Trematis millepunctata

Classification
Phylum: Brachiopoda
Class: Lingulata
Order: Lingulida
Family: Trematidae
Genus: Trematis
Species: Trematis millepunctata (Hall)

Stratigraphic Occurrences

T.millepunctata_strat

Geographic Occurrences

		
Map point data provided by iDigBio.

Stratigraphic Description

Sequences (Formations)

  • C6 sequence (Elkhorn, Whitewater)
  • C5 sequence (Whitewater, Liberty, Waynesville)
  • C4 sequence (Arnheim)
  • C3 sequence (Mount Auburn, Corryville)
  • C2 sequence (Bellevue, Fairview: Fairmount, Mount Hope)
  • C1 sequence (Clays Ferry/Kope: McMicken, Southgate, Economy/Fulton)

Identification in Hand Sample

  • Small to medium sized
  • Strongly convex ventral valve
  • Narrow and deeply depressed pedicle foramen
  • Pointed beak which projects beyond the cardinal margin of the ventral valve
  • Strongly punctate (in concentric curves passing from center outwards)
  • Internal layers of shell not punctate
  • Two large and semicircular to reniform muscle scars on dorsal valve
  • Center of dorsal valve has a slight mesial septum
Trematis_millepunctata_800px

Trematis millepunctata from Liberty formation of Franklin County, Indiana (OUIP 2178)

Published Description

Holland (UGA Strat Lab, 2013):

  • Circular to suboval shells covered in systematically arranged pits.

Davis (1998):

  • Inarticulate brachiopod. Low, convex pedicle valve, with lenticular pedicle opening. Brachial valve less convex than the pedicle valve; figure shows characteristic pitting which covers the shell.

Foerste (1924):

  • Shells approximately circular, with beak of brachial (dorsal) valve projecting moderately beyond circular outline. Pedicle valve with large, open fissure for emergence of pedicle. Valve strongly elevated toward this fissure, but even more strongly depressed along its margin. Brahcial (dorsal) valve rather evenly convex. Surface covered with minute circular pits more or less arranged in radiating furrows.
  • An unknown species of Trematis, much larger than T. millepuncta, occurs in the Lorraine-like strata south of Little Current. Larger than any other species hitherto found in the Richmond, but is not very well preserved for description.
  • Locality and Horizon. In the Waynesville, Snake island. Originally described from Cincinnati, Ohio, where it ranges from the Eden to the Richmond.

Hall (1875):

  • Shell small or medium sized, sub-orbicular, slightly transverse on the ventral side and lenticular in profile. Ventral valve strongly convex below the middle, more depressed above, and with a narrow, deeply depressed pedicle-opening extending to the cardinal border, the margins being flattened for a space nearly equal to the breadth of the opening. Dorsal valve more elongated than the opposite, most convex above the middle; beak pointed, and projecting considerably beyond the cardinal margin of the ventral valve, having a depressed or concave triangular area.
    Interior of the dorsal valve marked near the middle by two comparatively large, semi-circular or reniform muscular scars; the breadth across the two more than equals one-third the diameter of the valve, and in the center of the valve by a slight mesial septum.
    Surface strongly punctate in concentric curves passing from the center of the shell outwards, extending through the substance of the shell near the front margins of the valves, and distinctly marking the internal casts left by the decomposition of the shell; inner layers of the shell not punctate.