Dinosaur Mystery Solved: Here's Why There Were No Sauropods in the Tropics
Despite the fact that long-necked, herbivore dinosaurs (sauropodomorphs) were likely a common sight in the higher altitudes of Earth's supercontinent 30 million years ago, none of these species elected to head south. Now paleontologists think they have determined why it took an additional 15 million years for these massive dinos to move to the tropics.
According to a study recently published in the Proceedings of the National Academy of Sciences there may simply have not been enough food in the area to keep the ancestors of long-necked behemoths like Brachiosaurus, Diplodocus and Brontosaurus fed.
"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," lead-author Jessica Whiteside of the University of Southampton explained in a statement. "The fluctuating and harsh climate with widespread wild fires meant that only small two-legged carnivorous dinosaurs, such as Coelophysis, could survive."
This was determined after Whiteside and her colleagues collected rock samples from a location called Ghost Ranch, in New Mexico, where a number of Triassic dinosaur fossils have been discovered. According to the study, this region was once close to the equator at about 12 degrees north in latitude - prior to the slow division of continents over tens-of-millions of years.
Analyzing the isotopic signatures within these rocks, the researchers were able to identify some of the key climate conditions the region was going through 30 - 10 million years ago.
"Throughout this period, levels of CO2 were four to six times higher than the levels we observe today," Co-author Randall Irmis, a paleontologist at the Natural History Museum of Utah, said.
The expert explained that this was likely a localized affair due to a cycle of frequent and widespread wildfires, unlike rising global carbon levels today. In this way, the study is not exactly a commentary how we will lose all hope of a real "Jurassic World," if we stay on our current track for carbon emissions.
However, Irmis added that "the findings do indicate that if we continue our present course of human-caused climate change, similar conditions could develop and suppress equatorial ecosystems."
Keeping one eye on the future seems to be a duty of all scientists, even those who often are peering far into a past filled with rampant fires, scaly giants, and a lot of empty land.
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