Family Ophiohelidae Perrier, 1893

Ophiomycetidae Verrill, 1899b: 359 (see Thuy & Meyer 2013; Parameswaran et al. 2016).

Type genus

Ophiohelus Lyman, 1880 (type species: O. umbella Lyman, 1880).

Other genera

Ophiomyces Lyman, 1869, Ophiothauma H.L. Clark, 1938, Ophiotholia Lyman, 1880 .

Diagnosis

Disc fully scaled but radial shields absent, giving the disc a sac-like shape. Jaws (oral plates) covered by numerous flat papillae, except in Ophiothauma . Large flat teeth. Arm spine articulations separated from distal edge by a fragile ledge with a distalwards pointing ventral extension. Articulation with nearly vertical dorsal and ventral lobes, connected at their proximal ends, opening into a wide y- or horseshoeshape, bordering a single muscle/nerve opening, dorsal lobe larger and bent. Lateral arm plates generally with irregular, smooth vertical striation. Conspicuous parasol-shaped arm spines in Ophiohelus and Ophiotholia . Ventral arm plates often with sockets for tentacle scales.