Ophioplax Lyman, 1875

Stöhr, Sabine, 2024, Taxonomic analysis of the genital plates and associated structures in Ophiuroidea (Echinodermata), European Journal of Taxonomy 933, pp. 1-98 : 52-54

Genus Ophioplax Lyman, 1875

Fig. 24D–J

Type species

Ophioplax ljungmani Lyman, 1875 .

Examined species

Ophioplax lamellosa Matsumoto, 1915 .

Oral GP

Not examined, in situ obscured by granules, but laterally at oral shield a large scale discernible at either side, considered as oral GP.

Adradial GP

Proximal half bar-like, distally weakly cleaver-shaped with wide dorsal and ventral processes; rounded distal part offset from proximal bar by a kink. Articular structure a prominent round distal condyle, bordered by a deep groove and wide edge. Proximal to condyle on dorsal side of offset part a large patch of finer meshed stereom.

Abradial GP

Sabre-shaped, flat, thin, ventral edge convex, dorsal edge slightly concave, long concave distal articular structure.

Oral shields

Flat, on distal part a weak spur on each side, offsetting distal lobe from proximal part. Madreporite inner side inflated in middle, two lateral distal spurs, flat proximal margins, large opening in distal lobe.

Radial shield

Low distal condyle near adradial edge, distally bordered by short groove. Proximal to condyle a large oval patch of finer stereom.

Figures

Fig. 24. Ophionereididae Ljungman, 1867, SEM, unless otherwise noted. A–C. Ophiochiton fastigatus Lyman, 1878. A. Ventral disc section, digital photo. B. adGP, proximal end broken. C. abGP. D–J. Ophioplax lamellosa Matsumoto, 1915. D. Ventral interradius. E. adGP, lateral aspect (adradial?). F. abGP. G. adGP, dorsal aspect. H. Radial shield, inner aspect. I. Madreporite, inner aspect. J. Oral shield, inner aspect. Scale bars: 0.5 mm.