Morfologia e taxonomia das espécies do gênero Discosoma Ruppell & Leuckart, 1828 (Cnidaria, Corallimorpharia) no Brasil

Abstract

This work aims to describe the species of the genus Discosoma Rüppell & Leuckart, 1828 (Corallimorpharia, Discosomatidae), from the Brasilian coast. There is only one record of the species Discosoma carlgreni (Watzl, 1922) in the north of Espirito Santo, Brazil ( SCHLENZ & BELÉM, 1892). Since then no other discosomatid has been recorded from the Brazilian shore. Two species belonging to the genus Discosoma have been studied: D. carlgreni (Watzl, 1922) and D. sanctithomae (Duchassaing & Michelotti, 1860). Moreover, other samples exchanged from foreign institutions were examined. The systematic was based on external morphology, anatomy, microanatomy as well as a cnidom qualitativa study. The cnidae were classified according to SCHMIDT (1969, 1972, 1974) and HART0G (1980). The study of cnidom allowed to distinguish the two species on the basis of their discal tentacle, marginal tentacle, column and pharynx. Such features had not been utilized in previous works. Externally D. sanctithomae differs from D. carlgreni especially due to the presence of a smooth, transparent, peripherial zone, separating the discal tentacles from the marginal ones. D. car7greni was found in several places on the brazilian coast such as in the south of Espírito Santo, south of Bahia as well as in the Abrolhos Archipelago. The D. sanctithomae on the other hand was only be found in the Caribean islands and Abrolhos Archipelago.