Seventeen fossilised footprints preserved in a 35-centimetre-wide slab of red sandstone from southeastern Australia have upended the evolutionary timeline of land-dwelling vertebrates. Dated to between 359 and 350 million years ago, these prints are now the world’s oldest known reptile footprints—predating previous evidence by 35 million years.
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Found on the banks of the Broken River near Mansfield, Victoria, the footprints were identified by an international team of paleontologists led by Per Ahlberg of Sweden’s Uppsala University. The discovery, published in Nature, reveals that amniotes—a vertebrate group that includes reptiles, birds and mammals—appeared much earlier than previously thought.
Clawed Feet on Ancient Riverbanks
The footprints show hallmark reptilian features: long toes ending in sharp, curved claws. No tail or body drag marks were found, suggesting the animals walked fully upright on land. Each footprint measures around 3–4 centimetres, and the animals are estimated to have been about 60–80 centimetres long, with a body shape similar to a modern lizard.
“Only animals fully adapted to land ever evolved claws,” Ahlberg explained. “These are walking animals—true land vertebrates.” Crucially, claws are absent in amphibians and fish, indicating the creature was an early amniote rather than a transitional semi-aquatic form. This means the evolutionary step from water to fully terrestrial life happened much faster than previously believed.
From Raindrops to Reptiles
The sandstone slab provides a rare window into a single day 355 million years ago. One reptile walked across a muddy riverbank before a light rain obscured part of its tracks. Later, two more reptiles crossed the area in the opposite direction. Raindrop impressions and sediment helped preserve this moment in exceptional detail.
The area, then part of the southern supercontinent Gondwana, was hot and tropical, covered in dense forests and home to large freshwater fish. Today, the fossilised trackways stand as silent testimony to a key chapter in Earth’s evolutionary history.
Shifting the Origin Story
Previously, the oldest known reptile evidence came from 318-million-year-old fossils in Canada, and 328-million-year-old footprints in Poland. This Australian find pushes the timeline back into the early Carboniferous Period, forcing scientists to reconsider long-standing theories about when and where modern land vertebrates first evolved.
Genetic analyses had already hinted that the split between amphibians and amniotes might date back to the late Devonian, as far as 380 million years ago. This new evidence supports that theory—and raises the possibility that early amniotes may have originated in Gondwana, not Euramerica as traditionally thought.
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Until now, nearly all early tetrapod fossils had come from North America and Europe. The Gondwana fossil record has been sparse, with few examples from the Devonian or early Carboniferous. This makes the Mansfield slab even more significant—it suggests a rich, overlooked history of early tetrapods in the southern hemisphere. “This find changes the game,” said co-author John Long of Flinders University. “We may have been looking for the origins of reptiles in the wrong place all along.”