Abstract

A new interstitial acrocirrid, Actaedrilus yanbarensis gen et. sp. nov., is described from Okinawa-jima Island, Japan. Individuals of the new genus and species were collected from the interstices of subtidal coarse sand (about 1 m depth). The new genus is comprised of the new species and A. polyonyx (Eliason, 1962) comb. nov. and it is characterized by the presence of two pairs of long branchiae, non-retractile head, minute body, and short club-shaped palps. We infer the phylogenetic position of A. yanbarensis gen. et sp. nov. within Acrocirridae using five gene markers (COI, 16S, 18S, 28S, Cyt B).