A COMPARISON BETWEEN HEAD AND BODY SKIN SECRETION IN CASQUE-HEADED TREE-FROGS AND CLOSELY RELATED SPECIES

JARED C.(1), MARQUES-PORTO R.(1), ONO R.K.(1), LOPES-FERREIRA M.(2), BOLETINI-SANTOS D. (2), FAIVOVICH J. (3), RODRIGUES M.T. (4), HADDAD C.(3), ANTONIAZZI M.M. (1)

(1) Lab. Biologia Celular, (2) LETA, Instituto Butantan, (3) Depto. Zoologia, UNESP, Rio Claro, (4) Depto. Zoologia IB-USP

Corythomantis greeningi (Cg), Aparasphenodon brunoi (Ab),  are casque-headed tree-frogs characterized by a flat and co-ossified head associated with defense against predators and/or dessication.  Itapotihyla langsdorfii (Il), and Trachycephalus venulosus (Tv) are related to these two taxa, but do not have such a modified skull structure. It is known that Cg and Ab present fragmotic behavior, which consists in entering the body backwards into holes and using the head as a lid. Tv, as Cg, when harassed, releases a copious and sticky cutaneous secretion but, similarly to Il, does not present phragmotic behavior. In this work we compared the electrophoretic profiles of body and head secretions of the four species relating results to their natural history and phylogenetic relationships. All species showed differences between head and body secretions, but Ab was most clear in this respect, with several bands appearing only in the body secretion, particularly between 18 and 25 kDa, while Cg showed the larger similarity between body and head secretions, presenting specific 18 and 30kDa bands. Both Il and Tv present similar profiles in head and body with major characteristic bands around 60 kDa in Il and 45 kDa in Tv. A comparison among the electrophoresis profiles showed that the secretions of Cg and Ab share more bands, followed by Pv and, at last, Il. These results seem to be in accordance to the phylogenetic hypothesis of the casque-headed tree-frogs. It is noticeable that the species presenting the largest difference between body and head is the one presenting the most well characterized fragmotic behavior, living inside bromeliads in the sand bar.

KEY WORDS: Amphibia, Hylidae, casque-headed frogs, skin secretion

FINANCIAL SUPPORT: FAPESP, CNPq, FUNDAP

CORRESPONDENCE TO: C. Jared, Instituto Butantan, Av. Vital Brasil, 1500, São Paulo, 05503-900, Phone: + 55 11 3726-7222, ext. 2234. Email: jared@usp.br