Phylum: Mollusca
Class: Gastropoda
Order: Murchisoniina
Family: Trochonematidae (von Zittel, 1895)
Cincinnatian Genera: Trochonema

Geologic Range
Middle Ordovician – Middle Permian

Common Paleoecology
Trochonematidae is an extinct family of facultatively mobile epifaunal suspension feeders

Description of the Family

  • Turbiniform shell
  • Perforate or imperforate
  • Surface of shell exhibits several strong revolving ridges or numerous spiral striae
  • Shell has nacreous lining
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Treatise on Invertebrate Paleontology, Part I (1960) (Same as Superfamily Trochonematacea):

  • Turbiniform, with channel at labrum within a spiral angulation about midway between sutures or higher on whorl, or with shallow sinus at about the same position; ornament spiral angulations, threads or cords, or rows of nodes, with collabral threads or growth lines; shell with nacreous lining.

Ulrich & Scofield (1897):

  • Shells trochoid, turbiniform or somewhat planorbiform, perforate or imperforate; margin of aperture entire, simple, rarely trumpet-shaped, sometimes with a wide angled notch and carina in the upper or outer part; no slit nor distinguishable band; surface with several strong revolving ridges or more numerous spiral striae; test very slightly or not at all nacreous. Operculum unknown, probably incapable of preservation.

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