Eocene Green River Knightia
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Knightia eocaena
Green River Formation
Middle Eocene
Lincoln County, Wyoming
Sold Scott Beech
This is an interesting example of the species from the Fossil Butte Member of the Green River Formation. It displays and an adult and juvenile of the same species. The preservation is excellent. The adult is 11 cm. and the juvenile is 5 cm.
Knightia eocaena is the most important and most common fish species in the Fossil Lake early Eocene. It formed immense schools that sometimes were killed en masse and are found preserved in mass-mortality layers in this famous lagerstatten. Sudden changes in water temperature or chemistry are suspected to cause the mass die-offs. Their schooling behavior persisted throughout their lives as evidenced by mortality layers of both juvenile and adult fishes. This species was a keystone of the food web in Fossil Lake. It fed on algae and zooplankton and in turn was prey for a wide variety of predatory fish.
$90