Knightia and Diplomystus Association

This is a nice association piece from the Green River Formation with two species of fossil fish. It includes both a Knightia eocaena and a Diplomystus dentatus each of which is about 3.3 inches in length. They are both well preserved and contrast well with the creme colored matrix they were found in. This piece displays well on the included acrylic display stand.

About Knightia

Knightia is an extinct genus of small, schooling, ray-finned fish related to modern herrings and sardines. Abundant in the warm freshwater lakes of the Eocene Green River Formation, they fed on insects, plankton, and tiny fish, while serving as prey for nearly every larger predator in the ecosystem. The most common species, Knightia eocena, reached about 15 cm in length and is celebrated today as the state fossil of Wyoming.

These streamlined fish are recognized by their heavy scales, small conical teeth, and rows of dorsal and ventral scutes along the body. Their fossils are among the most iconic from the Green River Formation—an exceptional 48-million-year-old lake deposit in Wyoming, Colorado, and Utah known for preserving a remarkably detailed snapshot of ancient life in a warm, lake-rich Eocene landscape.

SPECIES

Knightia eocaena and Diplomystus dentatus

AGE

Eocene (~51 million years)