Beloitoceras cumingsi

Classification
Phylum: Mollusca
Class: Cephalopoda
Order: Oncocerida
Family: Oncoceratidae
Genus: Beloitoceras
Species: Beloitoceras cumingsi Flower, 1946

Stratigraphic Occurrences

Geographic Occurrences

Map point data provided by iDigBio.

Stratigraphic Description

Sequences (Formations)

  • C5 (Lower Whitewater)
  • C6 (Elkhorn, Upper Whitewater)

Identification in Hand Sample

  • Adorally compressed shells
  • Straight dorsum with convex venter
  • Sutures that slope from the dorsum to the venter
  • Smaller than B. amoenum with a more rapidly expanding shell

Beloitoceras cumingsi from Whitewater Formation of Oxford, Ohio (CMC 24414)

Published Description

Frey (1994):

  • Beloitoceras amoenum is most similar to B. cumingsi Flower, from equivalent fine-grained limestones of the Saluda Formation in southeastern Indiana and adjacent portions of western Ohio. Both species have adorally compressed shells that have their maximum diameter just adapical of the body chamber, straight dorsums, and sutures that slope adorally from the dorsum to the venter. Beloitoceras cumingsi differs from B. amoenum in being a smaller, more rapidly expanding shell.

Flower (1946):

  • This species, close in outline and aspect to Oncoceras, has a convex venter, as essentially straight dorsum, with the greatest shell height well below the base of the living chamber. The holotype, the least distorted specimen, increases from 20 mm. and 17 mm. at the base to a maximum height of 26 mm. and contracts slightly in the adoral 5 mm. of the phragmocone to a height of 27 mm. and a width of 22 mm. The dorsal length of the phragmocone is 16 mm., the ventral length 30 mm. The living chamber is 7 mm. long ventro-laterally and dorso-laterally, but is 7 mm. long on the venter owing to the development of a rather deep hyponomic sinus. The aperture has a height of 25 mm.
  • The paratype, apparently a thicken specimen, is actually different largely due to the compression of the shell. It increases from 18 mm. and 25 mm. in the ventral length of 40 mm. and a dorsal length of 20 mm. to 32 mm. and 23 mm. The living chamber is 11 mm. long laterally, and apparently 7 mm. long on the venter. The maximum height of the shell is 32 mm. The camerae of both specimens occur three in a length of 12 mm. adorally with little variation. The siphuncle is small and located close to the venter. The septa are relatively flat when exposed. The sutures develop only vestigial lateral lobes. The surface is not preserved.