Order Oncocerida Flower, 1950
Family Poterioceratidae Foord, 1888
Genus Poterioceras M’Coy 1844
Species curtum (Meek & Worthen, 1860)

Poterioceras curtum—a breviconic cephalopod species—first rose as Cyrtoceras curtum (Meek, 1860). Later, authors declared it to be the adult stage of Brachycycloceras (Furnish et al., 1962), as published in the Treatise of Invertebrate Paleontology (1964, Part K Mollusca 3, Furnish and Glenister). Researchers at the time considered today’s Brachycycloceras to be the deciduous portion of a larger conch, a cephalopod formerly and currently known as Poterioceras. Much later, new evidence and research redivided the names (Windle, 1973), prompting Niko and Mapes (2009, 2010) to redescribe species of Brachycycloceras. These actions placed this cephalopod back under the name Poterioceras.

Raymond (1910) listed the occurrence of Cyrtoceras curtum (=Poterioceras curtum) in the Brush Creek limestone and said it appeared restricted to that stratum. He also said the same about the gastropod Worthenia tabulata, but today, we know Worthenia exists in the Pine Creek limestone. Newer research shows that several former Brush Creek localities were Pine Creek or Woods Run marine zones (Harper, 2016). Detailed studies of conodont species have proven the exact correlation between many sites.

Poterioceras curtum from the Pine Creek limestone at SL 6445. These breviconic cephalopods show increased distance between parallel ornament lines as the creature ages.
Fig. 1.—Poterioceras curtum from the Pine Creek limestone at SL 6445. These breviconic cephalopods show increased distance between parallel ornament lines as the creature ages. The shell was rebuilt using paraloid B-72 as an adhesive. ID: CG-0500. Scale bar = 5 mm.
Poterioceras curtum from the Pine Creek limestone at SL 6445. Note the eye shape feature on the bottom left fragment.
Fig. 2.—Poterioceras curtum from the Pine Creek limestone at SL 6445. Note the eye shape feature on the bottom left fragment. The younger part of the shell is toward the bottom. ID: CG-0455. Scale bar = 1 cm.
Poterioceras curtum from the Pine Creek limestone at SL 6445. The specimen is only a fragment but does preserve part of the steinkern.
Fig. 3.—Poterioceras curtum from the Pine Creek limestone at SL 6445. The specimen is only a fragment but does preserve part of the steinkern. ID: CG-0436. Scale bar = 1 cm.
Poterioceras curtum from the Pine Creek limestone at SL 6445
Fig. 4.—Poterioceras curtum from the Pine Creek limestone at SL 6445. ID: CG-0700 Scale bar = 5 mm.

References

  • Furnish, W. M., Glenister, B. F., & Hansman, R. H., 1962. Brachycycloceratidae, Novum, Deciduous Pennsylvanian Nautiloids. Journal of Paleontology, 36(6), 1341–1356.
  • Meek, F.B., and Worthen, A.H., 1860, Description of new Carboniferous fossils from Illinois and other western states. Proceedings of the Academy of Natural Sciences of Philadelphia 12:447-472
  • Shimer, H. R., Shrock, R. R., 1980. Index Fossils of North America, Page 539
  • Sturgeon, M. T., Windle, D. L. Jr., Mapes, R. H. and Hoare, R. D., 1997. Pennsylvanian cephalopods of Ohio. Part 1, nautiloid and bactritoid cephalopods. Ohio Division of Geological Survey, Bulletin 71, p. 1–191.

Late Carboniferous Fossils from the Glenshaw Formation in Armstrong County, Pennsylvania

Localities: Locality SL 6445 | Locality SL 6533

Trilobita | Crinoidea

Bivalvia: Allopinna | Parallelodon | Septimyalina

Cephalopoda: Metacoceras | Poterioceras | Pseudorthoceras | Solenochilus

Gastropoda: Amphiscapha | Bellerophon | Cymatospira | Euphemites | Glabrocingulum | Meekospira | Orthonychia | Patellilabia | Pharkidonotus | Retispira | Shansiella | Strobeus | Trepospira | Worthenia

Brachiopoda: Cancrinella | Composita | Isogramma | Linoproductus | Neospirifer | Parajuresania | Pulchratia

Chordata: Petalodus | Glikmanius