Coelophysis (/sɛˈlɒfɪsɪs/ se-lOF-iss-iss traditionally; /ˌsɛloʊˈfaɪsɪs/ SEL-oh-FY-siss or /ˌsiːloʊˈfaɪsɪs/ SEE-loh-FY-siss, as heard more commonly in recent decades[3]) is a genus of coelophysid theropod dinosaur that lived approximately 228 to 201.3 million years ago[4] during the Late Triassic period from the Carnian to Rhaetian ages in what is now the southwestern United States.[5] Megapnosaurus was once considered to be a species within this genus,[6] but this interpretation has been challen