Family Ophioscolecidae Lütken, 1869 (emended, paraphyletic assemblage, see Fig. 2)

Type genus

Ophioscolex Müller & Troschel, 1842 (type species: O. glacialis Müller & Troschel, 1842).

Other genera

Ophiocymbium Lyman, 1880, Ophiogeron Lyman, 1878a, Ophiohyalus Matsumoto, 1915, Ophiohymen H.L. Clark, 1911, Ophioleptoplax H.L. Clark, 1911, Ophiologimus H.L. Clark, 1911, Ophiolycus Mortensen, 1933 a, Ophiophrura H.L. Clark, 1911, Ophioplexa Martynov, 2010, Ophioprium H.L. Clark, 1915a, Ophiorupta Martynov, 2010, Ophiosyzygus H.L. Clark, 1911, Ophiuroconis Matsumoto, 1915 .

Diagnosis

Dorsal disc and arms with thickened skin, thin glassy disc scales, reduced in number or absent in some genera ( Ophioscolex), mostly naked but scattered smooth disc spines or dense granules occur in some species. Spiniform teeth, forming apical clusters in some genera, spiniform oral papillae. Paired ventralmost teeth, dental plate entire, round sockets, not penetrating. Arm spine articulations adjacent to distal edge of lateral plate, as single opening for both muscle and nerve, with a horseshoe-shaped border in some genera ( Ophioscolex, Ophiogeron), as separate nerve and muscle openings bordered by a larger dorsal and smaller ventral lobe in others ( Ophiolycus).