Subclass Amphigastropoda Simroth, 1906
Order Bellerophontida McCoy, 1852
Superfamily Bellerophontoidea McCoy, 1852
Family Bellerophontidae McCoy, 1852
Genus Bellerophon Montfort, 1808

Bellerophon is reported from Western Pennsylvanian rocks, but there are none to report from the locations in this book yet. Several steinkerns are recovered, but Yochelson (REF) warned against attempting identification using steinkerns from this superfamily.

The following pages highlight ideal specimens from North Texas and show a large specimen from the Brush Creek limestone that could only be cut in half.

Bellerophon might be the most controversial gastropod genus in the Brush Creek and Pine Creek limestone. Several sibling genera were once named Bellerophon, and authors have erected nearly countless species in over 150 years. Several authors debated Bellerophon’s membership to the gastropods. Some confusion exists due to the order being extinct. They produced odd bilaterally symmetrical shells with two columns.

Yochelson (1967) believed that bellerophontaceans with a selenizone descended from the pleurotomariaceans, such as Shansiella. I could agree with this, yet we also know that in convergent evolution, the same feature can evolve at different times in unrelated groups.

Bellerophon sp. from the Finish Shale, Graham Formation, Stephens County, Texas.
Fig. 1.—Bellerophon sp. from the Finish Shale, Graham Formation, Stephens County, Texas. Specimens purchased online. A, CG-0607; B, likely a different species than A and C, with an elongated shell profile and a less narrow aperture flare, CG-0608; C, CG-0609. Scale bar = 5 mm.
Indeterminate Bellerophontid from the Brush Creek limestone at SL 6533.
Fig. 2.—Indeterminate Bellerophontid from the Brush Creek limestone at SL 6533. A–B, a very large specimen with a difficult-to-recover shell due to the nature of the limestone, CG-0510; A, both halves of the cut specimen, parietal callus at the arrow; B, close up of a nucleus, arrows note the boundary where newer shell material was laid down upon older material. Scale bar for A = 5 mm.

References

  • de Montfort, P. D., 1808, Conchyliologie systématique, et classification méthodique des coquilles; offfrant leurs figures, leur arrangement générique, leurs descriptions caractéristiques, leurs noms; ainsi que leur synonymie en plusieurs langues. Coquilles univalves, cloisonnées 1
  • Sedgwick, A., McCoy, F, 1850-1855, A synopsis of the classification of the British Palæozoic rocks; With a systematic description of the British Palæozoic fossils in the Geological museum of the University of Cambridge.
  • Simroth, H. 1906, Versuch einer neuen Deutung der Bellerophontiden. Sitzungsberichte Der Naturforschenden Gesellschaft Zu Leipzig, 32: 3–8.