Ptychopteria flabellum

the only other Pelecyod that I've found while visiting the dump piles of Silica Shale, is Ptychopteria flabellum (Hall 1883). My ID is based on the 1975 book by Robert V. Kesling & Ruth B. Chilman: Strata and Megafossils of the Middle Devonian Silica Formation: Museum of Paleontology, Papers on Paleontology, No. 8, pgs. 134, 137, pl. 72.

It's a very distinct pectin type clam and most often found, or recognized, from the single left valve. It's this valve that has the distinct, heavy radial costae (ribbing) and is always pointing from upper left to lower right. Apparently the right valve is less ornamented, smaller and less convex than the left and is not found as often.



I have found several specimens of this species but this was the easiest to photograph. :)