Paleontologists have uncovered fossilized tracks of reptile-like creatures from the early Carboniferous Tonan period, approximately 355 million years ago, within the snow plain formation in Victoria, Australia. This discovery indicates that such animals originated from Gondwana, where Australia was centrally located.
Artist’s impression of early reptile track makers from 355 million years ago. Image credit: Martin Ambrozik.
Tetrapods evolved from a group of fish that transitioned from aquatic to terrestrial life around 390 million years ago during the Devonian period.
These ancestral beings are the forebears of all modern vertebrates inhabiting land, including amphibians and various mammals, reptiles, and birds.
The oldest known amniotic fossils previously discovered date back to the late Carboniferous period, roughly 320 million years ago.
The findings from this 355 million-year-old snow plains slab, found by two amateur paleontologists, reveal that reptiles were already present 35 million years earlier than previously thought, at the dawn of the Carboniferous.
“Upon recognizing this, I understood that we had the oldest evidence globally of animals akin to reptiles, pushing back the evolutionary record by at least 35 million years beyond prior findings in the Northern Hemisphere,” stated Professor John Long from Flinders University.
“The fossilized tracks uncovered in the Mansfield region of northern Victoria, Australia, were created by creatures resembling small, agile, Goanna-like animals.”
A slab containing 355 million-year-old tracks from Australia’s Snowy Plains formation. Image credit: Long et al., doi: 10.1038/s41586-025-08884-5.
“When I initially encountered this specimen, I was astounded. Just seconds later, I noticed that the nail impressions were remarkably preserved,” said Dr. Grzegorz Niedwiedzki, a researcher at Uppsala University.
“Nails are characteristic of all early amniotic species but are absent in other quadruped lineages,” added Per Erik Ahlberg, a professor at Uppsala University.
“The combination of nail marks and foot shapes suggests that the track maker was a primitive reptile.”
According to the research team, this discovery profoundly impacts the understanding of early tetrapod evolution.
Although all stem tetrapods and stem amniotes must have emerged during the Devonian period, evidence suggests that tetrapod evolution progressed significantly faster than previously believed, with far fewer Devonian tetrapods than assumed.
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“Skeletons can reveal much about an animal’s capabilities, but trackways capture behavior and illustrate how the animal functioned,” explained Dr. Alice Clement from Flinders University.
“This new fossilized trackway we examined dates from the early Carboniferous, making accurate age identification crucial. We achieved this by comparing the various fish fauna in these rocks to similar morphotypes found in well-dated sedimentary layers from across the globe, providing a timeline constraint of approximately 10 million years.”
“This finding redefines a segment of evolutionary history,” remarked Dr. Gillian Garvey from La Trobe University.
“Much has occurred in Australia and Gondwana, indicating that the narrative is still unfolding.”
The findings are detailed in a paper published in the journal Nature.
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Ja Long et al. Early amniote tracks revise the timeline of tetrapod evolution. Nature published online on May 14th, 2025. doi:10.1038/s41586-025-08884-5
Source: www.sci.news
