Geographic Variation in Brazillian Species of Hyla

Abstract

Until now, practically all Brazilian species of Hyla have been described or discussed exclusively under the nominative form, without regard for geographical variation. The subspecies is almost unknown in the systematics of Brazilian frogs. This paper is concerned with local variation in two difficult groups, that of Hyla catharinae and of the species Hyla polytaenia. Variation becomes apparent on extension of the known distribution, going from altitudinal forms to subspecies in isolated or peripheral parts of the range. Altitudinal variation was first pointed out by the author (1952) for Hyla circumdata Cope when specimens of this montane coastal species were collected above 1,800 meters on the Itatiaia Mountains. They were robust, and lacking the specific pattern of dark violet circles on a lighter blue-violet background on thigh parts which were concealed in repose. These colors were substituted by a uniform purplish-black, or slate colored surface. A new subspecies was not set up because some robust specimens from slightly lower elevations at Itatiaia, and elsewhere, showed vestiges of the circles.