Isorophus cincinnatiensis

Species: Isorophus cincinnatiensis (Roemer, 1851)

Taxonomic Details

Formerly: Agelacrinus cincinnatiensis, Agelacrinites cincinnatiensis, Carneyella cincinnatiensis, Lepidodiscus cincinnatiensis
Includes: Agelacrinus holbrooki, Isorphus holbrooki, Carneyella holbrooki

Stratigraphic Occurrences

I. cincinnatiensis_strat

Geographic Occurrences

Map point data provided by iDigBio.

Stratigraphic Description

Sequences (Formations)

  • C5 Sequence (Lower Whitewater)
  • C4 Sequence (Arnheim)
  • C3 Sequence (Corryville)
  • C2 Sequence (Bellevue)

Identification in Hand Sample

  • Moderate to large domed theca
  • Smaller secondary ambulacral cover plates
  • Long, curved ambulacra
  • May exceed 2.5 cm in diameter
  • Double biseries of plates along the ambulacra and 4 primary oral plates

Isorophus cincinnatiensis from unknown formation of Hamilton County, Ohio (OUIP teaching collection)

Published Description

Holland (UGA Strat Lab, 2013):

  • Moderate to large domal theca, with relatively smaller secondary ambulacral cover plates

Davis (1998):

  • Edrioasteroid. Characterized by numerous plates and long, curved ambulacra. May exceed 2 ½ cm (1”) in diameter. Fairmount up to Mount Auburn.

Fossils of Ohio (1996):

  • Can be distinguished by having double biseries of plates along the ambulacra and four primary oral plates.

Bell (1974):

  • Moderate to large diameter; five or more secondary orals; primary ambulacral coverplates distinctly larger externally than secondaries; secondaries rarely reaching adradial suture line externally; interambulacrals proportionately of moderate size.