Phylum: Mollusca
Class: Bivalvia
Order: Modiomorphida
Family: Modiomorphidae
Genus: Corallidomus Whitfield, 1893
Cincinnatian Species: Corallidomus concentricus

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  • 1893 Corallidomus Whitfield, Geol. Surv. Ohio, Pal., 7, p. 493.
  • 1897 Corallidomus Miller, N. A. Geol. Pal., 2d App., p. 780.

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Geologic Range
Middle Ordovician – Late Ordovician

Common Paleoecology
Corallidomus is an extinct genus of stationary semi-infaunal suspension feeders

Identification in Hand Sample:

  • Oblong shell
  • Anterior and posterior muscle scars present
  • Integral pallial line
  • Radial ornamentation absent
  • Lacking teeth

Geographic Occurrences

Species Differentiation

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John C.W. Cope (2004) (from The Great Ordovician Biodiversification Event):

  • Two genera (Corallidomus and Semicorallidomus) developed the habit of excavating living space (crypts) within stromatoporoids or bryozoans. With the Hirnantian regression and exposure if the carbonate platforms, both genera became extinct, and with them died the habit of boring among bivalves, which was not to be re-evolved until the Late Jurassic.

Pojeta, Jr. & Runnegar (1985):

  • Various Ordovician modiomorphids such as Corallidomus have rugose comarginal ornament.
  • The lateral shape of Fordilla is readily compared with that of various Ordovician modiomorphid isofilibranchs such as Modiolodon, Corallidomus, and Modiolopsis.

Pojeta, Jr. (1971):

  • Boring infaunal pelecypods are not undoubtedly known in the Ordovician; however, Whitefield (1893 [1895]) described the boring modioliform modiomorphid Corallidomus and figured specimens of this genus embedded in burrows on the underside of a coral.
  • The probable boring clam Corallidomus is known only from Richmond Age rocks.
  • Corallidomus, the one probable Ordovician borer, looks much like a modioliform modiomorphid.

Treatise on Invertebrate Paleontology, Part N, Vol. 1 of 3 (1969):

  • Edentualous; without marked lateral sulcus or ventral sinus; radial ornamentation lacking

Whitfield (1893):

  • A bivalve mollusk having anterior and posterior muscular scars, and an integral pallial line; shell oblong, with an external ligament and somewhat modioliform outline, coupled with a burrowing habit of life. Type C. concentricus.

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C. concentricus