A DEEP-SEA HYDROTHERMAL VENT COMMUNITY DOMINATED BY STAUROMEDUSAE

A dense population of stauromedusan scyphozoans (morphologically simil ar to previously described species within the genus Lucernaria) was en countered in a previously undocumented area of hydrothermal activity a long the crest of the East Pacific Rise (Lat. 20 degrees 50.304'N; Lon g. 109 degrees 05.422'W; depth of 2605 m). A few galatheid (Munidopsis subsquamosa) and bythograeid (Bythograea thermydron) crabs and occasi onal anemones (Cyananthea sp.) were the only other vent-associated meg afauna observed within the region. This report represents: (1) the fir st documented occurrence of a biological community dominated by Stauro medusae at an active hydrothermal vent; (2) one of the deepest reporte d occurrences of Stauromedusae in the world's oceans; and (3) document ation of the existence of a species within a class (Scyphozoa) of orga nisms that thus far has not been reported from hydrothermal vents or o ther reducing environments. (C) 1998 Elsevier Science Ltd. All rights reserved.