Juvenile Green River Fossil Fish Mioplosus labracoides
mm = 1 inch): Fish fossil is 104 mm in length on a 128 mm by 75 mm matrix.
Site: Green River Formation, Fossil Lake, Kemmerer, Wyoming
This 50 million year old, Eocene-Era fossil fish comes from one
of the world's famous Laggerstatten, the Green River Formation in
Wyoming. A small portion of the fish fossils from Green River exhibits
such fine preservation. The significant extent of soft-tissue preservation
that makes the site famous is evident in this specimen.
Mioplosus labracoides is believed to have been a voracious predator
among the Green River fish fossils. Failure to find its numbers
in mass mortality leads to further conjecture that it was a solitary
hunter. A member of the Family Percidae, it has numerous relatives
in Northern Hemisphere fresh water as well as fossil relatives in
Asia, Europe and New Zealand. It is known as a predatory species
as determined from its many pointed teeth, and the fact that several
have been found with fish lodged in its throat. It may be related
to the modern-day pike of the genus Stezostedion.
Distinguishing features include double dorsal fins and a fan-like
tail. Mioplosus is uncommon in the Green River formation, especially
the fish of this size and of this exceptional quality of preservation
(both bone detail and some soft-tissue preservation are evident).
This is a juvenile example. See my other offerings for subadult
to adult specimens.
fossil pictures to enlarge