Knightia eocaena

Knightia was a secondary consumer, feeding mainly on algal forms and diatoms, as well as some smaller fish.  They were schooling fish, and because of this they are frequently found together in mass mortality layers.  Length normally 5″ to 7″



Diplomystus dentatus

The Diplomystus is a non-clupeoid clupeomorph fish distantly related to modern-day extant herrings, alewifes, and sardines.  They commonly preyed on small fish such as Knightia.  Length normally 5″ – 8″ or 16″ – 20″



Mioplosus labracoides

The Mioplosus is the ancient fish in our quarry that most resembles the modern day trout.  Length normally ranges from 10″ to 18″.



Notogoneous osculus

Typically, this fish fed on plants and decaying animals on the lake bottom.  Few young have been found in Fossil Lake, suggesting that it spawned in streams and its fry developed there.  Length typically 20″.



Phareodus encaustus, Phareodus testis

Sharp teeth indicate that this fish was a piscavore (fish eater).  In fact, remains of Mioplosus and Priscacara are often found in their stomaches.  The long pectoral fins of adults may extend for a third of their length.  Length from 12″ to 26″.



Priscacara liops, Priscacara serrata

Masses of P. liops have been found, suggesting they formed schools. P. serrata, with rounded, crushing teeth suggesting it ate shrimp and crayfish, was much larger than P. liops.  Length normally 5″ – 6″.



Heliobatis radians

The stingray is usually found in seawater, but a few living freshwater species are known. They fed on the bottom in shallow water.  Length up to 18″.



Crossopholis magnicaudatus

A cartilaginous fish like sharks and rays, the fossils have no distinct backbone. Occasionally the rostrum (snout), skull, and fins ossified (turned bony) enough to be preserved. Length 20″ to 30″.



Turtle – Trionyx

Turtles are extremely rare in the Green River deposits.  The turtle pictured was a soft shell Trionyx, similar to but much larger than modern species.





An extremely rare occurrence, occurred when a predatory fish ate prey that was too large and became lodged in its throat.


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