Key takeaways:

• Dinosaurs may have originated in low-latitude regions of Gondwana, which includes parts of modern-day Africa and South America.
• The earliest known dinosaur fossils date back approximately 230 million years, suggesting a lengthier prior evolutionary history.
• Geological research indicates that these areas during the Triassic Period were warmer and arid, contrasting previous beliefs about the dinosaurs' environmental conditions.
• The findings highlight significant gaps in the fossil record and the challenges faced by researchers in accessing and studying these regions.

Recent research has brought new insights into the origins of dinosaurs, suggesting they may have evolved in the equatorial regions of what are now Africa and South America. The findings, presented by a team from University College London and published in Current Biology, indicate that these prehistoric creatures likely emerged in areas that now encompass the Sahara Desert and the Amazon rainforest, regions that were once united as part of the supercontinent Gondwana.

Lead researcher Joel Heath explained that the earliest-known dinosaur fossils, which are dated to about 230 million years ago, were excavated primarily from locations such as Argentina, Brazil, and Zimbabwe. However, the evolutionary relationships among these early forms suggest that dinosaurs had been evolving for millions of years prior to their first appearance in the fossil record, as emphasized in findings from both Reuters and Newsweek.

The research team conducted modeling studies to establish hypotheses regarding where dinosaurs first originated, highlighting the significance of environmental conditions at the time. They found that these equatorial regions were inhospitable compared to the previously considered milder habitats of southern South America and southern Africa. Specifically, Heath noted that the region likely featured hot, dry deserts and savannah-like habitats, as well as a variety of ecological niches.

The scarcity of fossils in these regions is a considerable challenge for paleontologists, with dense forests and vast deserts complicating exploratory efforts. Researchers surmise that although no dinosaur fossils have been unearthed in these areas, it could be due to a lack of suitable rock formations rather than a lack of existence.

Dinosaurs are distinguished by unique skeletal traits, such as their upright stance with legs positioned directly beneath their bodies. This evolutionary adaptation allowed them to be agile and efficient in locomotion, setting them apart from their sprawling reptilian relatives. Early dinosaurs, such as Herrerasaurus and Eoraptor, exhibit various traits suggesting they adapted orders of magnitude to their environments, leading up to their diversification into the dominant terrestrial vertebrates they became by the late Triassic period.

Heath concluded that early dinosaurs were small and lived in the shadows of larger reptiles, including the ancestors of modern crocodiles. However, by approximately 201 million years ago, significant extinction events allowed dinosaurs to rise to ecological prominence.

As the findings develop, they offer profound implications regarding how dinosaurs adapted to their environments and how their evolutionary pathways diverged leading into the Jurassic period, when adaptations such as endothermy appeared, allowing them to thrive in varied climates.

For further details on this exciting discovery in paleobiology, visit SCMP.