ISANTHUS HOMOLOPHILUS SP. NOV. (ISANTHIDAE, ACTINIARIA, ANTHOZOA) FROM FRENCH-POLYNESIA

A new deep-water Actiniaria species, Isanthus homolophilus sp. nov. is described from the French Polynesia. Morphological and ecological dif ferences between the new species and the other known species of the ge nus Isanthus are discussed. The distinct morphological characteristics that distinguish I. homolophilus, are the presence of a tentaculated columnar margin, the tentacle number (84-96), and its cnida biometry. A further ecological characteristic is the distinct symbiotic relation ship that the anemone exhibits towards the decapod Hypsophrys inflata. During the biological researches of the 'Service Mixte de Controle Bi ologique' (SMCB) in French Polynesia (1986-1990) at depths ranging fro m 100 to 1120 m, a symbiotic association between a deep-water homolid crab, Hypsophrys inflata Guinot & Richer de Forges, 1981 and a sea ane mone of the genus Isanthus (Actiniaria: Isanthidae) was collected. Eve n though this association was described by Guinot et al. (1995) and Ch intiroglou et al. (1996), no concise description of the anemone is giv en. Thus, the goal of the present study was to provide a detailed desc ription of the new anemone species and compare it with other species o f the Isanthidae Carlgren, 1938 family. The methodology followed in ou r investigation was that of Doumenc & Foubert (1984) and Doumenc et al . (1985). Nematocyst nomenclature used was as proposed by England (199 1). Abbreviations: MNHN (Museum National d'Histoire Naturelle Paris).