Phylum: Echinodermata
Class: Crinoidea
Order: Disparida
Family: Heterocrinidae
Genus: Cincinnaticrinus Warn & Strimple, 1977
Cincinnatian Species: Cincinnaticrinus pentagonus, Cincinnaticrinus varibrachialis

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Originally: Heterocrinus Hall 1847
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Geologic Range
Late Ordovician

Common Paleoecology
Cincinnaticrinus is an extinct genus of stationary intermediate-level epifaunal suspension feeders

Identification in Hand Sample:

  • Small and slender cup with basals long and upright
  • Somewhat irregular plates on pelvis
  • Arms slender, rounded, branching on primibrachs, 4 and with 2 or 3 higher equal divisions
  • Small anal X
  • Widely recognized in Late Ordovician of North America

Geographic Occurrences

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Fossils of Ohio (1996):

  • The genus Cincinnaticrinus is recognized throughout the late Ordovician in eastern North America. Cincinnaticrinus pentagonus and Cincinnaticrinus varibrachialas are the species of thus genus common in the Cincinnatian.

Treatise on Invertebrate Paleontology, Part T, Vol. 2 (1978):

  • (Under Heterocrinus)Cup small and slender; basals large and upright; C and E radials compound, others simple; anal X small, on upper left sloping shoulder of C superradial. Anal sac slender, armlike. Arms slender, rounded, branching on primibrachs, 4 and with 2 or 3 higher equal divisions. Column transversely pentagonal.

Warn & Strimple (1977):

  • Additionally major nomenclatural changes are needed because Heterocrinns heterodactylus (type species of Heterocrinus) is unrecognizable and the name must be restricted to Hall’s (1847) type
    specimens (from New York strata). Thus, new names must be given to taxa from strata in and around Cincinnati, Ohio, formerly attributed to Heterocrinus and H. heterodactylus (the authors choose
    the new names Cincinnaticrinus and C. varibrac hiatus for these taxa); and, because Heterocrinus is the type genus of the familial taxa Heterocrinidae and Heterocrinacea, new names must also be applied to these taxa (designated respectively, Cincinnaticrinidae and Cincinnaticrinacea herein).

Hall (Under Heterocrinus, 1847):

  • Column more or less pentagonal; pelvis composed of five plates which are somewhat irregular; costal plates in a single or partially double series, pentagonal, heptagonal or quadrangular; scapular plates regular; arms variable in character; fingers composed of a double or singles series of quadrangular joints, which are not tentaculated.
  • The two species which I have placed under this genus, have a similar pentagonal column, with the pelvic plates similar in each. The succeeding plates are somewhat irregular, but are few in number, and the entire structure very simple, interposed plates being entirely absent. Although I have but two species, and of these only imperfect specimens, it is evident they may with propriety constitute a distinct genus, on the basis of MILLERS arrangement.

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C. pentagonus

C. varibrachialus