Phylum: Mollusca
Class: Gastropoda
Order: Euomphalina
Family: Holopeidae Wenz, 1938
Cincinnatian Genera: Cyclora, Holopea

Geologic Range
Late Ordovician – Middle Permian

Common Paleoecology
Holopeidae is an extinct family of stationary epifaunal suspension feeders

Description of the Family

  • U-shaped sinus
  • Turbiniform
  • With or without spiral ornament
  • Narrow umbilicus

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Popov et al. (2007):

  • Wagner (2002) emphasized a primitively expressed U-shaped sinus and simple growth lines for his “Holopeines” subclade within a “Raphistomatid” clade (informal notation, as indicated by quotes; see Wagner 2002; 16). Traditionally, a number of Paleozoic anisostrophically coiled gastropods showing these characters would be classified within the Late Cambrian to Early Ordovician Sinuopeidae Wenz, 1938. Many of these genera are now placed in the family Holopeidae Wenz, 1938 (e.g., Raphistomina Ulrich and Scofield 1897; Pachystrophia Perner, 1903; Sinutropis Perner, 1903; Umbospira Perner, 1903; Holopea Hall, 1847), and all are younger than the late Arenigian (Wagner 2002). The genus discussed here, Ptychonema Perner, 1903, is placed in Holopeidae by association with morphologically similar mid-Ordovician to Silurian genera with a U-shaped sinus; Horny (1997) placed it in Eotomariidae Wenz, 1938.

Treatise on Invertebrate Paleontology, Part I, Mollusca 1 (1960):

  • Turbiniform, with or without spiral ornament; usually with narrow umbilicus.

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