BULLETIN OF MARINE SCIENCE, 66(1): 1–11, 2000 1 TEDANIA BRASILIENSIS NEW SPECIES (DEMOSPONGIAE, POECILOSCLERIDA, TEDANIIDAE) FROM BRAZIL, WITH SOME REMARKS ABOUT THE GENUS TEDANIA IN THE TROPICAL SOUTHWESTERN ATLANTIC Beatriz Mothes, Eduardo Hajdu and Rob W. M. van Soest ABSTRACT Tedania brasiliensis n. sp. is described from widely disjunct localities along the Bra- zilian coast, distributed from ca 00°30'to ca 24°00'S, and from 3 to 54 m in depth. The species is distinguished from its closest relative in the tropical Western Atlantic, T. ignis (Duchassaing and Michelotti, 1864), by the possession of strongyles as the sole choanosomal megascleres, pinkish-red live-color, and notorious anti-yeast properties. No dermatitis is known yet from contact with the new species. Other records of the genus from the Brazilian coast are reviewed, and citations of T. anhelans (Lieberkuhn, 1859) and T. vanhoeffeni Hentschel, 1914, are all transferred to T. ignis. We tentatively assign the record of T. murdochi Topsent, 1904, to T. mucosa Thiele, 1905, but suggest the reten- tion of T. biraphidora (Boury-Esnault, 1973) as a valid species, distinct from T. patagonica Ridley and Dendy, 1886, in contrast to suggestions made in recent literature. The genus Tedania is not particularly diverse in the Atlantic Ocean in general (ca 10– 12 species), and this is the case on the Brazilian coast. Its taxonomic history in the latter area is, however, markedly puzzling. De Laubenfels’ (1956) dubious identification of a specimen from the coast of São Paulo, clearly illustrates the issue: “Tedania, perhaps ignis, perhaps anhelans, perhaps new species”. Our study, apart from describing a new species very close in spiculation to T. ignis (Duchassaing & Michelotti, 1864), revises the records of other species of Tedania cited for the Brazilian coast. A clearer picture of T. ignis’s morphospace ( morohological disparity) was gathered from an extensive series of specimens of the latter species, amply distributed along the tropical Western Atlantic (32°N–27°S). The Brazilian coastline is one of the least studied large warm tropical marine areas in the world with respect to its sponge fauna. Van Soest (1994) cited 234 published records of demosponges for the area, less than half of the number of current conservative estima- tions of the true number of species (ca 600–700 morphospecies; Hajdu et al., in press). A greater committment to the taxonomy of Brazilian marine sponges is, nevertheless, tak- ing place at the moment, as inferred from the diverse origin of the specimens cited below. The specimens which serve as the basis for the descriptions stem from three independent but extensive faunistic surveys on disjunct sections of the Brazilian coastline (Muricy et al., 1991; Hajdu et al., 1996; Mothes, 1996). Several new records of demosponges will be published in the next few years from material gathered in these surveys, as well as from ongoing collecting efforts (Lana, 1996; Lerner, 1996; Hajdu et al., in press), at local, state and national levels.