Taxonomic analysis of the genital plates and associated structures in Ophiuroidea (Echinodermata) Author Stöhr, Sabine 412800EB-AACE-4313-9810-61F89B740405 Swedish Museum of Natural History, Department of Zoology, Box 50007, 10405 Stockholm, Sweden. sabine.stohr@nrm.se text European Journal of Taxonomy 2024 2024-05-14 933 1 98 https://europeanjournaloftaxonomy.eu/index.php/ejt/article/download/2525/11335 journal article 10.5852/ejt.2024.933.2525 2118-9773 11198874 8F720F2B-BFBC-4CA1-BFF2-A2B8C7C8D3E1 Genus Ophienigma Stöhr & Segonzac, 2005 Fig. 32F–I Type species Ophienigma spinilimbatum Stöhr & Segonzac, 2005 . Examined species Ophienigma spinilimbatum . Oral GP Not examined. Adradial GP Wrench-shaped adradio-dorsal distal end (condyle separated from process by deep incision), single condyle bordered by shallow groove. Abradial GP Sickle-shaped, flat, distally with concave articular structure, almost as long as adGP. Oral shields Madreporite with large centrodistal opening. Radial shield Single condyle and shallow groove. Patch of finer meshed stereom proximal to condyle. Remarks The genital plates and madreporites of Ophienigma spinilimbatum and Ophiopus arcticus show great similarity, which suggests that they are most likely closely related. The wrench shape of the adradial GP is also shared with Ophiactis .