Two New Caridean Shrimps of the Family Alvinocarididae (Crustacea, Decapoda) from a Hydrothermal Field at the Minami-Ensei Knoll in the Mid-Okinawa Trough, Japan

Abstract

Seventy-two specimens representing two new species of Alvinocaris of the family Alvinocarididae, A. brevitelsonis and A. leurokolos, were found in samples collected from thermally influenced fields at the Minami-Ensei Knoll (28°23.35'N, 127°38.38'E, 705m depth). The shrimps appeared to be the co-dominant macroinvertebrates in the small hollows of chimneys and among the mussel beds, bathing directly in vent fluids in the high temperature hydrothermal field. A key to the seven known species of Alvinocaris is given.