Caribbean Journal of Science, Vol. 41, No. 3, 583-599, 2005 Copyright 2005 College of Arts and Sciences University of Puerto Rico, Mayagu¨ez Two New Brittle Star Species of the Genus Ophiothrix (Echinodermata: Ophiuroidea: Ophiotrichidae) from Coral Reefs in the Southern Caribbean Sea, with Notes on Their Biology GORDON HENDLER Natural History Museum of Los Angeles County, 900 Exposition Boulevard, Los Angeles, California 90007, U.S.A.
[email protected] ABSTRACT.—Two new species, Ophiothrix stri and Ophiothrix cimar, inhabit shallow reef-platforms and slopes in the Southern Caribbean, and occur together at localities in Costa Rica and Panama, nearly to Colombia. What appears to be an undescribed species resembling O. cimar has been reported from eastern Venezuela. In recent years, reefs where the species were previously observed have deteriorated because of environmental degradation. As a consequence, populations of the new species may have been reduced or eradicated. The new species have previously been mistaken for O. angulata, O. brachyactis, and O. lineata. Ophiothrix lineata, O. stri, and O. cimar have in common a suite of morphological features pointing to their systematic affinity, and a similar pigmentation pattern consisting of a thin, dark, medial arm stripe flanked by two pale stripes. Ophiothrix lineata is similar to Indo-Pacific members of the subgenus Placophiothrix and closely resembles Ophiothrix stri. The latter is extremely similar to O. synoecina, from Colombia, and both can live in association with the rock-boring echinoid Echinometra lucunter. Although O. synoecina is a protandric hermaphrodite that reportedly broods its young externally, the new species are gonochoric and do not brood.