8.8" Plate with Two Huge Fossil Fish (Knightia) - Wyoming

About Knightia

Knightia is an extinct genus of small, schooling, ray-finned fish related to modern herrings and sardines. Abundant in the warm freshwater lakes of the Eocene Green River Formation, they fed on insects, plankton, and tiny fish, while serving as prey for nearly every larger predator in the ecosystem. The most common species, Knightia eocena, reached about 15 cm in length and is celebrated today as the state fossil of Wyoming.

These streamlined fish are recognized by their heavy scales, small conical teeth, and rows of dorsal and ventral scutes along the body. Their fossils are among the most iconic from the Green River Formation—an exceptional 48-million-year-old lake deposit in Wyoming, Colorado, and Utah known for preserving a remarkably detailed snapshot of ancient life in a warm, lake-rich Eocene landscape.

About The Megalodon Shark

The megalodon was not only the biggest and baddest prehistoric shark that ever lived, it was the largest marine predator in the history of the planet. Today’s great white sharks would be a mere bite-size snack for this monster. It terrorized the diverse ocean waters around the world from 15.9 to 2.6 million years ago, from the late Oligocene to the early Pleistocene. This massive and extinct species of shark was estimated to grow to nearly 60 feet in length and has often been declared the greatest vertebrate predator that ever lived.



These mega-toothed sharks were a giant and more robust version of the great white. They had 276 teeth in 5 rows and, like today's sharks, shed their teeth throughout their lifetime. The largest megalodon teeth on record reached a staggering 7.5 inches (190mm)! Compare this to the largest great whites, whose teeth top out around 3 inches long. Wow!

Their teeth were bone-crunching and flesh-cutting tools evolved for grasping powerful prey such as baleen whales. Fossil evidence supports that megalodon focused its attack on the hard, bony parts of its prey, such as rib cages, flippers, shoulders, and spines, effectively disabling large whales and harming major organs such as the heart and lungs. This strategy explains their thick, robust teeth.

Megalodon had a cosmopolitan (global) distribution and its giant teeth can be found in deposits throughout the world. Some are collected on land in phosphate deposits, while many are collected from rivers and coastlines after eroding out of the rocks. This contributes to the water-worn, polished appearance of many teeth.

The standard measure for megalodon teeth is slant height, or the longest edge of the tooth. Adult megalodon teeth were typically in the 4 to 5 inch range: teeth over 6 inches are rare and represent super-sized individuals. Only a handful of teeth have ever been found over seven inches.

No one knows for sure why the megalodon went extinct 2.6 million years ago, but the cooling of the climate and gradual disappearance of many of the large whales it relied on for food are suspects.

About Fossil Lake

50 million years ago, in the Eocene epoch, these fish thrived in Fossil Lake, which was fed by the Uinta and Rocky Mountain highlands. The anoxic conditions at the bottom of Fossil Lake slowed bacterial decomposition, prevented scavengers from disturbing corpses, and, most interestingly, suffocated creatures that ventured into the oxygen-starved aquatic layer. The result is a miraculous exhibition of Eocene biota: a subtropical aquatic community within sycamore forests, teeming with creatures such as freshwater stingrays, dog-sized horses, menacing alligators, early flying bats, and one of the first primates.