Earliest Carboniferous clawed tracks reported from Australia

Long et al 2025 brings us tracks from the Early Cretaceous of Australia.
From the abstract: “The known fossil record of crown-group amniotes begins in the late Carboniferous with the sauropsid trackmaker Notalacerta and the sauropsid body fossil Hylonomus.”

Several problems here.
Amniota is a junior synonym for Reptilia = Silvanerpeton (Fig 1) and all of its ancestors in the large reptile tree (LRT, 2338 taxa,, which minimizes taxon exclusion by virtue of its long list of taxa. Silvanerpeton is known the Viséan (Early Carboniferous, Fig 2). It is the earliest known reptile based on the last common ancestor method. A proximal outgroup taxon is Tulerpeton (Fig 1) from the Late Devonian (Fig 2). The traditional clade ‘Sauropsida’ is not recovered by the LRT.

“The earliest body fossils of crown-group tetrapods are mid-Carboniferous, and the oldest trackways are early Carboniferous^5,6,7. This suggests that the tetrapod crown group originated in the earliest Carboniferous (early Tournaisian), with the amniote crown group appearing in the early part of the late Carboniferous.”

Discussions of crown groups are vague to meaningless in ichnology. Even so, tetrapods are known from Middle Devonian trackways, according to the authors (Fig 2).

“Here we present new trackway data from Australia that challenge this widely accepted timeline. A track-bearing slab from the Snowy Plains Formation of Victoria, Taungurung Country, securely dated to the early Tournaisian, shows footprints from a crown-group amniote with clawed feet, most probably a primitive sauropsid.”

Several problems here.
Again, ‘Sauropsida’ is not recovered by the LRT. Rather the first dichotomy, revealed over a decade ago, splits Lepidosaurmorpha from Archosauromorpha. Claws don’t make tracks belong to crown-group amniotes, even though Silvanerpeton had scales and claws. So did Tulerpeton (Fig 1).

Always use the last common ancestor method in taxonomy. Don’t rely on a single or even a dozen traits. We call that mistake, “Pulling a Larry Martin” because the late professor tested students with this trick = method.

“This pushes back the likely origin of crown-group amniotes by at least 35–40 million years.’

Let’s get specific. Figure 2 (Fig 4 of Long et al) pinpoints the featured amniote tracks at 356 mya, between clawed Tulerpeton and clawed Silvanerpeton (Fig 1) in the LRT.

“We also extend the range of Notalacerta into the early Carboniferous. The Australian tracks indicate that the amniote crown-group node cannot be much younger than the Devonian/Carboniferous boundary, and that the tetrapod crown-group node must be located deep within the Devonian; an estimate based on molecular-tree branch lengths suggests an approximate age of early Frasnian for the latter.”

Try not to use molecules in paleontology.
Deep time (due to viruses?) plays havoc with molecules.
So much better to use fossils in paleontology. After all, fossil = paleontology!

“The implications for the early evolution of tetrapods are profound; all stem-tetrapod and stem-amniote lineages must have originated during the Devonian.”

Not so “profound”. We’ve known this for several years at present (Fig 2).

“It seems that tetrapod evolution proceeded much faster, and the Devonian tetrapod record is much less complete, than has been thought.”

Again, why bring up tetrapods here? That’s off topic relative to the headline.
The answer is: the authors are attempting to gauge the time between the first fingers (Fig 3) and the first amnion. Unfortunately one learns this only after reading the text, which also includes some discussion about lungfish, which lack fingers. More focus could have been brought to this wide-ranging paper about one set of reptile tracks.

The authors wrote,
“The origin of tetrapods, understood as an evolutionary and ecological phenomenon, was not a single event but a process that began with the acquisition of incipient terrestrial locomotory competence in the tetrapod stem group and ended with the emergence of the major crown-group clades, amphibians and amniotes.”

That’s a long way around to say, ‘the first time we see fingers and toes’ (Fig 3).

The authors mention Tulerpeton once,
“With the exception of Tulerpeton and Brittagnathus in the Devonian, and some possible
Devonian-grade tetrapods in the Tournaisian, all known Devonian tetrapods seem to represent a less crownward segment of the tetrapod stem than any post-Devonian forms.

Evidently the authors did not consider Tulerpeton important, despite its pertinent morphology (Fig 1) and chronology (Fig 2). Or was it omitted to make a better story?

Long et al don’t mention Silvanerpeton at all.
Lesson for today: build your cladogram with as many taxa as reasonable, so you are not surprised and dismayed by readers reporting the omission of the most pertinent taxa.

References
Long et al (7 co-authors) 2025. Earliest amniote tracks recalibrate the timeline of tetrapod evolution. Nature https://doi.org/10.1038/s41586-025-08884-5

Publicity from Phys.org

“Earliest reptile footprints rewrite the timeline of tetrapod evolution”
by Uppsala University

“New discoveries of fossil clawed footprints from Australia, published in Nature, push the origin of reptiles back in time by at least 35 million years and change the entire timeline for the origin of tetrapods (backboned land animals).“I’m stunned,” says Per Ahlberg of Uppsala University, who coordinated the study. “A single track-bearing slab, which one person can lift, calls into question everything we thought we knew about when modern tetrapods evolved.”

