A new caridean shrimp of the family Alvinocarididae from thermal vents at Menez Gwen on the Mid-Atlantic Ridge

摘要

A new species of alvinocaridid shrimp, Alvinocaris williamsi, is described from the Menez Gwen hydrothermal vent field on the Mid-Atlantic Ridge. The new species is most similar to another relatively shallow water alvinocaridid, A. stactophila Williams, known only from a cold seep area off the coast of Louisiana, but differs in details of the rostrum and appendages. Alvinocaris williamsi is also morphologically similar to two species of the genus recently described from the Mid-Okinawa Trough, Japan. Molecular phy-logenetic studies of A. williamsi, the eighth described member of the genus, may provide significant insights into the role that deep-sea hydrothermal vents at mid-ocean ridges and hydrocarbon seeps on continental margins have played in the evolution of fauna endemic to these chemosynthetic habitats.