29.8" Fossil Fish (Phareodus & Mioplosus) Plate - Wyoming

This is a darkly preserved, 12" long Phareodus testis and 9" long Mioplosus labracoides association, both of which are the more uncommon species of fish from this formation. This large specimen was collected from the famous 18 inch layer of the Green River Formation in Wyoming. The slab of rock they're on measures 29.8" wide by 14.7 tall.

This large fish plate has been backed with a wood board and has two ring hangers for a hanging presentation.

About Phareodus

Phareodus is a genus of predatory freshwater fish found in the famous Fossil Lake deposits of the Green River Formation in Wyoming. It had a mouthful of sharp pointy teeth, making it a voracious lake predator. In fact, the name Phareodus actually means "to have teeth". Spines from other fish such as Mioplosus and Priscacara have frequently been found preserved in their stomachs.

Mioplosus is a genus of large extinct perciform fish that lived through the Eocene epoch. This genus is easily distinguished by an elongate fusiform body, double dorsal fins, and forked tail. Mioplosus was a solitary predator with large teeth: a few fossil specimens have been collected with other, smaller fish lodged in their throats. Most fossils of this genus are from the Tertiary-aged Green River Formation in Wyoming, though relatives of this genus are known to range throughout Asia and New Zealand. Mioplosus is also believed to be related to the modern pike-perch of the genus Sander (Stizostedion).

About The 18 Inch Layer Of Fossil Lake

Specimens of this quality come from the coveted 18-inch layer of the Green River Formation, a horizon renowned for producing exceptionally dark, detailed, and well-preserved fossil fish. The limestone from this layer is significantly harder and more durable than that found in many other parts of the formation, likely a result of the deep-water conditions under which it was originally deposited.

These conditions helped preserve fish in remarkable completeness, allowing exceptional specimens to be recovered largely intact. Locating them is a specialized process. The layer is often worked at night using low-angle lighting, which reveals the subtle raised contours created by a fossil fish—particularly the backbone—hidden beneath the surface of the limestone.

A view of the 18 inch layer of the Green River Formation at the Lindgren quarry near Kemmerer, Wyoming.
A view of the 18 inch layer of the Green River Formation at the Lindgren quarry near Kemmerer, Wyoming.


Once identified, the surrounding rock is carefully cut away and the specimen is transported to a preparation laboratory. Because the fossil may lie as much as an inch beneath the surface, exposing it requires painstaking work under magnification. Skilled preparators use fine hand tools to gradually remove the overlying limestone, revealing the fossil in extraordinary detail while preserving the delicate bones beneath.

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DETAILS
SPECIES
Phareodus testis & Mioplosus labracoides
LOCATION
Kemmerer, Wyoming
FORMATION
Green River Formation, 18 Inch Layer
SIZE
29.8 x 14.7" shale
CATEGORY
ITEM
#144006
GUARANTEE
We guarantee the authenticity of all of our specimens.