Bombshell discovery of 'earliest footprints ever' completely rewrites theory of evolution

Scientists are hailing the discovery of the earliest reptile footprints, dating back a staggering 355 million years, as a potential game-changer for our understanding of evolution.

Unearthed by two keen amateur palaeontologists in Australia, the sandstone slab bears impressively preserved footprints featuring long-toed feet complete with "distinct" claw impressions at the tips.

These footprints mark the oldest known evidence of clawed feet, as highlighted in a groundbreaking study recently published in the esteemed journal Nature.

Uppsala University's Professor Per Ahlberg, leading the study, expressed his astonishment: "I'm stunned."

He further explained the significant implications of the find: "A single track-bearing slab, which one person can lift, calls into question everything we thought we knew about when modern tetrapods evolved."

The fascinating evolutionary journey from fish venturing out of water to their descendants branching into ancestors of today's amphibians and amniotes—a group including reptiles, birds, and mammals—has seemingly been thrown into disarray.

Previously it was understood that the first tetrapods came about during the Devonian period, with their modern descendents emerging later in the following Carboniferous period.

Considering that the earliest fossils of amniotes were dated to the late Carboniferous, approximately 320 million years ago, this new find could significantly push back the timeline for the emergence of modern tetrapod groups.

Scientists have been left gobsmacked by a groundbreaking discovery down under, which suggests that the evolutionary split between amphibians and amniotes – the 'tetrapod crown-group node' – occurred much earlier than previously thought, around 355 million years ago in the earliest Carboniferous period.

Previously, the Devonian period was considered the era of primitive fish-like tetrapods and intermediary "fishapods" like Tiktaalik.

However, an ancient sandstone slab unearthed in Australia has turned scientific understanding on its head.

Co-author Dr Grzegorz Niedźwiedzki from Uppsala University expressed his astonishment: "When I saw this specimen for the first time, I was very surprised, after just a few seconds I noticed that there were clearly preserved claw marks."

Prof Ahlberg added: "Claws are present in all early amniotes, but almost never in other groups of tetrapods."

He further explained: "The combination of the claw scratches and the shape of the feet suggests that the track maker was a primitive reptile."

This revelation could mean that reptiles, and therefore all amniotes, originated a staggering 35 million years earlier than the current consensus indicates.

The study also cites additional evidence from newly discovered fossil reptile footprints in Poland, which, while not as ancient as the Australian find, are still significantly older than any known before.

This adjustment in the timeline of reptile origins is set to revolutionise our understanding of the entire evolutionary history of tetrapods.

The research team, delving into the origins of tetrapods, suggests that these four-limbed vertebrates predate the earliest amniotes, with their study pointing to a much older lineage than previously thought.

Prof Ahlberg remarked: "It's all about the relative length of different branches in the tree.

"In a family tree based on DNA data from living animals, branches will have different lengths reflecting the number of genetic changes along each branch segment.

"This does not depend on fossils, so it's really helpful for studying phases of evolution with a poor fossil record."

Their innovative approach, which meshes DNA branch lengths with established fossil timelines, hints that the tetrapod crown group node harks back to the Devonian era, around the time of Tiktaalik, suggesting an unexpected diversity of advanced tetrapods coexisted with the primitive 'fishapods'.

Prof Ahlberg revealed: "The Australian footprint slab is about 50 centimetres across, and at present it represents the entire fossil record of tetrapods from the earliest Carboniferous of Gondwana - a gigantic supercontinent comprising Africa, South America, Antarctica, Australia and India.

"Who knows what else lived there?".

Dr Niedźwiedzki enthused: "The most interesting discoveries are yet to come and that there is still much to be found in the field.

"These footprints from Australia are just one example of this."