Three Ilyarachna species (Isopoda: Asellota: Munnopsidae) showing different bathymetric distributions in Japan and Kuril-Kamchatka Trenches, with descriptions of two new species
Abstract
The munnopsid genus Ilyarachna G. O. Sars, 1869 is one of the “swimming asellotes” that have paddle-shaped natatory pereopods. It comprises 46 species, most of which exhibit narrow geographic but broad vertical distributions. In this study, we morphologically and molecularly investigated Ilyarachna isopods collected from depths of 2886–7288 m in the Japan and Kuril-Kamchatka Trenches. These specimens include three morphospecies: Ilyarachna cf. kussakini, Ilyarachna abyssalis sp. nov., and Ilyarachna hadalis sp. nov., the latter two of which have been described here as new species. Kimura 2-parameter (K2P) distances among cytochrome c oxidase subunit I (COI) sequences from the three species were 16.5–17.2% (I. cf. kussakini vs. I. abyssalis sp. nov.), 14.8–16.1% (I. cf. kussakini vs. I. hadalis sp. nov.), and 6.2–7.7% (I. abyssalis sp. nov. vs. I. hadalis sp. nov.), respectively, whereas intraspecific K2P distances were less than 4%. The species were collected at different depth zones (2886–3519 m; 4026–6131 m; and 5976–7285 m) around the two trenches, ……
Read the original article on Deep-Sea Research Part I : Oceanographic Research Papers
Article inforamation
Mizuki Ohta, Keiichi Kakui, Shigeaki Kojima, Michitaka Shimomura, Three Ilyarachna species (Isopoda: Asellota: Munnopsidae) showing different bathymetric distributions in Japan and Kuril-Kamchatka Trenches, with descriptions of two new species, Deep Sea Research Part I: Oceanographic Research Papers, Volume 230, 2026
DOI : 10.1016/j.dsr.2026.104719
