Gaurocrinus

Classification
Phylum: Echinodermata
Class: Crinoidea
Order: Diplobathrida
Family: Reteocrinidae
Genus: Gaurocrinus Miller, 1883
Cincinnatian Species: Gaurocrinus nealli

Geologic Range
Late Ordovician

Common Paleoecology
Gaurocrinus is an extinct genus of stationary upper-level epifaunal suspension feeders

Identification in Hand Sample:

  • Column round or pentagonal, and composed of thinner and thicker plates
  • Calyx having strong radial ridges, and depressed interradial and intersecondary radial areas
  • Azygous area supported by a ridge up the middle series of plates
  • Arms, twenty or more, possessing pinnules
  • Stem pentagonal transversely

Geographic Occurrences

Published Description

Fossils of Ohio (1996):

  • Camerate with uniserial brachials.

Broadhead (1987):

  • Gaurocrinus, incorrectly assigned to the Reteocrinidae in the Treatise, is characterized by pinnulate arms and only two IBrr per ray

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

  • Similar to Reteocrinus, but with interbrachials very irregular in form and size. Arms branching isotomously once or twice at rather long intervals; 2 to 3 fixed pinnules on each arm, 1st one considerably stouter than others; free brachials very short, wedge-shaped, pinnulate. Stem pentagonal transversely.

Miller (1883):

  • This genus is established to receive those species heretofore referred to Glyptocrinus, but which have basal and subradial plates. It may be defined as follows :Column round or pentagonal, and composed of thinner and thicker plates. Calyx having strong radial ridges, and depressed interradial and intersecondary radial areas. Basals, five, presenting a low triangular face on the uxterior, or having slightly truncated lateral angles. Subradials, five, heptagonal, height and width subequal. Primary radials, three by five, or as in the type, the left posterior ray may have only two. Secondary radials, ten to sixteen by ten. Interradial and intersecondary radial areas covered by numerous small plates. Azygous area supported by a ridge up the middle series of plates, gradually becoming obsolete as it approaches the vault. Vault, covered by numerous small plates, which are continued as a covering over the ambulacral furrows. Arms, twenty or more, possessing pinnules. Type, Gaurocrinus nealli, which will be particularly defined.”

G. nealli