Priscacara serrata
Green River Formation
Middle Eocene
Lincoln County, Wyoming

Specimens of Priscacara do not come better preserved than this example. This fossil is from the zone immediately below the 18 in layer. The matrix is very dense and kerogen -rich and probably represents near anoxic conditions at the time of deposition. The fossils from this zone have extraordinary preservation, but preparation is very difficult and time consuming. The fish is 21 cm long. This is from our collection and is the finest that we have ever collected. The slab was broken during collecting and is repaired.
Priscacara serrata is relatively common in the Green River Formation although proportionately it makes up less than 1 percent of the total fish fauna where it occurs. This species is deep-bodied with stout spines and slightly rounded tail fin margin, with molar-like tooth pads in its throat suitable for crushing and grinding arthropods or even small mollusks. P. serrata can occasionally reach sizes of over 16 inches. These fish have been found as predators in aspiration specimens and with bones in its mouth or stomach indicating that it supplemented its diet with small fishes. This species is a real favorite of fossil collectors especially with the dorsal spines in an upright stance.