“I’m stunned,”
“calls into question everything we thought we knew”
Puffery goes hand-in-hand with publicity. Ignore it and keep reading.

“The story of the origin of tetrapods began with fishes leaving the water, and ended with the descendants of these first colonists on land diversifying into the ancestors of the modern amphibians and amniotes (the group that includes reptiles, birds and mammals).

The timeline of these events has seemed clear-cut: the first tetrapods evolved during the Devonian period and the earliest members of the modern groups appeared during the following Carboniferous period. The earliest amniote fossils are from the late Carboniferous, about 320 million years old.

See above for how out-of-date this is due to taxon exclusion.

This led researchers to conclude that the beginning of the evolutionary radiation of the modern groups, the point on the evolutionary tree where the ancestors of amphibians and amniotes separated (also known as the “tetrapod crown-group node”), lay in the earliest Carboniferous around 355 million years ago. The Devonian period was seen as inhabited by more primitive fish-like tetrapods and transitional “fishapods” such as Tiktaalik.

Again, who cares about the ‘crown group’? It relies on the vague chance survival of ‘living fossils’ like the tuatara or coelcanth.

A sandstone slab from the earliest Carboniferous of Australia, approximately 355 million years old, discovered by two amateur paleontologists who co-authored the study, changes all this. It carries well-preserved footprints of long-toed feet with distinct claw impressions at the tips. These are by far the earliest clawed footprints ever discovered.

See how accessible paleontology is? Sometimes amateurs are welcome! Other times, not so much. Depends if you find a fossil or if you find long-sought ancestors among fossils already poured over by academics.

“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,” says Grzegorz Niedźwiedzki of Uppsala University, co-author of the study.

“Claws are present in all early amniotes, but almost never in other groups of tetrapods,” adds Ahlberg. “The combination of the claw scratches and the shape of the feet suggests that the track maker was a primitive reptile.”

“Almost never” might be referring to the famous ‘clawed frog’ once available in pet shops and perhaps other clawed tetrapods, like Silvanerpeton (Fig 1), Eusuropleura and Gephyrostgeus (Fig 2), not mentioned in the text.

Again, relying on one trait is referred to as “Pulling a Larry Martin“. Stick with the last common ancestor method. It never fails, by definition, unless that taxon is omitted.

“New discoveries of fossil clawed footprints from Australia, published in Nature, push the origin of reptiles back in time by at least 35 million years and change the entire timeline for the origin of tetrapods (backboned land animals).”

Nice to see the ‘origin of reptiles’ is reported here, rather than the ‘origin of amniotes’ the junior synonym for reptiles in the LRT. Probably just a typo.

“If this interpretation is correct, it pushes the origin of reptiles, and thus amniotes as a whole, back by 35 million years to the earliest Carboniferous. Further support comes from new fossil reptile footprints from Poland, also presented in the study; not as old as those from Australia, but also substantially older than previous records.

“and thus amniotes” = doubling back on that earlier typo.

This recalibration of the origin of reptiles impacts the whole timeline of tetrapod evolution.

Are they confessing to a mistake of omission? See the Silvanerpeton story above.

The tetrapod crown-group node must be older than the earliest amniotes, because it is a deeper branching point in the tree, but how old exactly? The authors address this problem by combining data from fossils and modern DNA.

Better to just use more fossils. See the LRT for an example of this.

“It’s all about the relative length of different branches in the tree,” explains Ahlberg. “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.”

We’ve seen time and again how DNA recovers false positives. Avoid it.

Their analysis, overlaying branch lengths from DNA analyses onto the known fossil dates, indicates that the tetrapod crown group node lies far back in the Devonian, roughly contemporary with Tiktaalik.

Tiktaalik is 375 million years old, not that ‘far back in the Devonian’ which goes back another 44 million years.

This means that a diversity of advanced tetrapods existed at a time when, it has been thought, only transitional “fishapods” were dragging themselves around muddy shorelines and starting in a small way to explore the land. But perhaps that should not surprise us.

… like Tulerpeton (Fig 1). If this concept was important enough to mention in the publicity, why was Tulerpeton not given a paragraph or two in the text?

“The Australian footprint slab is about 50 cm across,” says Ahlberg, “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?”

Indeed. Fossils finds are rare pinpricks on the globe
from which the fossil record has been slowly building.

“The most interesting discoveries are yet to come and there is still much to be found in the field. These footprints from Australia are just one example of this,” says Niedźwiedzki.”

phys.org/news-earliest-reptile-footprints-rewrite-timeline

Source: https://pterosaurheresies.wordpress.com/2025/05/15/earliest-carboniferous-clawed-tracks-reported-from-australia/