The two species also differed in diet composition by volume and by number of prey ingested (although spiders and cockroaches are important items in the diets of both), but did not differ in mean prey size. We also observed morphological differences between the two species, which are presumably associated with their differential microhabitat preference: Mabuya macrorhyncha had greater mean values of hand plus finger length than M. agilis, which had greater values of head height and body height. The longer fingers and more flattened body plan of M. macrorhyncha probably allow, respectively, a greater degree of arboreality and more efficient movements between tough bromeliad leaves compared to the ground-dwelling M. agilis. We concluded that the two species of Mabuya at Barra de Marica differ mostly in microhabitat use (compared to other ecological aspects we studied) and that such differences in the horizontal and vertical use of the spatial niche are closely related to some morphological differences.

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