Named By: Jordan - 1907.
Classification: Chordata, Actinopterygii, Clupeiformes, Clupeidae, Pellonulinae.
Species: K. alta, K. branneri, K. eocaena, K. humulus.
Diet: Zooplankton, small invertebrates and possibly very small fish and fry.
Size: Usually up to 25 centimetres long, the largest specimens slightly bigger.
Known locations: USA, Wyoming - Green River Formation.
Time period: Eocene.
Fossil representation: So numerous no one knows exactly how many specimens have been recovered.
were small freshwater fish often described as ‘herring-like’ that
lived in North America during the Eocene period. Also because
Knightia were schooling fish they are often
preserved still in their
shoals with some specimens even being preserved on top of each other.
This is why so many fossils of this fish are known, and why Knightia
specimens are one of the most commonly traded fossils on the market.
The majority of Knightia specimens are quite small, but some large specimens around twenty-five centimetres long are known. Knightia are often so well preserved that the scutes than run from the head to the median (middle) fins across the back and belly are often visible. Although Knightia may seem a small and unimportant fish, their sheer numbers strongly suggest that they would have formed an important part of their ecosystems biomass, being an abundant food supply for predators.
Other fish from the Green River Formation include Heliobatis and Diplomystus.