Science, Tech, Math › Animals & Nature Knightia Share Flipboard Email Print Knightia (Nobu Tamura). Animals & Nature Dinosaurs Basics Paleontologists Carnivores Dinosaurs & Birds Herbivores Marine Reptiles Prehistoric Mammals Amphibians Birds Habitat Profiles Mammals Reptiles Insects Marine Life Forestry Evolution View More By Bob Strauss Science Writer B.S., Cornell University Bob Strauss is a science writer and the author of several books, including "The Big Book of What, How and Why" and "A Field Guide to the Dinosaurs of North America." our editorial process Bob Strauss Updated March 17, 2017 Name: Knightia; pronounced NYE-tee-ah Habitat: Rivers and lakes of North America Historical Epoch: Eocene (55-35 million years ago) Size and Weight: About six inches long and a few ounces Diet: Small marine organisms Distinguishing Characteristics: Small size; herring-like appearance About Knightia Most fossils from the Eocene epoch are well out of the reach of ordinary consumers, but not so the small prehistoric fish Knightia, thousands of specimens of which have been discovered in Wyoming's Green River formation (in fact, Knightia is Wyoming's official state fossil). Thanks to their abundance, it's possible to buy a well-preserved Knightia fossil for under $100, a bargain compared to the average dinosaur! (Buyer beware, though: whenever you purchase a fossil, especially online, it's essential to check its provenance--that is, whether it really is a genuine specimen of Knightia or simply a baby salmon that has been crushed between two bricks.) Part of the reason there are so many Knightia fossils is that there were so many Knightia--this six-inch-long fish assembled in vast schools throughout the lakes and rivers of Eocene North America, and lay near the bottom of the aquatic food chain (meaning that these huge populations of Knightia sustained larger, scarcer predators, including the prehistoric fish Diplomystus and Mioplosus). Befitting its small size, Knightia itself fed not on fish, but on tiny marine organisms like plankton and diatoms, and it was very herring-like in its appearance and behavior--so much so that it was originally classified as a species of the herring genus Clupea.