Tentaculites richmondensis

Classification
Phylum: Mollusca
Class: Tentaculida
Family: Tentaculitidae
Genus: Tentaculites
Species: Tentaculites richmondensis (Miller, 1874)

Stratigraphic Occurrences

T.richmondensis_strat

Geographic Occurrences

		
Map point data provided by iDigBio.

Stratigraphic Description

Sequences (Formations)

  • C5 Sequence (Whitewater)

Identification in Hand Sample

  • 25-30 mm in length
  • Widely spaced rings (20-30 of them on adults)
  • About 40 longitudinal thin ribs (lirae) on shell, only visible in well preserved specimens.
  • Straight shell form
  • The proximal portion of the conch has a few septa, but these can only be seen in thin sections
Tentaculites_richmondensis_800px

Tentaculites richmondensis from Waynesville formation of Warren County, Ohio (OUIP 1785, left) and from Liberty formation of Franklin county, Indiana (OUIP 2234, center and right)

Published Description

Holland (UGA Strat Lab, 2013):

  • typically large (25-30mm long, 2-3 mm wide at aperature), with widely spaced rings (20-30 on adult)

Davis (1998):

  • Cricoconarid mollusk. Straight, conical shell with bold transverse ridges. Waynesville through Whitewater.

Fossils of Ohio (1996):

  • The conch of Tentaculites richmondensis is straight or slightly curved, 25-30 mm long, and 2-3mm wide at the aperture. The rings on the surface of the conch are quite distinct, essentially symmetrical, and have rather sharp crests. Adjacent rings are of rather uniform size, although there is a gradual increase in ring size from the proximal end to the distal end. There are 20-30 rings in an adult specimen and there are no annulets. Ornamentation on the conch surface includes about 40 longitudinal thin ribs (lirae), but these are clearly visible only in well preserved specimens. The proximal portion of the conch has a few septa, but these can only be seen in thin sections. This species occurs in the Waynesville through Whitewater formations. It’s is quite common locally, and dozens of specimens may be found together on a bedding plane.

Miller (1874):

  • Tube free or detached, straight, conical, gradually tapering from the aperture to the obtuse point. Surface marked by strong encircling annulations or constrictions, which are crossed be very fine, regular, longitudinal striae.
  • Length of specimen about one inch; diameter at the aperture about 1 ¼ lines; width of the annulations at the aperture about half line, which gradually diminish to less than one-quarter that size, and become nearly obsolete as they approach the closed end of the tube.
  • While some of the tubes appear to be slightly curved toward the point, yet the numbers observed, which are broken across each other and across coral stems and other inequalities of the surface with which they came in contact, indicate that the tubes were very slightly, if at all, flexuous.
  • The tubes have a marked resemblance to Conchicolites flexuosa (Hall), though they may be readily distinguished by their much larger size, straight instead of curved form and free instead of attached habit.