Family Asteronychidae Verrill, 1899

Diagnosis. Arms simple, coiled. Disc five lobed or circular, covered with skin and/or plate-shaped external ossicles. Teeth spiniform, covering whole side of jaw. Radial shields narrow, multi-layered. Ventral arm plates limited to a few basal arm segments. Up to more than ten arm spines. Genital slits usually small, half the length of the height of the disc.