Bivalve species identification from Cretaceous (Glen Rose) in Uvalde County TX

[Mr.Marcus]

I need some help identifying these two specimens. I have collected and cleaned at least 50 of each specimen. The majority of them were found in the upper Glen Rose formation of Edwards, Real and Uvalde County Texas. I've been told that they are both called "deer hearts," even though they look different. Given the different physical characteristics (deep lines on the right specimen and "ears" on the left specimen), I'm guessing that they are different species. My best guess is either Arctica roemeri or Protocardia texana.

Thanks!

[tmaier]

I've been told that they are both called "deer hearts," even though they look different.

Common names are not standardized, so people can call them whatever they like and it is OK. There is no point in arguing about what is right in common names. "Beef heart" is common in Europe. Or just heart clam. Often there are several to a dozen common names for one type, and they are picky about details of species.

I still often learn common names as a easy-to-remember starting point for searching for the scientific name of the specimen.

Can't help you with these you have here... but "heart clam" is a good starting point.

[PFOOLEY]

Upper Aptian-Albian Bivalves of Texas and Sonora: Biostratigraphic, Paleoecologic and Biogeographic Implications

[Brazos Aaron]

The one with the lines is probably P. texana.