Review of the Septibranchia (Mollusca: Pelecypoda) from the deep sea of Campos Basin, Brazil: Family Lyonsiellidae, with description of a new species

Abstract

A review is made of the members of Lyonsiellidae present on the continental slope (750-2000 m) of Campos Basin (22°S), off south-eastern Brazil. A total of six taxa are recognized. Two taxa were previously unknown to science (Lyonsiella pipoca n. sp., described herein, and Policordia sp.). Lyonsiella frielei and Policordia gemma are recorded from Brazilian waters for the first time. Lyonsiella abyssicola is distributed throughout the Atlantic Ocean, but the present record fills a gap in its distribution in the southwest Atlantic. Lyonsiella cf. formosa has a confused taxonomic status, and we believe that more than one species has been called L. formosa. Lyonsiella abyssicola, L. frielei and L. cf. formosa have the shell surface covered by small spines that typically have a hexagonal column and a stellate structure at the distal end.

Keywords

• bivalvia
• anomalodesmata
• lyonsiellidae
• south-west atlantic
• taxonomy
• deep-sea