The study examined rocks and fossils from the Chinle Formation to investigate the then-tropical environment back in Late Triassic, around 235 to 201 million years ago. By focusing on this formation, the team conducted the most intensive study of Late Triassic vertebrates of North America.
From the area, which at that time was around the same latitute as India today, the researchers discovered hints of extreme temperature fluctuations, high atmospheric carbon dioxide level, and widespread wild fires.
Such climate swings would have greatly affected vegetation, with individual plant group numbers varied repeatedly over time. The constant change would have prevented the diversification of larger animals that heavily depended on particular plants, which explains why only small predatory dinosaurs like Coelophysis and Tawa existed at that time.