Order Ophioleucida O’Hara et al., 2017

Diagnosis

Dorsal disc with granules. Radial shields with distal adradial portion exposed. Abradial genital plate with concave adradio-distal tip. Dorsal arm plates rectangular to trapezoid with straight edges. Arm spine articulations irregularly rhombic, framing large, dorsoventrally elongated muscle opening, small nerve opening ventral to articulation. Lateral arm plates fragile. Arm spine articulations commonly separated from distal plate edge by a ledge. Ventro-distal edge of lateral arm plates protruding ventralwards.