Latest news with #PerAhlberg
The Print
18-05-2025
- Science
- The Print
Discovery of ancient ‘reptile' claw fossils kicks evolution's timeline back by over 35 million years
'I'm stunned,' Per Ahlberg from Uppsala University, who led the study, said in a media release . 'A single track-bearing slab, which one person can lift, calls into question everything we thought we knew about when modern tetrapods evolved.' A study published in Nature Wednesday dates the fossil tracks to be approximately 355 million years old. It pushes the origin of the species back by 35 to 40 million years from what was earlier thought to be the point when tetrapods evolved from a group of fish that left the sea. This has an implication on the history of human evolution given that we are direct descendants of these tetrapods. New Delhi: The discovery of ancient fossil footprints of claws in Australia have scientists across the world re-examining evolutionary times of land-based vertebrates. It was two amateur explorers who discovered the tracks on the banks of the Broken River in Taungurung Country, Victoria, and alerted paleontologists. They were preserved on the upper surface of a loose but fine-grained silty sandstone block. In the Nature study, the authors called it a 'demonstration of the value of citizen science.' Uppsala University's Ahlberg teamed up with paleontologists from Australia's Flinders University. 'Once we identified this, we realised this is the oldest evidence in the world of reptile-like animals walking around on land, and it pushes their evolution back by 35-to-40 million years older than the previous records in the Northern Hemisphere,' said Professor John Long of Flinders University in a press release. Their findings are threatening to upend our understanding of evolution of all tetrapods. Also Read: 47 yrs ago, this Indian-origin physicist asked Feynman a question. He hasn't looked back since When did the first tetrapods emerge? As the word suggests, tetrapods include all species that have 'four feet'. They are the first colonists on land and their origin began when fish transitioned from the oceans to adapt to life on land. They are the distant ancestors of all modern amphibians and amniotes that includes vertebrate animals like reptiles, birds and mammals, including humans. The oldest known tetrapods had primitive fish-like forms, and could barely move on land. The separation of amphibians and amniotes was so far believed to have begun at the start of the Carboniferous period, some 355 million years ago. This separation is known as the tetrapod crown group node. The new study changes what was previously known by suggesting that the separation dates back to the Devonian period, some 390 million years ago. '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,' according to the media release from Uppsala University. It's the claws that have generated much excitement within the scientific community. 'Claws are present in all early amniotes, but almost never in other groups of tetrapods,' said Ahlberg. 'The combination of the claw scratches and the shape of the feet suggests that the track maker was a primitive reptile.' The study also suggests that tetrapods originated in Gondwana, the southern supercontinent which Australia was a part of. It also included present-day South America, Africa, Arabia, Madagascar, India, and Antarctica. The researchers have also found new fossil reptile footprints from Poland, suggesting that tetrapods in the Euramerica—the supercontinent that formed during the Devonian period and included North America, Greenland, northern Europe, and Russia—also originated earlier than previously thought. So far, researchers have found only fossilised footprints and no fossil bones of ancient tetrapods, but if the new timelines are correct, the fossil footprints findings suggest that the evolution into land-based animals occurred not just earlier but also much quicker than initially thought. (Edited by Radifah Kabir) Also Read: Search for an Indian Carl Sagan is on. Science influencers are being trained in labs and likes
Observer
17-05-2025
- Science
- Observer
Ancient footprints from Australia reveal earliest-known reptile
Seventeen footprints preserved in a slab of sandstone discovered in southeastern Australia dating to about 355 million years ago are rewriting the history of the evolution of land vertebrates, showing that reptiles arose much earlier than previously known. The fossilized footprints, apparently made on a muddy ancient river bank, include two trackways plus one isolated print, all displaying hallmark features of reptile tracks including overall shape, toe length and associated claw marks, researchers said. They appear to have been left by a reptile with body dimensions similar to those of a lizard, they said. The footprints reveal that reptiles existed about 35 million years earlier than previously known, showing that the evolution of land vertebrates occurred more rapidly than had been thought. "So this is all quite radical stuff," said paleontologist Per Ahlberg of the University of Uppsala in Sweden, who led the study published on Wednesday in the journal Nature. The Australian footprints were preserved in a sandstone slab measuring about 14 inches (35 cm) across that was found on the banks of the Broken River near the town of Barjarg in the state of Victoria. The story of land vertebrates started with fish leaving the water, a milestone in the evolution of life on Earth. These animals were the first tetrapods - meaning "four feet" - and they were the forerunners of today's terrestrial vertebrates: amphibians, reptiles, mammals and birds. Footprints in Poland dating to about 390 million years ago represent the oldest fossil evidence for these first tetrapods, which lived an amphibious lifestyle. These creatures were the ancestors of all later land vertebrates. Their descendants split into two major lineages - one leading to today's amphibians and the other to the amniotes, a group spanning reptiles, mammals and birds. The amniotes, the first vertebrates to lay eggs on land and thus finally break free of the water, cleaved into two lineages, one leading to reptiles and the other to mammals. Birds evolved much later from reptile ancestors. The Australian footprints each are approximately 1-1.5 inches (3-4 cm) long. They appear to have been left by three individuals of the same reptile species, with no tail drag or body drag marks. No skeletal remains were found but the footprints offer some idea of what the reptile that made them looked like. "The feet are rather lizard-like in shape, and the distance between hip and shoulder appears to have been about 17 cm (6.7 inches). Of course we don't know anything about the shape of the head, the length of the neck or the length of the tail, but if we imagine lizard-like proportions the total length could have been in the