Species in Fissurellidae (Gastropoda) from the North Atlantic with a focus on the Azorean seamounts

Various reviews of families in Mollusca have indicated a large diversity and a high degree of endemicity on the Azorean seamounts. In this study, bathyal species in the gastropod family Fissurellidae have been investigated using material collected during the M151 cruise conducted by R/V Meteor in 2018 to seamounts south of the Azores. Additional records were incorporated from literature including a review of some species in the subfamily Fissurellinae from the cruise seamount 2 in 1997 and from northern Atlantic species in the collection at Senckenberg am Meer (Wilhelmshaven). Fourteen species are herein reported from the Azorean seamounts of which twelve species were found during M151; Puncturella asturiana (P. Fischer, 1883) and Profundisepta alicei (Dautzenberg & H. Fischer, 1897) were not recorded in this cruise. The distributions of the poorly-known, yet common,

Puncturella fornicata Locard, 1898 and Puncturella agger R. B. Watson, 1883 are presented. Profundisepta luciae spec. nov. is proposed; this species is the only fissurellid endemic to the Azorean seamounts. The degree of endemism in Fissurellidae is much lower (7%) on the Azorean seamounts

than in other recently reviewed species in Veti- and Caenogastropoda (40-100%). Nearly 50 % of the fissurellids have an amphi-Atlantic distribution. It is unclear how most species have distributed over large areas considering their direct or short lecitotrophic larval development. Their relatively large foot to body mass ratio possibly facilitated planktonic rafting and may have enabled long-distance migrations.