Harsh climate was a dinosaur deterrent

DINOSAURS failed to populate the tropics for more than 30 million years because of an unpredictable and harsh cl i mat e , ac c or d i ng to research.

Extreme droughts and wet seasons as well as raging wildfires prevented large longnecked herbivore dinosaurs (sauropodomorphs) in the Triassic period from living around the equator as the conditions meant the vegetation needed could not grow.

Dr Jessica Whiteside, of Southampton University, said: “The conditions would have been something similar to the arid western United States today, although there would have been trees and smaller plants near streams and rivers and forests during humid times.

“The fluctuating and harsh climate with widespread wildfires meant that only small two-legged carnivorous dinosaurs, such as coelophysis, could survive.”

The research, published in Proceedings of the National Academy of Sciences, has found that elevated CO2 levels would have also prevented the large sauropods such as the brachiosaurus, diplodocus and brontosaurus from populating the tropics until 15 million years after they had become abundant at higher latitudes north and south of the equator and 30 million years after they first appeared on Earth.

Scientists took rock samples from a location called Ghost Ranch in New Mexico, where a number of Triassic dinosaur fossils have been discovered. The rocks were deposited by rivers and streams between 205 million and 215 million years ago, during the Late Triassic Period.

Study co-author Sofie Lindstrom, of the Geological Survey of Denmark and Greenland, said: “When these rocks were deposited during the late Triassic, northern New Mexico was very close to the equator at about 12 degrees north in latitude – around the same latitude as the southernmost tip of India sits today.”