fossils

Late Triassic too hot for dinosaurs

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Franz
Anthony

Editor and Artist
An in-depth study of fossils from Ghost Ranch, New Mexico, has revealed temperature fluctuation and unstable environment during the Triassic Period. This likely prevented the diversification of larger dinosaurs until 30 million years after their appearance.

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.

The environment finally stabilized at the beginning of the Jurassic Period, around 200 million years ago. Only then, larger, warm-blooded herbivorous dinosaurs finally diversified, replacing the previously dominant crocodile-relative pseudosuchians of the Triassic – kickstarting the age of the dinosaurs.

Original findings published at PNAS.

Image Credit: Nathan Rogers

8e6ac47821297aeee8c843e680637dca

Franz
Anthony

Editor and Artist


http://sulc.us/7j0kr
http://www.eartharchives.org/articles/only-carnivores-could-handle-late-triassic-tropics/