Ophiozonella Matsumoto, 1915

Stöhr, Sabine, 2024, Taxonomic analysis of the genital plates and associated structures in Ophiuroidea (Echinodermata), European Journal of Taxonomy 933, pp. 1-98 : 44-45

Genus Ophiozonella Matsumoto, 1915

Fig. 20

Type species

Ophiozona longispina H.L. Clark, 1908 .

Examined species

Ophiozonella longispina .

Oral GP

Not examined in detail. Genital slit lined by narrow elongated plates connecting to OS laterodistally, pair widely separated, similar to condition in Ophiolepis .

Adradial GP

Comma-shaped, distally wide and thick, proximally tapered to a point, ventral edge convex, dorsal edge concave and with a rough protrusion. Articular structures a distal depression, a condylar process with flat distal surface, bordered by a groove, proximally to this a large round to heart-shaped patch of finer stereom.

Abradial GP

As long as adGP, scoop-shaped with smooth, concave dorso-distal articular structure, accounting for a third to half plate length.

Oral shields

Inner side flat, no remarkable structures. Madreporite inner side with thickened proximal part with large central hole, opening into two proximal small pores.

Radial shield

Articular structures consist of a distal condyle and depression on an embossed part, at distal edge bordered by a narrow ledge. Proximal to depression a round coarse patch.

Remarks

The type species of Hemieuryalidae , Hemieuryale pustulata von Martens, 1867 , has a short abradial GP with a wider distal half and proximal thinner stalk (Gondim et al. 2015), more or less comma-shaped. The articular structures consist of a shallow stereom depression and a curved distal groove, matching similar structures on the radial shield; the abradial GP was not found and may be absent (Gondim et al. 2015). The radial shield has similar articular structures as in O. longispina . Oral GPs were not known when that study was performed, but oral images of H. pustulata in Gondim et al. (2015) show that the short proximally positioned genital opening is abradially lined by a large flat scale that connects to the oral shield and this is likely an oral GP. In Sigsbeia murrhina Lyman, 1878 and S. lineata Lütken & Mortensen, 1899 , the genital slits are limited to small round openings near the oral shield ( Gondim de Farias 2016) and oral GP are considered absent.

Figures

Fig. 20. Hemieuryalidae Verrill, 1899. Ophiozonella longispina (H.L. Clark, 1908), SEM, unless otherwise noted. A. Section of ventral aspect, digital image. B. adGP, abradial aspect. C. adGP, adradaial aspect. D. adGP, dorsal aspect. E. abGP, dorsal aspect. F. Madreporite, inner aspect. G. Oral shield, inner aspect. H. Radial shield, inner aspect. Scale bars: 0.5 mm.