Priscacara Fossil Fish, from Green River Formation, Wyoming, U.S.A. (No.621)

Priscacara is an extinct genus of perch from the Middle Eocene. It is characterized by a sunfish-like body and its stout dorsal and anal spines. The fish is best known from the Green River Shales of Wyoming, Utah and Colorado. Mass deaths of Priscacara suggest it formed schools

Two species are recognised, of which the smaller species, P. liops is the most common.

P. serrata, the second of the two species of Priscacara differs from the P. Liops by number of dorsal and anal fin rays as well as possibly a coarser serrated rear edge of the preopercle in P. serrate.

P. liops also has small conical teeth on the pharyngeal jaw, whereas P. serrata has large grinding toothplates, suggesting a diet of snails and crustaceans.