Diplomystus Fish Fossil from Green River.
Diplomystus is an extinct genus of freshwater, ray-finned predators that are distantly related to modern herrings and sardines. Diplomystus has a distinctive jaw that protrudes aggressively outward from the mouth at an angle that allowed it to feed in surface waters and devour such prey as the smaller, schooling, Knightia.
50 million years ago, in the Eocene (55.8 mya to 33.8 mya), D. dentatus thrived in lakes fed by Uinta and Rocky Mtn. highlands. A voracious predator and delicious prey, D. dentatus is uniquely entombed in the fine-grained, lime mud of Fossil Lake.
The anoxic conditions at the bottom of Fossil Lake slowed bacterial decomposition, prevented scavengers from disturbing corpses, and most interestingly, suffocated creatures that ventured into the oxygen-starved aquatic layer. The result is a miraculous exhibition of Eocene biota in a subtropical, aquatic community within sycamore forests teeming with creatures such as freshwater stingrays, dog-sized horses, menacing alligators, early flying bats, and one of the first primates.
By the end of the Eocene, Earth developed icehouse climate characteristics and had a change in atmospheric chemistry. The effects of bolide impacts may also have contributed to the eventual loss of flora and fauna at once verdant latitudes.
Today the wonderfully preserved fossils of Diplomystus 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.
The lake itself is known as "Fossil Lake" and it existed 50 million years ago in what is now Wyoming and is believed to have covered approximately 930 square miles. It had an unusual chemistry that inhibited the decay and scavenging of dead organisms while think layers of limestone and organic matter accumulated. This special set of circumstances has lead to the beautiful preservation of fish and other fossils within the Green River Formation.
Measures 8 inches x 6 inches
Thank you for your interest in my curated selection of rare and unusual pieces! We have taken pride for over 20 years in our excellent reputation, and strive to satisfy our clients' exact needs. Please note that we take great care in accurately describing our items, and we support that with a money back guarantee. If you receive a product that is not as described, we will promptly refund the cost once the item has been returned in good order. If you have any questions or require further images/information in order to make a decision please do not hesitate to contact us.
Thanks and Best Regards,
David Dixon and the Strange Imports Team