Vesicomyicola trifurcatus, a new genus and species of commensal polychaete (Annelida: Polychaeta: Nautiliniellidae) found in deep-sea clams from the Blake Ridge cold seep

摘要

A new genus and species of deep-sea polychaete belonging to the family Nautiliniellidae is described from the Blake Ridge cold seep off the coast of South Carolina at a depth of 2155 m. This species is commensal within the mantle cavity of -60% of the vesicomyid clams collected at the seep site. Vesicomyicola trifurcatus is distinguished from previously described nautili-niellid genera and species by the presence of two pairs of tentacular cirri and up to seven trifurcate hooked chaetae on the posterior parapodia. The new species resembles Iheyomytilidicola tridentatus in having trifurcate hooks, but the arrangement and number of chaetae differs. Only two types of chaetae are present in V. trifurcatus: four to seven stout, simple hooks anteriorly to mid-body, and up to seven trifurcate hooks posteriorly. In contrast, there are three types of chaetae in l. tridentatus: up to five stout hooks per parapodium, each with a minute projection on cutting edge of the main fang, 10-20 simple, slender tridenate chaetae, and numerous minute mucronate chaetae. A key to species of Nautiliniellidae is included.