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 Gorgonocephalus Leach, 1815 Fig. 7 Type species Asterias caputmedusae Linnaeus, 1758 . Examined species Gorgonocephalus caputmedusae . Oral GP Absent. Fig. 7. Gorgonocephalidae Ljungman, 1867 , Gorgonocephalus caputmedusae (Linnaeus, 1758) , SEM images (except A, D, digital images). A . Dorsal disc inner side with radial shields exposed. B . Radial shield distal end, ventrolateral view. C . Radial shield, distal end, ventral view. D . adGP in situ. E–G . adGP, distal end fragments. H . adGP proximal part fragment. I . Madreporite, inner aspect. Scale bars: 1 mm . Adradial GP Long with bulbous distal end, extending in an L-shape or as a rounded structure fused to abGP; parallel to arm vertebrae, as long as at least nine segments. Distal edge large and flat, no special articular structures, a depression in dorsal surface. Proximal part with deep median furrow, in cross section u-shaped. Fragmented into multiple, different sized pieces during bleaching. Abradial GP Small, attaching under proximal edge of bulbous L-shaped part on adradial GP or both fused to form a single structure. Oral shields Regular OS absent, but one or several madreporites, thickened, externally with numerous scattered small pores (transverse row of 7–8 pores in G . lamarcki (Müller & Troschel, 1842) , inner side a meshwork of irregular lamellae and openings. Radial shield Long, bar-like with widened distal end, ventral side with flat, smooth articular patch at distalmost end, proximal to widened part a concave patch. Dorsal surface wider than ventral bar, creating thin lateral overhanging edges, with scaly appearance and numerous pores where disc granules were attached. Fragmented into several different sized pieces during bleaching. Remarks Radial shields and genital plates broke easily during bleaching in Gorgonocephalus .