Superregnum: Eukaryota
Cladus: Unikonta
Cladus: Opisthokonta
Cladus: Holozoa
Regnum: Animalia
Subregnum: Eumetazoa
Cladus: Bilateria
Cladus: Nephrozoa
Cladus: Protostomia
Cladus: Spiralia
Cladus: Lophotrochozoa
Phylum: Mollusca
Classis: Gastropoda
Superfamilia Incertae sedis: † Clisospiroidea
Familia: † Onychochilidae
Genera (14): †Helicotis – †Hyperstrophema – †Invertospira – †Kobayashiella – †Laeogyra – †Matherella – †Matherellina – †Onychochilus – †Pelecyogyra – †Pervertina – †Scaevogyra – †Sinistracirsa – †Versispira – †Voskopiella
Name
† Onychochilidae Koken, 1925
References
Links
Onychochilidae in the World Register of Marine Species
†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. They are commonly considered to be gastropods, i.e. sea snails.
The Onychochilidae is included in the Macluritacea in the Treatise, Part I, 1960,[1] as part of the Archaeogastropoda where it is divided into two subfamilies, the Onychochilina for those with high basal spires, and the Scaevogyranae for those with low basal spires. 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.
References
Treatise on Invertebrate Paleontology, Part I, Mollusca 1. R.C. Moore (ed) Geol. Soc. of America and Univ. Kansas Press, 1960
Linsely, R. M. & W.M Kier, 1984. The Paragastropoda: a proposal for a new class of Paleozoic Mollusca. Malacologia, v.25, no1, pp 241-254
Bouchet, P. & Rocroi, J., 2005. Classification and Nomenclator of Gastropod Families Malacologia v.47. no 1-2.
Paleobiology database classification of the subfamilies and genera
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