Reptile ancestors appeared 40 million years earlier than we thought

Fossil footprints from the ancient Carboniferous Period have caused a stir among paleontologists worldwide. These tracks suggest reptiles roamed Earth far earlier than anyone suspected.

Researchers uncovered reptile-like footprints in northern Victoria, Australia, and matched them to the era that started around 359 million years ago.

According to Professor John Long from Flinders University, these imprints challenge the traditional view of reptile evolution.

Footprints of reptile ancestors

According to the experts, the tracks suggest that these animals may have appeared roughly 350 million years ago. That date pushes them back to 40 million years earlier than what was previously recorded.

One set of partial prints had distinct claw marks, hinting that these creatures were true reptiles rather than amphibians. Another set showed a smaller front foot and a larger hind foot, which is typical of land-walking vertebrates.

Reptile origins in Gondwana

Scientists have long studied the southern supercontinent Gondwana, where many early tetrapods left behind their skeletons and tracks. This find in Victoria adds weight to the idea that pivotal evolutionary steps began in these territories.

At the time, Australia formed a central piece of this landmass. Warmer climates may have played a role in encouraging new adaptations among reptile forerunners.

New timeline of reptile evolution

Paleontologists analyze footprints to piece together how ancient animals moved. A set of clawed toes can reveal whether a creature was an amphibian or a reptile.

“This pushes back the likely origin of crown-group amniotes by at least 35-40 million years,” said Professor John Long. The research highlights how vital footprints can be for revealing new timelines.

Reptiles are part of the amniote group, which includes birds and mammals. The discovery of claw marks in these fossil tracks implies full independence from watery environments, which is a characteristic of reptiles.

Many scientists once assumed that amniotes emerged in the Northern Hemisphere. These footprints raise questions about when and where some of the earliest reptiles spread across ancient landscapes.

Shifting landscapes and animal diversity

Researchers plan to explore other parts of Victoria for more trace fossils that could fill gaps in the record. They hope future finds will clarify how these animals became adapted for dry land.

Unearthing additional trackways may add to our understanding of how reptiles branched off from amphibians. Each new print can reveal details about posture, movement, and survival tactics.

The Carboniferous Period stretched from about 359 million to 299 million years ago. It featured vast swampy forests, giant insects, and a rise in atmospheric oxygen levels.

Land masses were arranged differently than they are today. Some scientists believe shifting coastlines created niches that spurred new adaptations.

Habitats of reptile ancestors

Some reptile ancestors likely ventured onto stable ground while others stayed near water. Traces of this transition remain scarce, so every fossil footprint matters.

Even a single impression can show scientists how early amniotes balanced their weight or held their tails. The shape, depth, and spacing can reveal clues about speed or range of motion.

A single fossil slab from Victoria has opened up this debate about reptile origins. Researchers suggest it is significant to re-check older formations in case more reptile evidence has been overlooked.

Professor Long and his team emphasize the need for more fieldwork to confirm whether reptiles appeared across multiple regions at around the same time. They believe this discovery highlights how a single trackway can reshape our ideas about early amniotes.

Seeking more reptile footprints

Future excavations may uncover more footprints from the early stages of reptile evolution. That could bring clarity to how quickly these animals adapted to life away from water.

Technological advancements like high-resolution scans can make it easier to analyze the details of each print. Insights like these help paleontologists reconstruct entire ecosystems from a few traces left in stone.

Footprint analysis often involves laser scanning to capture 3D shapes. These scans can highlight fine ridges that point to muscle strength or toe flexibility.

Traces of skin patterns, though rare, can also indicate the texture of scales. Each layer of mud or sand holds hints about local conditions.

Early land adaptation of reptiles

Before amniotes, vertebrates such as fish and amphibians still needed water for reproduction. Over time, eggs with protective membranes evolved and these allowed animals such as reptiles to venture inland.

That transition set the stage for reptiles, birds, and mammals to diversify into countless forms. These footprints mark a link in that long chain.

Researchers compare new prints to known trackways from synapsids and early amphibians. Key distinctions include toe curvature and the presence of claws.

Synapsids, which later led to mammals, often left broader footprints with different digit spacing. Reptile-like tracks, on the other hand, typically show sharper claw impressions.

Ancient footprints of reptile ancestors

These ancient footprints connect modern wildlife to ancestors that once explored muddy banks. Each imprint brings a sense of wonder about how life took shape on land.

Understanding those steps may also shed light on broader evolutionary processes. After all, reptile success paved the way for the future rise of dinosaurs and beyond.

Scientists emphasize that no single discovery stands alone. Footprints, bones, and environmental data must all be pieced together to form a coherent story.

Though incomplete, this record keeps expanding thanks to fresh finds in unexpected places. Each new track offers a glimpse into a time of rapid evolutionary change.

The study is published in the journal Nature.

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