A groundbreaking fossil find in Australia’s Mansfield district has revealed that reptiles may have first walked the Earth up to 40 million years earlier than previously thought. Preserved trackways, dated to around 350 million years ago during the early Carboniferous period, show clear signs of clawed feet—suggesting the presence of early amniotes, the group that includes reptiles, birds, and mammals.
The international research team, led by Flinders University palaeontologist Professor John Long, published their findings today in the journal Nature. “This is the oldest evidence in the world of reptile-like animals walking around on land,” Long said. “It pushes their evolution back by 35 to 40 million years.”
Rewriting the Evolutionary Timeline
Previously, the oldest body fossils of crown-group amniotes were thought to date to about 318 million years ago, while the oldest tetrapod trackways were from around 353 million years ago. This new discovery, however, shows reptile-like creatures walking on land at least 350 million years ago—far earlier than established records.
The fossil tracks were found in Victoria’s Mansfield district by local fossil enthusiasts Craig Eury and John Eason. One trackway stood out, showing a distinct hooked claw—strong evidence of an amniote rather than an amphibian. “It was amazing how crystal clear the trackways are on the rock slab,” said Professor Long.
Gondwana, Not the North, May Be the Cradle of Reptiles
The find challenges the long-held view that early amniotes originated in the Northern Hemisphere. Instead, the evidence now points to Gondwana—the ancient southern supercontinent that included Australia—as a possible birthplace of reptiles. This has profound implications for understanding the global story of tetrapod evolution.
Professor Long and his team were able to date the fossil-bearing rocks by comparing the fish fossils found in the same layers with those from other well-dated locations around the world, confirming an age of around 350 million years.
High-Tech Tools Reveal Ancient Behaviour
Digital scans of the fossil footprints, created by Dr Alice Clement and analysed with Professor Per Erik Ahlberg’s team at Uppsala University in Sweden, provided highly detailed models of the trackways. Heatmaps generated by Dr Aaron Camens further clarified how the animal moved.
“A skeleton can tell us only so much,” said Dr Camens. “But a trackway actually records behaviour—it shows us how this animal was walking.”
Australia’s Growing Palaeontological Significance
The Mansfield district has long been a source of ancient fossil fish and sharks, but this is the first time evidence of land-walking tetrapods has been uncovered. The discovery underscores the untapped fossil potential of Australia and Gondwana.
Dr Jillian Garvey of La Trobe University, who has studied the Mansfield basin for over 20 years, emphasised the broader importance of the find. “This discovery rewrites this part of evolutionary history,” she said. “It indicates there is so much that has happened in Australia and Gondwana that we are still yet to uncover.”
A Fossil Find Decades in the Making
Professor Long’s connection to the area dates back to his PhD work in the 1980s. “Many had searched for such trackways, but never found them—until this slab arrived in our laboratory,” he said. “We sensed we were onto something big—even though we had no idea just how big.”
With this discovery, Australia emerges as a key site in understanding how vertebrates transitioned from water to land, and how early reptiles began their journey toward dominating Earth’s ecosystems.
