Knightia alta Prehistoric Fossil Fish Osteichthyes Bony Fish Eocene Terziary Collection (2)

Knightia is a genus of extinct fish belonging to the subclass of the Actinopterygii, family Clupeidae. It lived between the middle Paleocene and the middle Eocene (60 - 45 million years ago) and its fossil remains are abundant in the United States (Wyoming and Montana).
The appearance of this fish was very similar to that of a herring or a sardine, to which it is closely related. It rarely exceeded 20 centimeters in length. Knightia's body was slim and agile, equipped with fins that suggest fast and active swimming.
Knightia is a typical representative of the Clupeiformes, a large order of fish currently represented by numerous species, including herring, anchovies and sardines. In particular, Knightia appears to be a member of the Pellonulinae subfamily, which currently includes numerous freshwater forms.
Knightia fossils are the most common among those found in the famous Green River formation in Wyoming, where fish remains are perfectly preserved.
Like today's herring, Knightia also had to feed mainly on very small organisms, such as algae and insects, and formed numerous schools. In the center of the Fossil Lake deposit, where the deepest areas of the lake are presumed to be, hundreds of individuals were found crowded together, one next to the other. This is probably the result of mass deaths, perhaps due to temperature changes or changes in chemical values in the water, caused by the proliferation of algae. This hypothesis arose from the fact that today's herring are not adapted to sharp changes in temperature. This fish was exceptionally important in the Green River ecosystem because it was included in the diet of most predatory fish in the same habitat.
The Knightia alta species is distinguished from its similar Knightia eocaena by its wider belly, as well as being rarer than the latter.
The Knightia genus is the Wyoming State Fossil.