Cincinnetina

Classification
Phylum: Brachiopoda
Class: Rhynchonellata
Order: Orthida
Family: Dalmanellidae
Genus: Cincinnetina Jin, 2011
Cincinnatian Species: Cincinnetina meeki, Cincinnetina multisecta

Taxonomic Details

Cincinnetina species were previously placed within the genera: Onniella, Dalmanella

Geologic Range
Late Ordovician

Common Paleoecology
Cincinnetina is an extinct genus of stationary, epifaunal suspension feeders

Characteristics of Genus

  • The North American descendent of Dalmanella
  • Ventribiconvex (the two valves are both convex, but the “top” valve with the beak is more convex
  • Multicostellate to weakly fasciocostellate
  • In the dorsal valve there is a well defined central costella (line)
  • Under microscope, distinctive fine and course punctae visible
  • Commonly confused with Dalmanella, but Cincinnetina is the genus found in the North America

Geographic Occurrences

Published Description

Jin (2011):

  • Shell subcircular, ventribiconvex in adults; multicostellate to weakly fascicostellate, with medial line of dorsal valve marked by interspace. Punctae differentiated into two sizes; aditicules absent. Dental plates divergent posteriorly, becoming subparallel anteriorly to serve as lateral bounding ridges of small, cordate muscle field. Cardinal process delicate, with bilobate myophore; brachiophore plates inclined baso-medially; fulcral plates normally present (emended Jin and Bergstrom 2010)
  • Differs from Dalmanella and Onniella in having a consistently developed primary medial costa in the dorsal valve, a larger cardinal process that tends to develop a trilobed myophore, strongly differentiated fine and coarse punctae, and sparse aditicules. Cincinnetina can be distinguished from the closely related Paucicrura and Diceromyonia in its smaller trilobed cardinal process (when developed) that does not have a dominant medial lobe and does not extend into the delthyrial cavity of the ventral valve.
  • Former Species Names: Dalmanella meeki, Dalmanella multisecta, Onniella meeki, Onniella multisecta

Fossils of Ohio (1996):

  • Dalmanella Hall & Clarke is a small to medium sized orthid brachiopod. It has a gently biconvex profile, and the oval to subcircular profile is truncated by a straight hinge line. Width is greater than length, although it may only be just so. The brachial valve has a shallow sulcus. Ribs radiate from the beaks towards the commissure. The ribbing may be finer than that of Plaesionmys and Glyptorthis and certainly finer than that of Plectorthis. Species of Dalmanella have been referred to Onniella by some workers (example: Walker, 1982). Dalmanella has been recorded from much of the Cincinnatian series.

C. meeki


C. multisecta