The
Caritodens demissa (Conrad, 1842) pelecypod fossil found in Jefferson County, Indiana USA (near Madison). Fossil dates to the Ordovician Period. The book
Index Fossils of North America by
Hervey W. Shimer and
Robert R. Shrock 1944 lists this fossil as
Pterinea demissa (Conrad, 1842) of the Upper Ordovician Period (Maysville-Richmond). It is described as "Distinguished by its strong concentric growth lines and large anterior ear." The genus
Pterina was named by
Georg August Goldfuss (1782-1848) in 1832. Original species named
Avicula demissa in 1842 by
Timothy Abbott Conrad (1803-1877) in the Journal of Academy of Natural Sciences in Philadelphia Volume VIII page 242, plate XIII, figure 3.
Thanks to Kenny for the image.
