Ikedosoma (Annelida: Echiura: Thalassematidae) from the Tropical Pacific, with Description of a New Species

Abstract

A new species of the thalassematid echiuran Ikedosoma abemama sp. nov. is described based on a single specimen collected from Abemama Atoll, the Gilbert Islands, Kiribati. The species is particularly distinguishable from all congeners by the absence of the proboscis lower lip. A single specimen of Ikedosoma collected from Dam Bay, Nha Trang, Vietnam is also described, being similar to the new species, although its poor condition prevented a positive identification. The first confirmed records of Ikedosoma from the tropical Pacific Ocean are included (hitherto known only from temperate waters of Japan), in addition to a summary table of diagnostic characteristics and a dichotomous key to the species of Ikedosoma.