Ethusina SMITH 1884

Remarks. – The genus Ethusina Smith, 1884 (type species Ethusina abyssicola Smith, 1884) currently contains 21 recognised species from the Atlantic and Indo-Pacific regions, and is characterised by their relatively small eyes which are immovable in the orbit and the large basal antennular segment. Othewise, they are very close to members of the Ethusa Roux, 1830. Although there had been some early uncertainty with the validity of Ethusina, the above-mentioned characters, however, appear to work (at least for the time being) and we continue to use them to distinguish the two genera.

Thirteen Ethusina species are presently known from the Indo-West Pacific, viz., E. bicornuta Chen, 1997, E. brevidentata Chen, 1993, E. challengeri (Miers, 1886), E. desciscens Alcock, 1896, E. dilobotus Chen, 1993, E. gracilipes (Miers, 1886), E. investigatoris Alcock, 1896, E. longipes Chen, 1987, E. microspina Chen, 2000, E. paralongipes Chen, 1993, E. pubescens Chen, 1993, E. robusta (Miers, 1886), and E. vanuatuensis Chen, 2000. The present paper adds six more new species. More than half of the currently recognised Ethusina species have been described only in the last decade or so, testimonial to their diversity in the deep-sea environment. More new species of Ethusina are also present in Australia and will be described in the near future (see Davie, 2002). Despite this, the Ethusinae is in urgent need of a worldwide revision, and there are still a good number of misidentifications and new species to be resolved. Nevertheless, a complete revision of the subfamily Ethusinae which has only three genera but some 62 recognised species and almost 70 available names worldwide, will be a massive task and cannot be finished in the near future. On the basis of the published literature at least, the new taxa described here seem to be distinct and it is on this belief that we formally name them.