Scientists have discovered fossilized footprints in southeastern Australia that are approximately 355 million years old, forcing a major reevaluation of reptile evolution timelines. The ancient tracks, published in Nature, reveal the oldest known clawed tetrapod footprints, suggesting that primitive reptiles were already walking on land earlier than previously believed.
For decades, paleontologists believed that tetrapods evolved during the Devonian period as fish-like creatures adapted to terrestrial life. However, the new discovery disrupts this timeline, indicating that early reptiles or amniotes, a group including reptiles, birds, and mammals, were already present on land.
The footprints’ distinct long toes and claw marks suggest they were left by an early reptile or amniote. According to lead researcher Per Ahlberg, the discovery pushes back the divergence between reptiles and mammals, which previously occurred later than suggested by fossil records.
Claws are a crucial evolutionary marker, as early amphibians and transitional “fishapods” lacked them. The presence of claw marks on these footprints provides evidence that the creature was more advanced than other early tetrapods.
The discovery challenges existing assumptions about Tiktaalik, a transitional species between fish-like creatures and tetrapods. Instead, Tiktaalik appears to have coexisted with early amniotes, rather than being their direct ancestor.
By integrating fossil evidence with molecular data, researchers now believe the split between amniotes and amphibians occurred during the Devonian period, likely 35 million years earlier than assumed.
The discovery of these footprints represents the entire known fossil record of early Carboniferous tetrapods from Gondwana. Further paleontological fieldwork in Australia and other regions is crucial to uncover more fossils that could illuminate early amniote evolution.
As Ahlberg noted, “Who knows what else lived there?” The discovery highlights how much remains to be learned about the origins of terrestrial vertebrates and underscores the dynamic nature of the fossil record.
Source: https://dailygalaxy.com/2025/05/355-million-year-old-footprints6reptiles