Continental drift: The movement of mainlands on the planet Earth in different periods from 250 million years ago to resent. (Credit: Noiel on Shutterstock) Posted on 01/27/2025 10:45:56 AM PST by Red Badger
LONDON — The mystery of dinosaur origins has taken an unexpected turn toward the equator. While paleontologists have long searched southern regions for clues about where these magnificent creatures first evolved, new research suggests we may have been looking in the wrong latitude altogether. A new study indicates that the first dinosaurs may have emerged in Earth’s ancient tropics, forcing scientists to reconsider long-held theories about their origins.
For years, paleontologists believed dinosaurs originated in what is now southern South America and southern Africa, since the oldest unequivocal dinosaur fossils come from late Carnian rock formations (around 230 million years ago) in these regions. However, these earliest assemblages already show remarkable diversity in both anatomy and species variety, hinting at an even earlier evolutionary history that remains undiscovered.
“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,” explains lead author Joel Heath, a PhD student at University College London Earth Sciences and London’s Natural History Museum, in a statement.
The research team analyzed the distribution patterns of early dinosaurs and their close relatives using sophisticated computational models that account for gaps in fossil sampling across different regions. Their results, published in Current Biology, frequently support the emergence of dinosaurs in low-latitude regions of the ancient supercontinent Gondwana — essentially the tropical areas of what would become Africa and South America.
“Our modelling 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 savannah-like areas,” says Heath.
During this early period, dinosaurs were far from dominant. They shared their world with various reptilian cousins, including pseudosuchians — an abundant group containing species up to 10 meters long that were ancestors to modern crocodiles — and pterosaurs, the first animals to achieve powered flight. While their descendants would later grow to enormous sizes, the earliest dinosaurs were relatively small, comparable to modern chickens or dogs, walked on two legs, and were likely omnivorous.
Continental drift: The movement of mainlands on the planet Earth in different periods from 250 million years ago to resent. (Credit: Noiel on Shutterstock)
Most notably, the tropical origin hypothesis gained its strongest support when the researchers considered silesaurids (early dinosaur relatives) as primitive ornithischian dinosaurs. This placement helps explain a long-standing puzzle: why we don’t find any ornithischian dinosaur fossils before the Early Jurassic period, despite knowing the group must have existed earlier based on evolutionary relationships.
Modern tropical regions like northern Africa and the Amazon rainforest have yielded relatively few dinosaur fossils compared to temperate zones. “So far, no dinosaur fossils have been found in the regions of Africa and South America that once formed this part of Gondwana. However, this might be because researchers haven’t stumbled across the right rocks yet, due to a mix of inaccessibility and a relative lack of research efforts in these areas,” Heath explains.
The study indicates that the entire radiation of archosaurs likely occurred within low-latitude Gondwana following the devastating end-Permian mass extinction about 252 million years ago. From these tropical origins, different lineages then dispersed across Pangaea into various ecological and climatic zones during the Late Triassic period.
Professor Philip Mannion, senior author from UCL Earth Sciences, notes: “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.”
Understanding dinosaur origins requires not only examining where their fossils have been found but also considering where they haven’t been found, and why. This study suggests that the next breakthrough in dinosaur evolution might come not from new fossil discoveries, but from better understanding the biases and gaps in our current knowledge.
Paper Summary
Methodology
The research team constructed three different evolutionary trees reflecting competing hypotheses about early dinosaur relationships. They calibrated these trees against geological time using two different methods and incorporated information about potential geographic and climatic barriers to movement across ancient Pangaea. Crucially, they developed a novel approach to account for sampling biases in the fossil record by marking areas lacking any terrestrial vertebrate fossils as potentially containing undiscovered species rather than assuming definitive absence.
Results Dinosaurs became the dominant terrestrial vertebrates only after major volcanic eruptions eliminated many of their reptilian competitors around 201 million years ago. The modeling results suggest that both dinosaurs and other reptiles may have originated in low-latitude Gondwana before spreading outward to southern Gondwana and Laurasia, the northern supercontinent that later became Europe, Asia, and North America.
