TETRAPOD REMAINS FROM THE EWING LIMESTONE (CARBONIFEROUS: KASIMOVIAN) OF OHIO

The Ewing Limestone is a gray discontinuous limestone found throughout the Appalachian Basin of eastern Ohio and western Pennsylvania. A part of the Glenshaw Formation within the Conemaugh Group (Carboniferous: Kasimovian), the Ewing represents a freshwater paleoenvironment situated between the Portersville and Ames marine zones. The Invertebrate taxa reported previously from the Ewing Limestone include serpulid worms assigned to Spirorbis anthracosia as well as ostracods and bivalves. Stromatolite beds are abundant in some places as well, though they are topped by bedded carbonate layer. The vertebrate fauna of the Ewing Limestone is known to include xenacanthiform sharks and osteichthyans. Putative reptilian remains have also been reported, but are underinvestigated.

Here, we report additional tetrapod remains from the Ewing Limestone in the form of a partial embolomere jaw recovered from just above a stromatolite bearing layer in Guernsey County, Ohio. Paleozoic tetrapods have a long history of study in Ohio and Carboniferous taxa generally occur in terrestrial settings rather than stromatolite-rich freshwater limestones. Given the fragmentary nature of this specimen and the local sedimentology being atypical for Conemaugh and Allegheny Group tetrapods sites, we suggest that these remains may have washed into the Ewing Limestone from another freshwater ecosystem elsewhere in the Appalachian Basin, which would imply that it lived in a similar ecosystem to other Conemaugh tetrapods such as Eryops, Neopteroplax.