Scientists Say Dinosaurs Came From The Sahara And Amazon, Meaning There Are Fossils Out There Just Waiting To Be Discovered
The earliest dinosaurs may have emerged in the Amazon and other regions of South America and Africa—and their remains might just be waiting to be discovered.
Currently, the oldest known dinosaur fossils date back about 230 million years. They were found further south in places like Argentina, Brazil, and Zimbabwe.
However, the differences between these fossils indicate that dinosaurs had already been evolving for a while. Therefore, they must have originated millions of years earlier.
In a new study, researchers accounted for gaps in the fossil record. They concluded that the earliest dinosaurs likely appeared in a hot equatorial region in the supercontinent Gondwana, an area of land that includes what is now known as the Amazon, Congo basin, and Sahara Desert.
“Dinosaurs are well-studied, but we still don’t really know where they came from. The fossil record has such large gaps that it can’t be taken at face value,” said Joel Heath, the lead author of the study from the University College London.
“Our modeling suggests that the earliest dinosaurs might have originated in western, low-latitude Gondwana. This is a hotter and drier environment than previously thought, made up of desert- and savanna-like areas.”
To date, no dinosaur fossils have been found in the regions of South America and Africa that once formed part of the Gondwana. But perhaps researchers just haven’t come across the right rocks yet.
The earliest known dinosaurs are Eoraptor, Herrerasaurus, Eodromaeus, and Coelophysis. In the beginning, early dinosaurs were vastly outnumbered by their reptile relatives, which included the ancestors of crocodiles, pseudosuchians, and pterosaurs.
The earliest dinosaurs were also significantly smaller compared to their descendants. They were more like the size of a dog or a chicken.
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They walked on two legs and were believed to be omnivores. After volcanic eruptions wiped out their reptile relatives 201 million years ago, dinosaurs became dominant.
The findings indicate that dinosaurs and other reptiles may have originated in low-latitude Gondwana before spreading out to southern Gondwana and Laurasia, the neighboring northern supercontinent that later split into Europe, Asia, and North America.
This origin is a midpoint between where the earliest dinosaurs have been found and where fossils of their close relatives have been identified to the north in Laurasia.
“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 Philip Mannion, the senior author of the study.
The other two groups, theropods and ornithischians, possibly developed the ability to generate body heat millions of years later, sometime in the Jurassic period, allowing them to survive in colder regions.
The details of the study were published in the journal Current Biology.
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