Phylum: Mollusca
Class: Gastropoda
Order: Euomphalina
Family: Holopeidae
Genus: Cyclora Hall, 1845
Cincinnatian Species: Cyclora depressa

Taxonomic Details

Synonyms: Cyclonema Knight, 1941 & Knight et al., 1960

Geologic Range
Late Ordovician

Common Paleoecology
Cyclora is an extinct genus of stationary epifaunal suspension feeders

Identification in Hand Sample:

  • Minute umbilicus
  • Circular aperture
  • Smooth columella
  • Thin, subglobular shell
  • Short spire
  • Few whorls

Geographic Occurrences

[leaflet-map lat=39 lng=-84.5 zoom=7 width=575 height=250 align="right"]
Map point data provided by iDigBio.

Published Description

Holland (UGA Strat Lab, 2013):

  • Cyclora may be a junior synonym of Cyclonema as it may be the juvenile part of the shell

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

  • Very minute, naticiform. [Probably based on steinkerns of protoconchs of some other genus, possibly Cyclonema; Locally very abundant]

Miller (1874) :

  • Shell minute, smooth, consisting of few whorls; aperture circular. Prof. Meek suggests that this genus probably belongs to the family Rissoidae.

Hall (1845) :

  • Subglobose, shell thin, spire short, consisting of a few whorls; columella smooth, slightly reflected over a minute umbilicus, aperture circular.