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!