Limitations
The researchers acknowledge that their choice of geographic areas may introduce some bias due to size differences between regions. However, they argue that fossil preservation typically occurs in concentrated deposits regardless of region size, and sampling quality doesn’t necessarily correlate with area. The study also couldn’t fully account for relative sampling intensity in areas with some fossil discoveries versus those with many.
Discussion and Takeaways
This study demonstrates how accounting for gaps in the fossil record can dramatically change our understanding of evolutionary history. It suggests that many early dinosaur fossils may remain undiscovered in modern tropical regions due to a combination of natural and human factors. The research also highlights the importance of considering early dinosaur relatives like silesaurids when reconstructing their origins.
Funding & Disclosures
The research was funded by the London NERC DTP and supported by funding from the Royal Society and the Leverhulme Trust. The study is Paleobiology Database official publication number 513.
Publication Information
The study “Accounting for sampling heterogeneity suggests a low paleolatitude origin for dinosaurs” was published in Current Biology on March 10, 2025. Lead author Joel A. Heath conducted the research with colleagues from University College London and the Natural History Museum London.
I’ve often wondered what ‘evolutionary’ requisite necessitated the production of small short arms on a T-Rex and some of its cousins?
Lack of use causing the withering?
OR
Were they just a ‘work in progress’ and beginning to become larger?
Were they coming or going?
If they were going away, shouldn’t we find fossils of older T-Rex’s with longer arms?................
Thank you for posting the “It’s Aliens “ guy. This thread wouldn’t have been complete without him.
In what way is this report ‘shocking’?
It’s shocking in that we were STILL silly enough to check on click bait after all these years :)
The Gap Theory....
Should have checked Rexkjavik:
Looking forward to this say-so story.
I believe that’s when “ALL living things” were created. At least, according to THE Book.
Genesis 1:24
And God said, “Let the land produce living creatures according to their kinds: the livestock, the creatures that move along the ground, and the wild animals, each according to its kind.” And it was so. 25 God made the wild animals according to their kinds, the livestock according to their kinds, and all the creatures that move along the ground according to their kinds. And God saw that it was good.
26 Then God said, “Let us make mankind in our image, in our likeness, so that they may rule over the fish in the sea and the birds in the sky, over the livestock and all the wild animals,[a] and over all the creatures that move along the ground.”
27 So God created mankind in his own image,
in the image of God he created them;
male and female he created them.
28 God blessed them and said to them, “Be fruitful and increase in number; fill the earth and subdue it. Rule over the fish in the sea and the birds in the sky and over every living creature that moves on the ground.”
29 Then God said, “I give you every seed-bearing plant on the face of the whole earth and every tree that has fruit with seed in it. They will be yours for food. 30 And to all the beasts of the earth and all the birds in the sky and all the creatures that move along the ground—everything that has the breath of life in it—I give every green plant for food.” And it was so.
31 God saw all that he had made, and it was very good. And there was evening, and there was morning—the sixth day.
bigdaddy45 wrote:
No, but we apparently are positive the oceans will be boiling in about 20 years
Nope, it’s only about 6 years (6.3?) years left... it was 20 years about 14 years ago... Of course, it was 20 years in the 1980’s, too. Then in the 90’s. Then in the 2000’s. And then in the 2010’s, and now even in the middle of the 2020’s, it’s in 20 years.
Bookmark.
Thanks for the pings!
I'm a Little Dinosaur (Live) | 2:07
Jonathan Richman - Topic | 5.15K subscribers | 1,956 views | May 5, 2022
Things that make you wonder: If God didn’t create the Sun, Moon and stars until the fourth day, where did ‘the light’ come from on the first day?
The study indicates that the entire radiation of archosaurs likely occurred within low-latitude Gondwana following the devastating end-Permian mass extinction about 252 million years ago.
—
The clue of their origin is right in front of them. Dinosaurs arrived on a very large space ship which crashed, and causing “the devastating end-Permian mass extinction about 252 million years ago” which crash spilled them all over the landscape.
There were no illegals them to clean up the mess.
They came from PBS.
At least the Purple ones,.
Ask the captives at Area 51....they know.
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