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 Euryale Lamarck, 1816 Fig. 9 Type species Euryale aspera Lamarck, 1816 . Examined species Euryale aspera . Oral GP Absent. Adradial GP Bar-like, distally thickened, curving upwards, flat articular structure and shallow groove. Abradial GP Isosceles triangular, thick, distal end straight, proximal end pointed, attaches along proximal dorsal edge of adGP. Fig. 9. Euryalidae Gray, 1840 , Euryale aspera Lamarck, 1816 . A, G= digital images; B–F, H–J =SEM images. A . adGP in situ. B . adGP abradial view. C . adGP, dorso-adradial view. D . Radial shield, dorsal view. E . Radial shield, latero-ventral view. F . abGP. G . Section of ventral disc. H . Adoral shields and madreporite, inner view. I . Madreporite, inner aspect. J . Other madreporite, inner aspect. Scale bars: A–H=1 mm; I–J =0.5 mm Oral shields All madreporic.At size 22 mm dd, minute, externally one or two pores visible. Internally, one madreporite elongated (slipper-shaped), proximally rounded and closed over, in middle a square opening, distal part narrower, tube-like closed, distal end open. Another madreporite internally not closed over, with deep openings and several septa. Only distal surface externally visible at vertical interradius, madreporite placed on inner side of two adradial shields, completely covered. Radial shield Bar-like, curved, distal end in dorsal aspect spatulate, widened, in ventral aspect rounded, gradually increasing in thickness from proximal to distal, articular structures as two flat patches, one on ventral side, one as distal surface. Proximal to articular structures a concave part with several holes.