Fish Diplomystus sp.

Diplomystus is a genus of herring fish widely distributed in Eocene freshwater reservoirs. The most representative specimens are known from the Green River Formation. A body extending anteriorly and a large head is characteristic of these fish. This specimen belongs to larger fish of the genus Diplomystus, but usually they are smaller in size. Like all herring fishes, Diplomystus is a predator, and the little Knightia fish, a common inhabitant of Green River, is among its victims.

Collectors value the Green River Diplomystus for its impressive appearance and good state of preservation. Thanks to the fine calcareous silt that soaked the fish carcass after its death, even the smallest fin bones as well as body contours are preserved.