region of 60 cm to 80 cm (24 to 32 inches)," Ahlberg said. "In terms of its overall appearance, 'lizard-like' is probably the best guess, because lizards are the group of living reptiles that have retained the closest approximation to the ancestral body form," Ahlberg added. The modest size of the earliest reptiles stands in contrast to some of their later descendants like the dinosaurs. This reptile probably was a predator because plant-eating did not appear until later in reptilian evolution. The bodies of herbivorous reptiles tend to be big and clunky, whereas this one evidently was lithe with long, slender toes, Ahlberg said. The researchers also described newly identified fossilized reptile footprints from Poland dating to 327 million years ago that broadly resemble those from Australia. Those also are older than the previous earliest-known evidence for reptiles - skeletal fossils from Canada of a lizard-like creature named Hylonomus dating to around 320 million years ago, as well as fossil footprints from about the same time. The reptile that left the Australian footprints lived during the Carboniferous Period, a time when global temperatures were similar to today's, with ice at Earth's poles but a warm equatorial region. Australia at the time formed part of the ancient supercontinent Gondwana and lay at the southern edge of the tropics. There were forests, partly composed of giant clubmoss trees. "The tracks were left near the water's edge of what was probably quite a large river, inhabited by a diversity of big fishes," Ahlberg said. —Reuters
Yahoo
15-05-2025
- Science
- Yahoo
Ancient reptile tracks rewrite when animals conquered land
After a brief rain in part of the ancient supercontinent of Gondwana 350 million years ago, a reptile pressed its small claws into the still-wet ground. Its tracks, which have been discovered in Australia, mean it is the oldest-known vertebrate animal to have permanently abandoned the oceans for dry land, a study suggested on Wednesday. It also significantly pushes back the date for when these four-limbed pioneers made this important evolutionary step that would eventually lead to humans conquering the globe. The tracks were found by amateur archaeologists on a 30-centimetre-wide sandstone slab in a mountainous area of the southeastern Australian state of Victoria. First there was a single footprint of an unknown animal which has "raindrop pockmarks all over it," Per Ahlberg, a palaeontologist at Sweden's Uppsala University, told AFP. This suggests it was made before the brief shower, said the senior author of a new Nature study describing the discovery. Then there were two sets of tracks from after the rain. The second set of tracks suggest this reptile ancestor "was in more of a hurry", he added. "You see the claws making long scratches on the ground." - 'Keyholes' into 'lost world' - The researchers cannot determine whether both sets of tracks were made by the same individual animal, but Ahlberg thinks this is unlikely. The animal was 60-80 centimetres long and would have looked "quite lizard-like", he added. That the animal had claws is a clear sign it was an amniote, a group of animals which today includes mammals, birds and reptiles. Its ancestor tetrapods -- notable for their four limbs -- split into two groups, amniotes and amphibians. While amphibians had to return to water to lay their eggs, amniotes evolved to have eggs strong enough to survive on land, shedding its last connection to water life. The discovery indicates that amniotes existed 35 to 40 million years earlier than previously thought, during the turn of the Devonian and Carboniferous periods, the study said. This suggests the "water-to-land-dwelling transition" may have taken place in just 50 million years, much quicker than had been believed, Stuart Sumida of California State University commented in Nature. That would be just the latest twist in the tale of how animals rose from the ocean to dominate the land. "The only way to ever understand it is to look through these tiny little keyholes that we find into this strange, dark, lost world," Ahlberg said. pcl-dl/jj
Business Mayor
15-05-2025
- Science
- Business Mayor
Bombshell discovery of 'earliest footprints ever' completely rewrites theory of evolution
The sandstone slab from the earliest Carboniferous of Australia (Image: Grzegorz Niedźwiedzk / SWNS) 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. A reconstruction of the reptile. (Image: Marcin Ambrozik / SWNS) 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.
CBC
15-05-2025
- Science
- CBC
Oldest fossil footprints from reptile found in Australia
Scientists in Australia have identified the oldest known fossil footprints of a reptile-like animal, dated to around 350 million years ago. The discovery suggests that after the first animals emerged from the ocean around 400 million years ago, they evolved the ability to live exclusively on land much faster than previously assumed. "We had thought the transition from fin to limb took much longer," said California State University paleontologist Stuart Sumida, who was not involved in the new research. Previously the earliest known reptile footprints, found in Canada, were dated to 318 million years ago. The ancient footprints from Australia were found on a slab of sandstone recovered near Melbourne and show reptile-like feet with long toes and hooked claws. Scientists estimate the animal was about 80 centimetres long and may have resembled a modern monitor lizard. The findings were published Wednesday in Nature. Earliest animal with claws The hooked claws are a crucial identification clue, said study co-author and paleontologist Per Ahlberg at Uppsala University in Sweden. "It's a walking animal," he said. Only animals that evolved to live solely on land ever developed claws. The earliest vertebrates — fish and amphibians — never developed hard nails and remained dependent on watery environments to lay eggs and reproduce. But the branch of the evolutionary tree that led to modern reptiles, birds and mammals — known as amniotes — developed feet with nails or claws fit for walking on hard ground. "This is the earliest evidence we've ever seen of an animal with claws," said Sumida. At the time the ancient reptile lived, the region was hot and steamy and vast forests began to cover the planet. Australia was part of the supercontinent Gondwana. The fossil footprints record a series of events in one day, Ahlberg said. One reptile scampered across the ground before a light rain fell. Some raindrop dimples partially obscured its trackways. Then two more reptiles ran by in the opposite direction before the ground hardened and was covered in sediment. Fossil "trackways are beautiful because they tell you how something lived, not just what something looked like," said co-author John Long, a paleontologist at Flinders University in Australia.
