A new study suggests the earliest dinosaur fossils may lie buried beneath the Amazon rainforest and the Sahara Desert, challenging long-held beliefs about the geographic origin of these ancient creatures.
According to research conducted by experts from University College London and published on January 26, 2025, the fossils we have discovered so far indicate dinosaurs were already diversifying long before the oldest known specimens appeared around 230 million years ago. This new investigation highlights the significant geographic gaps where fossil discoveries have largely been absent, especially around the equator.
Lead author Joel Heath, a PhD student at UCL, stated, "Dinosaurs are well studied, but we still don’t really know where they came from. The fossil record has such large gaps..." This observation implies our search for early dinosaur ancestors might have overlooked potentially fruitful areas.
The traditional belief held by paleontologists was centered around places like Argentina and Zimbabwe, where many dinosaur fossils have been found. Yet, this study indicates we might need to refocus our efforts on regions previously thought devoid of such remnants. Heath elaborates, "So far, no dinosaur fossils have been found...this might be because researchers haven’t stumbled across the right rocks yet, due to...inaccessibility and...a relative lack of research efforts."
The study employs sophisticated modeling techniques to identify regions likely to hold undiscovered dinosaur fossils, particularly within the equatorial supercontinent of Gondwana, which includes modern-day South America and parts of Africa.
This research posits Gondwana as the birth ground of the earliest dinosaurs, challenging previous assumptions of their origins. Heath’s work suggests these creatures thrived in hot, arid environments, akin to those of today’s deserts and savannahs. The team’s model accounts for significant gaps by treating untested regions not as devoid of evidence but as simply missing data points.
Referring to the modeling process, Heath remarked, "If dinosaurs did originate in equatorial Gondwana, their earliest ancestors could be buried beneath the rainforests of the Amazon or the sands of the Sahara..." This possibility fosters excitement for paleontologists who are eager to explore these unexplored territories.
Dinosaurs first emerged during the Late Triassic period, but during their early existence, they were just one group among many reptiles. Original dinosaurs were relatively small – about the size of chickens or dogs – and adapted to swiftly navigate their environment as hunters and scavengers. Over millions of years, they evolved from these more modest beginnings to rule the planet.
A dramatic turn for the dinosaurs came with the end-Triassic mass extinction, around 201 million years ago. This cataclysm created significant ecological shifts, allowing the surviving dinosaurs to diversify and dominate for the next 135 million years.
Co-author Philip Mannion noted, "The results suggest early dinosaurs may have been well adapted to hot and arid environments." Certain dinosaur groups, such as sauropods, preferred warm climates and remained at lower latitudes throughout their evolution, whereas other groups, like theropods, adapted to colder regions much later.
Despite these promising theories, direct fossil evidence from the Amazon or Sahara remains elusive. Future expeditions to these areas may yield discoveries pertinent to our comprehension of the origins of dinosaurs, as these regions represent some of the least-explored fossil sites on Earth.
The narrative of dinosaur origins, as outlined by this latest study published in the journal Current Biology, emphasizes the unexplored potential of these regions for yielding significant paleontological insights.
The true story of how dinosaurs came to dominate our planet might still be waiting to be uncovered beneath the dense canopies of the Amazon or the shifting sands of the Sahara, making the case for new frontiers and renewed focus in fossil research.