Hadal Mud Dragons: First Insight Into the Diversity of Kinorhyncha From the Atacama Trench

Katarzyna Grzelak*, Daniela Zeppilli, Mauricio Shimabukuro, Martin V. Sørensen


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Deep-sea trenches are one of the last frontiers for deep-sea exploration and represent a large reservoir of undiscovered biodiversity. This applies in particular to organisms belonging to smaller-size classes, such as meiofauna. Among different meiofauna taxa, kinorhynchs represent a large gap in our knowledge about global marine biodiversity in general, but primarily in extreme deep-sea environments. Out of the more than 300 known mud dragon species, only a single species has ever been described from hadal depths (> 6000 m), i.e., Echinoderes ultraabyssalis from the Kuril-Kamchatka Trench. The results presented in this paper are based on material collected during a research expedition in 2018 investigating the Atacama Trench environment. We provide a first overview and comparison of the diversity and abundance of mud dragons in the Atacama Trench, the adjacent abyssal plain and continental slope off Chile. The study revealed six species of Echinoderes. Of these, Echinoderes mamaqucha sp. nov. is described as a new species and morphological data of three undescribed species are given. Because of the low number of available specimens, we provide only a brief description of these three species and comparison with their morphologically closest congeners, but formal descriptions are not given. Moreover, Echinoderes juliae and Echinoderes pterus were also recovered. Echinoderes juliae was described from the abyssal plain off Oregon and along the continental rise off California, at 2702 to 3679 m depth. Echinoderes pterus is known from the high Arctic, the North Atlantic, and the Mediterranean Sea, and has also been reported to show a wide bathymetric distribution, from 675 to 4403 m. Interestingly, E. mamaqucha sp. nov. dominated at the trench stations and it reached its highest abundance at the deepest station, at 8085 m water depth. The only other single individual that was found in the Atacama Trench was Echinoderes sp.1. The remaining four species were all found at the abyssal and slope stations. The obtained results seem to confirm previous hypotheses about geographic isolation of deep-sea trenches and relatively low connectivity with other habitats, reflected by limited diversity of sediment dwelling fauna, particularly in the deepest parts of trenches.

TidsskriftFrontiers in Marine Science
Antal sider22
StatusUdgivet - jun. 2021

Bibliografisk note

Funding Information:
We are indebted to Ronnie Glud (SDU) for the invitation to work on Atacama meiofauna. Special thanks go to the chief scientists (Ronnie Glud/SDU, Frank Wenzh fer/AWI, and Matthias Zabel/MARUM), captain, and crews of the cruise SO261 (R/V SONNE, 02/03-02/04/18). We thank Sophie Arnaud and Miriam Brandt for support during sampling activities. We would also like to thank Nuria S?nchez (Ifremer/UCM) for help in preparation of animals, Nicolas Gayet (Ifremer) for help in the SEM preparation, Eve Julie Pernet (Ifremer) for support in the laboratory, and Emilia Trudnowska (IOPAN) for help with map preparation. This article is registered at www.zoobank.org under urn:lsid:zoobank.org:pub:1A9867FF-1C58-F17-A869-F7534B262518. Funding. This study was funded by the project ?Prokaryote-nematode Interaction in marine extreme envirONments: a uniquE source for ExploRation of innovative biomedical applications? (PIONEER) funded by the Total Foundation and IFREMER (2016?2019). Financial support was also provided through the European Research Council (HADES-ERC Project Grant No. 669947) and by the Danish National Research Foundation (Grant No: DNRF145, Danish Center for Hadal Research, HADAL). The first author was supported by the Polish National Agency for Academic Exchange NAWA, the Bekker Programme Fellowship (PPN/BEK/2019/1/00160/00001) at Natural History Museum of Denmark and partly by the statutory funds from the Institute of Oceanology, Polish Academy of Sciences (IO PAN).

Publisher Copyright:
© Copyright © 2021 Grzelak, Zeppilli, Shimabukuro and Sørensen.


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