An undated image of Afrodelatorrichnus ellenbergeri, a set of foot and hand prints of a four-legged dinosaur, is seen preserved in a layer of sandstone in South Africa alongside an interpretive sketch of the trails, in a combination of photos released in 29 January 2020. Bordy et al. 2020 PLoS One / Disclosure via REUTERS
WASHINGTON (Reuters) – About 183 million years ago, during the early Jurassic period, huge amounts of lava flowed across the landscape in what is now South Africa, turning the environment into a land of fire.
But fossil footprints described by scientists on Wednesday showed that intrepid dinosaurs and other animals managed to inhabit this region – now the semi-arid region of Karoo, in South Africa – during calmer periods between volcanic eruptions.
These "Karoo firewalkers", as Emese Bordy, of the University of Cape Town, called them, were some of the last animals that lived in this inhospitable region before it was swallowed by melted rocks.
The researchers found a layer of sandstone on a farm in central South Africa with five fossil tracks left by at least three different animals that crossed the wet and sandy banks of a stream. One was a relatively small dinosaur, with two legs and a meat eater, the other was an equally small dinosaur, with four legs, apparently a plant eater, and the third may have been a primitive mammal.
"For short periods, streams started flowing again, the sun shone, plants grew and animals, including dinosaurs, grazed and hunted," said Bordy, who led the research published in the journal PLOS ONE. "This is attested by the footprints of dinosaur vertebrates that eat meat and vegetables, plant debris, sediments from streams and lakes, to name just a few."
"The properties of the sandstone allow us to say that the strips were deposited in seasonal streams that occur during flood events," added Bordy, whose team also included graduate students Akhil Rampersadh, Miengah Abrahams and Howard Head. “Hot was hot at that time, too. So no, they didn't walk in the lava. "
During that period, there were major species extinctions, mainly in the oceans, caused mainly by gases emitted by immense lava flows that poured the land surface in South Africa. Even when the landscape incinerated, the lava flows changed the chemistry of the atmosphere and of the seas.
Fossil footprints, in the absence of skeletal fossils, sometimes offer the only evidence that animals were present in an ancient environment. The sandstone that contained the tracks was sandwiched between layers of volcanic rocks, revealing an image of a functioning ecosystem that has survived despite threats of devastation by new eruptions.
"This story helps us to change the way we view life in stressful and hostile environments and thus improves our understanding of the history of life on Earth," said Bordy.
Reporting by Will Dunham; Editing by Sandra Maler
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