Official State Fossil of Tennessee
Tennessee designated Pterotrigonia (Scabrotrigonia) thoracica as the official state fossil in 1998. "Ptero" (thankfully it has a nickname) was a bivalve of the Cretaceous Age (a modern-day bivalve creates the state gem - Tennessee river pearl). All State Fossils
Fossils of this extinct prehistoric creature are found in the Coon Creek Formation of West Tennessee. Pterotrigonia was a shallow-burrowing suspension feeder that inhabited the ocean floor of West Tennessee 70 million years ago. The fossil shells of Pterotrigonia are abundant and easily recognized by collectors.