†Onychochilidae is an extinct family of small, fossil, upper Cambrian to lower Devonian molluscs.
They have hyperstrophically coiled shells which generally have smooth whorls and elongate apertures.
Robert M. Linsely and William M. Kier, 1984 [2] reassigned the Onychochilidea to the Paragastropoda, a new class of molluscs proposed for gastropod-like forms which they interpreted as being untorted - that is viscerally not twisted.
The Onychochilidae was at that time placed in the Onychochilacea, a superfamily included in a new order, the Hyperstophina, named for paragastropods with hyperstrophic to depressed-orthstrophic shells.
Bouchet and Rocroi, 2005 [3] tentatively retained the Onychochilidae in the Gastropoda, including them along with the Clisospiridae in the superfamily Clisospiroidea, and added a third subfamily, the Hyperstropheminae, named for Hyperstrophema Horney, 1964, its sole known genus.