Mariella bosquensis
Heteromorph
Late Cretaceous (Early Cenomanian)
Del Rio Clay
Waco, Texas, USA

21mm heteromorph.

Cephalopod.

Mariella is an ammonite genus that lived during the last part of the Early Cretaceous (Late Albian) and the first part of the Late Cretaceous (Early Cenomanian).  It has been found in many parts of the world (North America, Europe, Africa, Australia, and New Zealand).  In the Del Rio Clay of Texas it is often found pyritzed.