Neithea texanus pelecypod from the Duck Creek formation of Texas

This is the pelecypod Neithea texanus from the Duck Creek formation of Texas. I found it in a creek in North Texas last fall. It looks very similar to a scallop but this particular specimen is missing the small "ears" that normally are present next to the beak and are part of the hinge line. Otherwise the shell has a triangular outline with a convex right valve and a slightly concave to flat left valve. There are strong, wide ribs on both valves and the rib pattern is reflected in the margin between the valves.

Right valve

Anterior

Left valve

Posterior

Profile

This specimen comes from the Duck Creek formation which is Cretaceous (Albian stage) in age.