Echiura from Antarctic and adjacent waters

Abstract

A collection of 555 Echiura from the far southern seas made by American research vessels (1962–1986) yielded 9 species. An illustrated key and morphological notes are provided. Geographical ranges of these taxa are expanded, but only one (Protobonellia nikitini) is new to Antarctica. The large number of specimens allows a more complete description of certain characters, e.g., for Echiurus antarcticus. Biometric analyses showed the delayed ontogeny of gonoducts, but early appearance of anal vesicles. Previously reported Antarctic echiurans not found in this study are discussed and two putative taxa of Salvini-Plawen are considered no longer valid (E. torulobotus=E. antarcticus and Binoraphorus geminolobotus=species inquirendum). Zoogeographical analysis shows no differential distribution along horizontal gradients, but depth is important. The Echiuridae prefer sub-littoral and shallow bathyal water while the Bonelliidae are more common at bathyal and abyssal depths.