A newly discovered dinosaur unearthed by UW-Madison paleontologists is reshaping our understanding of prehistoric reptiles.The fossils suggest the species lived in the northern hemisphere millions of years earlier than previously thought, according to a study published in the Zoological Journal of the Linnean Society by UW-Madison scientists and their research partners on Jan. 8, 2025.The discovery was made during a dig in Wyoming in 2013, where the team found bones dating back about 230 million years. High-precision dating confirms this makes the species the oldest dinosaur yet discovered in North America, according to the study. The fossils include: Ahvaytum bahndooiveche, the oldest known dinosaur from the northern hemisphere. A silesaurid, a close relative of early dinosaurs.Watch: UW-Madison scientists announce discovery of a new Dinosaur UW-Madison team discovers new DinosaurAccording to the study, these findings fill a critical gap in the record of early dinosaur evolution and distribution.The dinosaur, roughly the size of a chicken but with a long tail, is estimated to have been about three feet long.Its about time to watch on your time. Stream local news and weather 24/7 by searching for TMJ4 on your device.Available for download on Roku, Apple TV, Amazon Fire TV, and more.Report a typo or error