Exploration of the southern part of the East Pacific Rise during the 1993 Naudur French cruise between 17°S and 19°S revealed the presence of numerous crabs at several hydrothermal sites. Two species were collected: Bythograea thermydron Williams, previously known from areas further north on the ridge, and a new species, B. laubieri sp. nov. The strong ocular reduction of B. laubieri recalling the one of B. microps de Saint Laurent, this small species is redescribed, based on both the female holotype and new specimens collected from 9°50'N and 13°N areas (Hot 96 cruise), including an adult male. A key to the three species B. thermydron, B. microps and B. laubieri is based on the morphological features. During the dives between 17° and 19°N, big crabs were observed analogous to the large species Cyanagraea praedator de Saint Laurent, previously recorded from more northern sites, -no specimen was sampled- and they are tentatively considered as Cyanagraea sp. An overview of all the bythograeid crabs distributed along the East Pacific Rise summarizes the known data.
Hydrothermal vents, East Pacifc Rise, Bythograeidae, Bythograea, B. thermydron, B. laubieri, B. microps, key to species, Cyanagraea, C. praedator, biogeography, ecology.