Ophiosphalma monoplax (H. L. Clark, 1915)

Baker, Alan N., 2016, An illustrated catalogue of type specimens of the bathyal brittlestar genera Ophiomusium Lyman and Ophiosphalma H. L. Clark (Echinodermata: Ophiuroidea), Zootaxa 4097 (1), pp. 1-40 : 33

Ophiosphalma monoplax (H. L. Clark, 1915) .

Figures 55, a, b

Ophiomusium monoplax Clark, 1915 .

Ophiosphalma monoplax (Clark) ; H. L. Clark, 1941.

Paratypes (2) MCZ 509, off Dominica, 609m (the holotype was not found).

Main Features: Tumid disc plates with an open meshwork surface and deep sutures. Primary plates are surrounded by small plates. Radial shields joined at mid-length and there is a longer than wide interradial plate. Small, pointed oral shields, separated oral papillae. Three pairs of exposed tentacle pores, each with one large semioval scale. Pointed genital papillae run from adoral plates to arm bases. Up to five arm spines, uppermost hooked. Dorsal and ventral arm plates throughout arm. The two specimens measure 4 and 8 mm d.d.; there are more arm spines in the larger specimen. Clark’s holotype, at 12 mm d.d., had totally separated radial shields.