Comparative morphology of integument and cutaneous glands of species of toads and salamanders from South America and North America

Abstract

The presence of venom glands in the skin is a feature shared by all current amphibians. These glands are distributed throughout the body or grouped together in large numbers, forming macroglands, such as the parotoids, which are structures used for defense against predators mainly found in toads (Anura: Bufonidae) and salamanders (Caudata). In addition to the parotoids, some frogs display macroglands in other regions of the body. This is the case of the Brazilian toad Rhinella jimi from the semi-arid region, which have macroglands both in the posterior and anterior members and is being studied by our research group. The North American species Incilius alvarius is widespread in regions of the Colorado River and of the Sonoran Desert and resembles R. jimi by having macroglands in the same regions of the body and inhabiting in an environment with water restriction periods. These two species are therefore a good model for the comparative study of evolutionary aspects of toads in relation to the use of macroglands for defense and to their strategies for dealing with water balance. Furthermore, taking advantage of the US diversity of salamanders and the opportunity of visiting the laboratory of Dr. Edmund D. Brodie, one of the world's experts in these animals, we also intend to study the morphology of salamander parotoids, comparatively to toads, using the species Ambystoma gracile as a model. The grant will be a great opportunity for professional and personal improvement of the student and will enable exchanging of knowledge between laboratories and research groups through the development of joint projects with widely recognized experts of the international herpetological community. (AU)