New research challenges long-held beliefs about dinosaur origins, suggesting they first emerged in equatorial Gondwana.

The Surprising Origins of Dinosaurs: Tracing Their Beginnings in Gondwana


New research challenges long-held beliefs about dinosaur origins, suggesting they first emerged in equatorial Gondwana. Discover how this reshapes our understanding of their evolution.


Unraveling the Mystery of Dinosaur Origins

For millions of years, dinosaurs reigned supreme over Earth’s land ecosystems, evolving into a breathtaking array of forms—from the colossal plant-eating Argentinosaurus to the fearsome Tyrannosaurus rex and the bizarre, clawed Therizinosaurus. Yet, despite decades of research, the precise location and timeline of their emergence remain one of paleontology’s most enduring puzzles. Now, a new study proposes an unexpected birthplace for these ancient creatures, reshaping our understanding of their early history.

A New Hypothesis on Dinosaur Beginnings

Paleontologists have long debated where dinosaurs first appeared. The latest research suggests they may have originated in regions that now encompass the modern-day Sahara Desert and the Amazon Rainforest. This conclusion stems from a combination of fossil evidence, evolutionary analysis, and an understanding of Earth’s prehistoric geography during the Triassic Period. At the time, the continents were united as a massive landmass known as Pangaea, with dinosaurs emerging in its southern region—Gondwana.
“Our findings suggest that the earliest dinosaurs likely evolved in low-latitude areas of Gondwana, near the equator,” explains Joel Heath, a paleontology doctoral researcher at University College London and the Natural History Museum in London. Heath is the lead author of a groundbreaking study published in Current Biology. “Today, these regions correspond to parts of northern South America and northern Africa.”

Ancient Fossils and Evolutionary Clues

The fossil record offers tantalizing glimpses into the early history of dinosaurs. Some of the oldest known specimens, dating back roughly 230 million years, include Eoraptor and Herrerasaurus from Argentina, Saturnalia from Brazil, and Mbiresaurus from Zimbabwe. While these creatures display defining dinosaurian traits, their differences hint at millions of years of prior evolution that remain undiscovered.
Previous research focused on southern South America and Africa as the likely cradles of dinosaur evolution due to the prevalence of early fossils found in those regions. However, Heath and his team argue that major gaps in the fossil record—particularly in the areas now covered by the Sahara and Amazon—suggest an even earlier origin yet to be uncovered. The challenge lies in the sheer inaccessibility of these regions, where dense forests and vast deserts make paleontological exploration difficult.

Dinosaurs in a Harsh World

Scientists estimate that dinosaurs emerged between 245 and 230 million years ago in an environment vastly different from today’s world. The equatorial regions of Gondwana were characterized by extreme heat and arid conditions, with a landscape comprising deserts, savannah-like habitats, and seasonal wildfires. Until recently, many believed that dinosaurs could not have thrived in such inhospitable settings.
“Our study suggests that dinosaurs were more adaptable than previously thought, capable of surviving in hot, dry environments that were once assumed to be unsuitable for them,” Heath explains. The scarcity of fossils from this time and region could be due to unfavorable conditions for fossilization or the simple fact that paleontologists have yet to unearth them.

The Rise of Dinosaurs After Earth’s Biggest Extinction

Dinosaurs evolved from earlier reptiles in the aftermath of a catastrophic mass extinction event 252 million years ago, at the end of the Permian Period. This global disaster, triggered by intense volcanic activity, wiped out an estimated 90% of Earth’s species, clearing the way for new forms of life to rise.
What set dinosaurs apart from their ancestors was a suite of unique skeletal adaptations. “Dinosaurs had upright limbs positioned beneath their bodies, unlike other reptiles, which had sprawling postures. This allowed for more efficient movement and greater agility,” Heath notes. Additionally, their specialized hips and diverse dental structures gave them an evolutionary edge, enabling them to adapt to different diets and ecological niches.
Early dinosaurs varied greatly in size and function. For instance, Herrerasaurus was a six-meter-long predator, while Eoraptor was a much smaller, omnivorous creature. These evolutionary advancements did not happen overnight; rather, they developed gradually over millions of years. However, a lack of transitional fossils means much of their evolutionary history remains an enigma.

Hunting for the Missing Links

One of the most intriguing discoveries hinting at the earliest dinosaurs is Nyasasaurus, a bipedal reptile from Tanzania. Estimated to be around 240–245 million years old, it is known only from fragmentary fossils, but it may represent a crucial transitional form bridging the gap between early reptiles and true dinosaurs.
At the time of their emergence, dinosaurs were far from the dominant creatures they would later become. They initially shared their world with a variety of formidable competitors, including giant terrestrial crocodile relatives and elephant-sized herbivores distantly related to mammals. For much of the Triassic, dinosaurs played a secondary role in ecosystems dominated by these other creatures.

How Dinosaurs Rose to Dominance

Everything changed around 201 million years ago when another mass extinction event reshaped Earth’s biodiversity. This event believed to be caused by massive volcanic eruptions and climate shifts, wiped out many of the dinosaurs’ rivals. With their superior agility, adaptability, and efficient movement, dinosaurs quickly expanded into vacant ecological roles, rising to become the dominant terrestrial vertebrates for the next 135 million years.
“Dinosaurs started small, existing in the shadows of larger, more dominant species,” Heath explains. “But when their competitors were wiped out, they seized the opportunity and diversified rapidly.”

The Search Continues

Despite these fascinating insights, many questions about dinosaur origins remain unanswered. Could even older fossils lie buried beneath the dense forests of the Amazon or the shifting sands of the Sahara? Advances in technology, such as remote sensing and AI-assisted fossil detection, may one day help paleontologists uncover these long-lost secrets.
For now, the study by Heath and his colleagues offers a compelling new perspective on how and where dinosaurs first emerged. By challenging long-held assumptions and highlighting unexplored fossil gaps, this research brings us one step closer to solving one of paleontology’s greatest mysteries.
The quest to uncover the origins of dinosaurs continues to evolve, with each discovery rewriting what we thought we knew. By looking beyond traditional fossil sites and considering new geological and evolutionary perspectives, scientists are piecing together the remarkable story of how these creatures first took their place in Earth’s history. As new excavations and technological advancements emerge, the mystery of dinosaur beginnings may soon be fully unveiled.

Source:  (Reuters)

 

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