Procambarus primaevus
Crustacean
Early Eocene
Green River Formation
Kemmerer, Wyoming, USA

33mm to tip of antenna freshwater crayfish on 63mm slab.

Arthropod. Crustacean.

Procambarus is a genus of freshwater crayfish – a group with a spotty fossil record. P. primaevus is one of the first invertebrates ever described from the Green River sandwich beds.  The genus still lives today in North and Central America, preferring warm, slow-moving river, stream, and marsh habitats.