8.5" Priscacara serrata | Green River Formation | Wyoming

Fish approx. size: 8.5"

Plate approx. size: 18" x 14"

Stand not included.

Order Perciformes

Family Moronidae - C. liops, P. serrata, H. hypsacantha, and undescribed Priscacara & Hypsiprisca species

P. serrata is perhaps the most popular and sought after of the Green River Formation fish fossils. The Moronidae are a family of perciform fishes, commonly called the temperate basses. P. serrata is an uncommon find compared to Cockerellites liops, which are often confused without proper examination and preparation. P. serrata are typically larger than C. liops.

Morphology
Priscacara serrata is a deep-bodied, laterally compressed fish exhibiting a sunfish-like profile. It typically reaches lengths of 6 to 16 inches (15 to 40 cm), though smaller and larger specimens occur. Its distinguishing features include:

• A prominent dorsal fin with both spiny and soft-rayed sections

• Notably serrated preopercle and opercle bones, which give the species its name (“serrata” meaning “serrated”)

• Well-developed pectoral and pelvic fins
  

Preservation & Significance
Priscacara serrata fossils are often preserved in exceptional detail, with visible fin rays, scales, and skeletal structure. These specimens are a hallmark of the lagerstätte preservation found in the Green River Formation. Entire schools of Priscacara have been found fossilized together, suggesting schooling behavior and providing insights into Eocene freshwater ecosystems.

Paleoecology
This species thrived in the subtropical, stratified freshwater lakes of the Eocene, preying on smaller fish, crustaceans, and aquatic invertebrates. It shared its habitat with other iconic Green River fishes like Knightia, Diplomystus, and Mioplosus.