Bivalvia » Parallelodon

Subclass Autobranchia Grobben, 1894
Infraclass Pteriomorphia Beurlen, 1944
Order Arcida Gray, 1854
Superfamily Arcoidea Lamarck, 1809
Family Parallelodontidae Dall, 1898
Genus Parallelodon Meek & Worthen, 1866

Parallelodon carbonarius (Cox, 1857) is a bivalve first described from the Coal Measures of Kentucky. It ranges from the older Pottsville Group to the younger Conemaugh Group in Ohio (Hoare et al., 1979), and I find it in the Pine Creek limestone of Armstrong County, Pennsylvania (Fig. 1C). Morningstar (1922) wrote that “It is characterized by surface sculpture of prominent, regular, radiating plications which become considerably larger and stronger on the flattened posterior portion below the hinge line”.

Hoare, Sturgeon and Kindt (1979, pl. 3, figs. 4–8) give five good figures of the species in Pennsylvanian Marine Bivalvia and Rostroconchia of Ohio. Cox described it as Arca carbonaria (Cox, 1857, pl. 8, fig. 5), but the online versions of that report lack the lithographed plates.

References

• Cox, E. T., 1857. Paleontological report of coal measure Mollusca, in Owen, D. D., Third Report of the Geological Survey in Kentucky. Kentucky Geological Survey, v. 3, pp. 557–576, pls. 7–10.
• Hoare, R. D., Sturgeon, M. T., and Kindt, E. A., 1979. Bulletin 67: Pennsylvanian Marine Bivalvia and Rostroconchia of Ohio. State of Ohio Div. of Geological Survey, 77 p., 18 pls.
• Mark, C. G., 1912. The Fossils of the Conemaugh Formation in Ohio, in Condit, D. D., Conemaugh Formation in Ohio. Geological Survey of Ohio, Fourth Series, Bulletin 17, pp. 261–326, pls. 13–16.
• Morningstar, H., 1922. Pottsville fauna of Ohio. Ohio Geological Survey, Bulletin 25, 312 p., 16 pls.