5.7" Fossil Fish (Knightia) - Green River Formation

This is an 5.7" long, fish (Knightia) from the 18 Inch Layer, Green River Formation of Wyoming. It is very well preserved and shows bones and fin rays. Under magnification overlapping scales can be seen.

Priscacara is an extinct genus of perch from the Eocene (55.8-33.8 mya) Fossils of these fish are commonly found in the Green River Formation in Wyoming. Priscacara probably darted about freshwater streams and lakes, snatching at small creatures like snails, crabs, prawns, and tadpoles.

It varied in size. For example, P. liops is a smaller species, never exceeding
150 mm, whereas the larger P. serrata has been found up to 375 mm. Priscacara means, “Primitive head”. These tough looking, ray-finned fish packed a punch if something dared to swallow it. The genus is known for its protective dorsal and anal spines.

50 million years ago, Priscacara thrived in lakes fed by Uinta and Rocky Mtn. highlands. This plucky genus of perch, possibly related to modern-day Cichlids, is now entombed in the fine-grained, lime mud of Fossil Lake. Priscacara eventually went extinct by the end of cooler and drier Miocene (23-5.2 mya).

Today the wonderfully preserved fossils of Priscacara and other Fossil Lake fauna are collected in several private quarries around Kemmerer, Wyoming. The best preserved fish fossils come from the coveted 18 inch layer. This layer is collected at night under high-powered lights allowing the faint signs of fish under the surface to be more easily observed. These “ghosted” fish then must go through many hours of manual preparation to remove the overlying rock and reveal the Green River fauna in all of it’s glory.

It comes from the coveted 18 inch layer of the Green River Formation which produces darker and more detailed fish than the majority on the market. The rock from this layer is much harder and more durable. This layer is typically collected at night using low angle light to see the bump in the rock that the back bone creates. They then cut these fish out and take them to a lab where the fish which may be up to an inch under the surface of the rock are meticulously extracted under microscope with hand tools.


Comes with acrylic stand.
DETAILS
SPECIES
Knightia eocaena
LOCATION
Kemmerer, Wyoming
FORMATION
Green River Formation - 18 Inch Layer
SIZE
5.7" fish, 8.9 x 6.0" shale
CATEGORY
ITEM
#113983
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