A new marine tardigrade genus and species (Arthrotardigrada, Styraconyxidae) with unique pockets on the legs

Abstract

A marine heterotardigrade Cyaegharctus kitamuraigen. et sp. nov. (Arthrotardigrada, Styraconyxidae) is described from Daidokutsu, a submarine cave off Iejima island, Okinawa Islands, Ryukyu Archipelago, Japan. It is easily distinguished from all other styraconyxids by its pocket organs (putative sensory structures) on all legs in addition to the usual leg sensory organs. Its combination of other character states, such as the dorso-ventrally flattened body, ovoid primary clavae, conical secondary clavae, large terminal anus, internal digits with proximal pads and peduncles, external digits with developed peduncles and all digits with three-pointed claws in adult female, supports the erection of a new genus and species.

Three new meiobenthic species from a submarine cave in Japan: Echinoderes gama, E. kajiharai and E. uozumii (Kinorhyncha: Cyclorhagida)

“…According to Omori et al (2010), the cave has been completely submerged for 8000 years, under the influence of the sea-level rising after the last glacial period. The floor of the cave is covered by a layer of muddy sediment and many animals of various taxa have been found from the cave, for example, Tardigrada (Fujimoto, 2015;Fujimoto et al, 2017;Fujimoto & Jimi, 2020), Ostracoda (Tabuki & Hanai, 1999;Chiu et al, 2017), Mysida (Hanamura & Kase, 2001) and Mollusca (Kase & Hayami, 1992). The kinorhynch Ryuguderes iejimaensis has recently been described from this cave (Yamasaki, 2016).…”