Discovered in 1908 in the Morrison Formation of Wyoming, the Alcovasaurus lived in the United States during the Late Jurassic Period. It was initially classified as a stegosaurus, but researchers later identified it as a new species. In 2016, it was renamed Alcovasaurus.
The Alcovasaurus was a herbivore characterized by large spikes on its back. It also had two slender spikes located in its tail. Experts agree that the spikes were used as weapons. According to the fossils, the spikes could reach up to thirty-two feet in length. Heavy muscle mass in the Alcovasaurus’ legs and tail made it easy to swing their massive tails to hit opponents.