Gondwana land is back in focus as the origins of dinosaurs can be traced to Sahara and Amazon
By Kiran N. Kumar
Scientists have long uncovered new evidence shedding light on the origins of diverse plant and animal species, tracing their roots to the ancient supercontinent Gondwana land. Adding to this discovery, researchers have now pinpointed the likely birthplace of dinosaurs.
A recent study suggests that dinosaurs originated in regions of ancient Gondwana, which today are split between South America and Africa, with their cradle of evolution centered around areas now known as the Sahara Desert and the Amazon Rainforest.
READ: Extinct fish brought back to life 100 Years after (September 29, 2022)
Gondwana’s remnants account for nearly two-thirds of today’s continents, spanning South America, Africa, Antarctica, Australia, Zealandia, Arabia, and the Indian subcontinent. Some of the oldest dinosaur fossils, dating back 245-230 million years, have been discovered in locations like Brazil, Argentina, and Zimbabwe.
According to the study, these fossils indicate that dinosaurs likely originated in hot, arid equatorial regions such as the ancient Sahara and Amazon. These areas could still hold critical clues about the early stages of Earth’s evolutionary history during the Triassic Period.
At the time, all continents were part of the supercontinent Pangaea, with Gondwana forming its southern expanse. “Our research highlights Gondwana as a probable cradle of dinosaur evolution,” said Joel Heath, lead author of the study and a paleontology doctoral researcher at University College London and the Natural History Museum in London.
This revelation has shed new light on the origins of these magnificent creatures ranging from Eoraptor and Herrerasaurus from Argentina, Saturnalia from southern Brazil, and Mbiresaurus from Zimbabwe.
“While earlier research has focused on southern South America and southern Africa as the area of origin of the dinosaurs, based on where their fossils first appear, we suggest that significant gaps in the fossil record – particularly in regions that today include the Sahara desert and the Amazon rainforest – may hold the potential to reveal where the earliest dinosaurs were living,” Heath explained.
In their new modeling, researchers propose a hypothesis that in the earliest days, dinosaurs were far less numerous than their reptilian relatives, which included the ancestors of crocodiles, the pseudosuchians—a diverse group featuring massive species reaching lengths of up to 10 meters—and pterosaurs, the pioneers of powered flight, whose wingspan rivaled the size of modern fighter jets.
Contrary to popular belief, early dinosaurs were modest in size, comparable to chickens or dogs rather than giants like Diplodocus. They were bipedal, walking on two legs, and likely omnivorous in their diet but gradually they rose to prominence following a series of volcanic eruptions 201 million years ago, which decimated many competing reptile species, the researchers wrote in their abstract.
The research further indicates that dinosaurs and other reptiles likely originated in low-latitude regions of Gondwana and expanded northward into Laurasia, the supercontinent that would later fracture into Europe, Asia, and North America. Citing the geographical positioning of fossil discoveries, they sketched out a midpoint between the earliest dinosaur remains found in southern Gondwana and fossils of their close relatives unearthed farther north in Laurasia.
READ: De-extinction? Plans to revive Tasmanian tiger triggers debate (August 20, 2022)
“Our results suggest early dinosaurs may have been well adapted to hot and arid environments. Out of the three main dinosaur groups, one group, sauropods, which includes the Brontosaurus and the Diplodocus, seemed to retain their preference for a warm climate, keeping to Earth’s lower latitudes,” said Senior Author and Professor Philip Mannion of UCL Earth Sciences.
“Evidence suggests the other two groups, theropods and ornithischians, may have developed the ability to generate their own body heat some millions of years later in the Jurassic period, allowing them to thrive in colder regions, including the poles,” he explained.