Discovered in the Judith River Formation area of Montana in 1876, Zapsalis was a theropod dinosaur. This species lived in North America approximately 75 million years ago. Evidence of the Zapsalis was found only in teeth fossils.
The name Zapsalis comes from the Greek words for “thorough” and “pair of scissors.” The Zapsalis teeth found in Colorado are classified by vertical grooves, straight rear edges, and a round shape. Based on these teeth, Zapsalis had stout, boxy skulls and heavy legs. These dinosaurs were built for strength more than speed. Their sharp, powerful teeth also indicate that Zapsalis were carnivores.