The Macluritoidea, or Macluritacea as it was originally spelled, is a superfamily of hyperstrophically coiled, Upper

Cambrian The Cambrian Period ( ; sometimes symbolized C with bar, Ꞓ) was the first geological period of the Paleozoic Era, and of the Phanerozoic Eon. The Cambrian lasted 53.4 million years from the end of the preceding Ediacaran Period 538.8 million ...

Devonian The Devonian ( ) is a geologic period and system of the Paleozoic era, spanning 60.3 million years from the end of the Silurian, million years ago (Mya), to the beginning of the Carboniferous, Mya. It is named after Devon, England, whe ...

archaeogastropods Archaeogastropoda (also known as Aspidobranchia) was a taxonomic order of sea snails used in older classifications of gastropods, i.e. snails and slugs. Archeogastropoda are marine prosobranch gastropod mollusks, mainly herbivores, typical ...

,Treatise on Invertebrate Paleontology, Part I, Mollusca 1. R.C. Moore (ed); Geol Soc of America and Univ Kansas Press, 1960 or paragastropods according to Linsely and Kier (1984).Robert M. Linsely, & Willian M. Kier, 1984. The Paragastropoda: a proposal for a new class of Paleozoic Mollusca. Malacologia, v.25, no.1, pp 241-254 Coiling is dextral, although it appears sinistral, deduced from the position of the channel (presumed to be exhalent) contained in a ridge or keel (a

selenizone A selenizone (from the Greek "selene" meaning "moon", and "zone" meaning "girdle") is an anatomical structure that exists in the shells of some families of living sea snails: the slit shells, the little slit shells and the abalones, which are m ...

on what is assumed to be the upper side. This is supported by the operculum of '' Maclurites'', which corresponds to that of dextral gastropods. According to the

Treatise A treatise is a formal and systematic written discourse on some subject, generally longer and treating it in greater depth than an essay, and more concerned with investigating or exposing the principles of the subject and its conclusions."Treat ...

the Macluritaceae includes two families, the Onychochilidae and Macluridae. Subsequent placement in the Paragastropoda is based on the assumption these animals were

untorted Torsion is a gastropod synapomorphy which occurs in all gastropods during larval development. Torsion is the rotation of the visceral mass, mantle, and shell 180˚ with respect to the head and foot of the gastropod. This rotation brings the mant ...

, that is they lacked the twisted viscera that are present in modern gastropods.

References

{{Taxonbar, from=Q6724707 Prehistoric gastropods