Morrison Formation

Ornitholestes

Ornitholestes, “the bird thief”, was a small meat-eating dinosaur which lived in western North America during the late Jurassic Period about 154 million years ago. Since its discovery in the year 1900, Ornitholestes has come to be regarded as the… Read More ›

Kepodactylus

Kepodactylus was a species of pterosaur which lived in western North America during the late Jurassic Period 150 million years ago. In 1992, a nearly-complete Stegosaurus skeleton was discovered in Garden Park, Colorado within the rocks of the Morrison Formation…. Read More ›

Polyacrodus

NOTE: This article was originally published on May 4, 2022. On December 30, 2025, it was updated and re-uploaded. Polyacrodus was a genus of prehistoric shark, composed of several species, with fossils found in North America, South America, Europe, Asia, and… Read More ›

Gargoyleosaurus

When people think of “armored dinosaurs”, they generally think of two kinds of creature: the stegosaurs and the ankylosaurs. Both of these groups belong to the dinosaur sub-order Thyreophora, which means “armor-bearing” in ancient Greek. The dinosaur group Ankylosauria or… Read More ›

Brachiosaurus

There are some dinosaurs that everybody thinks of when they hear the word “dinosaur”. Among these is a very large sauropod which was the reptilian analog of a giraffe. I am, of course, talking about Brachiosaurus. Brachiosaurus is one of… Read More ›