Ophiotypa Koehler, 1897

Stöhr, Sabine, 2024, Taxonomic analysis of the genital plates and associated structures in Ophiuroidea (Echinodermata), European Journal of Taxonomy 933, pp. 1-98 : 47

Genus Ophiotypa Koehler, 1897

Fig. 21M–P

Type species

Ophiotypa simplex Koehler, 1897 .

Examined species

Ophiotypa simplex .

Oral GP

Absent.

Adradial GP

Cup-shaped convex, smaller than lateral arm plate to which it attaches. Articular structure a flat distal surface.

Abradial GP

Absent.

Oral shields

Not examined.

Radial shield

Single large plate above each arm base with two flat articular structures separated by a depression.

Remarks

Ophiotypa simplex is the only species in its genus and strongly paedomorphic. Its disc consists of few large plates. Pairs of radial shields appear to have been fused into a single large plate or are replaced by the radial primary plates functioning as radial shields, but individuals with a pair of plates on one or several radii have been observed (unpublished data, Stöhr & Martynov). The ventral disc is covered by the large oral shield, genital slits are not visible and the abGP appears to be absent.

Figures

Fig. 21. Ophiolepididae Ljungman, 1867, SEM, unless otherwise noted. A–L. Ophiolepis variegata Lütken, 1856. A. Oral disc, digital image. B. Genital plates at arm. C. adGP, abradial aspect. D. adGP, adradial aspect. E. Radial shield and abGP at arm. F. abGP and adGP articulated. G. abGP, inner aspect. H. Oral shield, inner aspect. I. Madreporite, inner aspect. J–K. Oral GP, uncertain aspects. L. Radial shield, inner aspect.M–P. Ophiotypa simplex Koehler, 1897.M. adGP articulated at arm and under fused radial shields (or radial primary plates). N. oGP, inner aspect. O. oGP, outer aspect. P. Radial shields (or radial primary plates), inner aspect. Scale bars: A–G, L–M, P=1 mm; H–K=0.5 mm; N–O =0.2 mm.