Plicatula mullicaensis Pelecypod from the Corsicana formation

Here is an interesting Pelecypod from the Cretaceous sediments of Texas. It's Plicatula mullicaensis and the small shell has remnants of spines that coat the shell surface.  It comes from the Corsicana Fm. in Bexar County, Texas and is around 68 million years old which places it in the Maastrichtian stage of the Late Cretaceous.

The shell is roughly oval in shape and relatively flat. Although the flatness could be due to the shell being compressed during/after fossilization. Plicatula mullicaensis is considered an oyster although it does not look like the ones we see on our plates today. The genus is extant in the warm waters of the Gulf of Mexico but they look different than this fossil does and they are call "Cat's Paws".

Right valve

Left valve

I took these pictures a few years ago and I can't really remember which angle of the shell they are showing. The first picture is of the anterior I believe but the other shots may just be profile views. The shell is so flat it's hard to tell!

I purchased this fossil from a collector in Texas.

Exogyra costata from Texas

I immediately recognized this next shell when I first unwrapped it from the parcel it came in. It belongs to the genus Exogyra and likely is the species E. costata. It comes from the Corsicana formation (Cretaceous, Maastrichtian stage) near San Antonio, Texas. It looks very similar to E. costata shells found in the Navesink thru Mt. Laurel formations ( also Cretaceous, Maastrichtian stage) of New Jersey and Delaware like this one.

Left valve top

Right side profile

Anterior

Left side profile

Posterior

Interior of left valve. It still has a slight mother of pearl sheen to the interior!

I received this in a batch of fossils that I won in an auction on the Fossil Forum site. Thanks, Travis, for the cool fossil!

Diplodetus americanus and Mecaster batensis echinoids from Texas

This is an echinoid called Diplodetus americanus from the Corsicana formation (Cretaceous, Maastrichtian stage) found in Bexar County, Texas.

 Adapical surface (top)

Posterior (rear)

Adoral surface (underside or bottom)

 

Anterior (front)

Left profile

Right profile

Then we have an older cousin in Mecaster batensis which comes from the Boquillas formation (Cretaceous, Turonian stage) of Val Verde County, Texas. This fossil looks very similar to Diplodetus but it's about 22 million years older.

Adapical surface (top)

Posterior (rear)

Adoral surface (underside or bottom)

 Anterior (front)

Left profile

Right profile

I got both specimens from Dan Woehr who does a very cool write up on his fossiling adventures over at "Meanderings of a Texas Fossil Hunter". Thanks Dan for the cool Echie fossils!