Cincinnetina multisecta

Classification
Phylum: Brachiopoda
Class: Rhynchonellata
Order: Orthida
Family: Dalmanellidae
Genus: Cincinnetina
Species: Cincinnetina multisecta (Meek, 1873)

Taxonomic Details

Formerly named: Onniella multisecta, Dalmanella multisecta

Stratigraphic Occurrences

multisectastrat

Geographic Occurrences

Map point data provided by iDigBio.

Stratigraphic Distribution

  • C2 sequence (Fairview: Fairmount, Mount Hope)
  • C1 sequence (Clays Ferry/Kope: McMicken, Southgate, Economy/Fulton)

Identification in Hand Sample
Cincinnetina multisecta is a Late Ordovician brachiopod that is characteristically small and rounded. The ventral (pedicle) valve is convex than the dorsal (brachial) valve, which is nearly flat. The hinge line is distinctly shorter than the width of the shell. In proposing the combination Cincinnetina multisecta, (Jin, 2011) cited a consistently developed primary medial costa (shell ridges) in the dorsal valve, and a larger, three lobed cardinal process, which is where the abductor muscles would have attached.

  • Dorsal valve flattened, exhibits a shallow sulcus
  • Triangular pedicle opening
  • Hinge line distinctly shorter than greatest width of shell

Cincinnetina multisecta from Fairview formation of Campbell County, Kentucky (OUIP 404)

Published Descriptions

Jin (2011) :

  • The most common forms of Late Ordovician dalmanellid brachiopods from the Cincinnatian type area, previously treated as either Dalmanella or Onniella, are assigned to Cincinnetina gen. nov. 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 Globally, Dalmanella and Onniella occur most commonly in deposits of relatively deep- or cool-water palaeoecological settings, whereas in North America, Cincinnetina, Paucicrura and Diceromyonia are found mainly in carbonate- rich deposits in warm-water depositional environments, with Cincinnetina and Paucicrura most common in pericratonic settings and Diceromyonia in palaeoequatorial inland seas.

Davis (1998):

  • (O. multisecta) Articulate brachiopod- compare with emacerata; triangular pedicle opening; brachial valve – note double cardinal process – Economy through Fairmount

McFarlan (1931):

  • Dalmanella multisecta: A relatively small, rounded, and more coarsely striated species than the above. Pedicle valve quite convex, rounded or centrally ridged, brachial valve flattened, and in the more robust forms with a well developed median sinus. Hinge line distinctly shorter than greatest width of shell. Commonly 10-12 striae in 5 mm. along the anterior margin. Width 12-15 mm., length 0.8-0.85 width.