13.7" Mioplosus With Diplomystus - Wyoming

This is two fossil fish from the Green River Formation near Kemmerer, Wyoming. The larger is a 13.7" Mioplosus, one of the more uncommon species from the formation. The smaller is a 4.8" Diplomystus, one of the most common. This specimen shows bones, fin rays and scales. This specimen has been stabilized with adhesive to protect the fossils. The cluster of dark spots near the top of the specimen are coprolites, fossilized fish feces.

It comes with an acrylic display stand.

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).

Knightia is an extinct genus of schooling, ray-finned, spindle-shaped, bony fish that shares a family with herrings and sardines. They lived in the freshwater (lacustrine) environments of North America and were eaten by just about everything that was bigger. They ate insects and smaller fish, and used gill rakers to feast on plankton. Knightia eocena is the largest of the three species of Knightia, with a typical length of about 15 centimeters. It is the state fossil of Wyoming.

These fish had rows of dorsal and ventral scutes running from the back of the head to the medial fins. They had heavy scales, and small conical teeth. They are popular finds in the Wyoming lagerstätte, and were a primary food source to the large and hungry vertebrates of that once hunted the Green River Formation.

The Green River Formation is an Eocene geologic formation that records the sedimentation in a group of intermountain lakes in three basins along the present-day Green River in Colorado, Wyoming, and Utah. The Eocene spanned approximately 55.8 to 33.8 million years ago. This formation has distinct stratigraphy that displays alternating light and dark layers representing seasonal erosion and deposition.

Freshwater basins, charged by the Uinta Mountains on the Wyoming-Utah border, contained an enormous representation of taxa. The beginning of the Eocene was marked by warm upper latitudes, a greenhouse atmosphere rich in methane and carbon dioxide, and local climates stabilized by large lakes populated by such creatures as crocodiles. Fossil Lake in Wyoming, of which the Green River Formation includes, is known for its well-preserved warm, lacustrine ecology.

The end of the Eocene was dramatically different, with the onset of icehouse climate characteristics, a change in atmospheric chemistry, and possible bolide impacts. The Green River fossils date about 48 million years, but cover several million years, including the transition between the moist early Eocene climate and the slightly drier mid-Eocene.
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DETAILS
SPECIES
Mioplosus labracoides, Diplomystus dentatus
LOCATION
Kemmerer, Wyoming
FORMATION
Green River Formation
SIZE
13.7" mioplosus, 4.8" diplomystus, 18.9 x 9.3" shale
CATEGORY
ITEM
#122666
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