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A new genus and species of Tardigrada (Halechiniscidae: Euclavarctinae) from the deep sea of Okinawa Islands, Japan

Published online by Cambridge University Press:  16 February 2026

Shinta Fujimoto Open the ORCID record for Shinta Fujimoto [Opens in a new window] ,
Hiroshi Yamasaki Open the ORCID record for Hiroshi Yamasaki [Opens in a new window]  and
Susumu Ohtsuka
Shinta Fujimoto*
Affiliation:
Graduate School of Sciences and Technology for Innovation, Yamaguchi University, Yamaguchi, Japan
Hiroshi Yamasaki
Affiliation:
Faculty of Arts and Science, Kyushu University, Fukuoka, Japan
Susumu Ohtsuka
Affiliation:
Fisheries Laboratory, Hiroshima University, Takehara, Japan
*
Corresponding author: Shinta Fujimoto; Email: shinta.f@water-bears.com
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Abstract

Marine tardigrades are known from all oceans. However, Euclavarctinae (Halechiniscidae) is the only family-group taxon exclusive to the deep sea. We describe a new genus and species of this taxon, Ranarctus kondoi gen. et sp. nov. The new genus and species was sorted from a sediment sample collected at a locality north of Kuroshima island, Kerama Islands, Okinawa, Japan (water depth: 596–606 m) during a T/RV Toyoshiomaru cruise (Hiroshima University) in 2003. It does not completely conform to the subfamily’s diagnosis as in the case of Parmursa by its aliform expansions, trapezoid head, and primary clava and lateral cirrus sharing a common pedestal. Aside from these similarities, Ranarctus gen. nov. differs from Parmursa by its wrinkled aliform expansions lacking ribs, cephalic cirri’s constant-width scapi, and internal digits longer than external ones.

ZooBank LSID: urn:lsid:zoobank.org:pub:F096F6D5-0A25-4E99-8258-767550931186.

Keywords

East China SeameiofaunaPacific OceanSEMtaxonomy

Information

Type
Research Article
Information
Journal of the Marine Biological Association of the United Kingdom , Volume 106 , 2026 , e24
Copyright
© The Author(s), 2026. Published by Cambridge University Press on behalf of Marine Biological Association of the United Kingdom.

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