Trigonarca matheroniana  (d'Orbigny, 1844) is a pelecypod fossil. This genus might be known as Arca (Linnaeus, 1758). It existed during...

Pterotrigonia vaelsiensis  (Boehm, 1884) is a pelecypod fossil. It existed during the Cretaceous Period (about 120-70 million years ago ). ...

Pterotrigonia thoracica (Morton 1834) pelecypod is the official state fossil of Tennessee. It existed during the Cretaceous Period (about 7...