Ophiochiton Lyman, 1878

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

Genus Ophiochiton Lyman, 1878

Fig. 24A–C

Type species

Ophiochiton fastigatus Lyman, 1878 .

Examined species

Ophiochiton fastigatus .

Oral GP

Externally visible as large, round scales, but not examined.

Adradial GP

Weakly cleaver-shaped, flat, blade-like proximal part, distal end depressed with high edges, a large rough patch on adradial surface towards dorsal edge, and a large hole in middle of distal part on adradial surface.

Abradial GP

Hockey-stick-shaped, blade-like, flat, as long as adGP, distal end angled, pointed, distal dorso-adradial edge with depression. Lines abradial edge of genital slit (= part of edge of interradial disc).

Oral shields

Not examined.

Radial shield

Not examined.

Remarks

The available pre-existing images allow only limited assessment of the articular structures of the adradial GP. Martynov (2010) described them as a condyle bordered by a low ridge but without figures, whereas Matsumoto (1917) wrote that the radial shield and adradial GP articulate with two condyles and one pit. The images presented here appear to be the first published SEM images of genital plates of Ophiochiton .

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.