A new species of Pseudorimula (Fissurellacea: Clypeosectidae) from hydrothermal vents of the Mid-Atlantic Ridge

Pseudorimula midatlantica new species is described from the Snake Pit hydrothermal lield on the Mid-Atlantic Ridge It is the second member of its genus, the type species being known Irom the Mariana Trough h)drothermal vents in the mid-Pacific It differs from the type species in its hypertrophied development of the gonad, which displaces part of the space normally occupied by the foot on the left side; correspondingly, the posterior shell muscle of the type species is merged with the right shell muscle in P. midatlantica.Other differences are that it has three rather than six pairs of epipodial tentacles.The new species also provides evidence of faunal interchange between widely separated ridge systems.