Latest news with #amniotes
CNN
22-05-2025
- Science
- CNN
Tiny clawed tracks left in ancient mud are the oldest reptile footprints
Distinct clawed footprints found on a slab of 356 million-year-old rock from Australia suggest that reptile relatives appeared between 35 million and 40 million years earlier than previously believed. The tracks also push back the origin of amniotes, a group that includes reptiles, birds and mammals, and provide new evidence about how animals transitioned from existing solely in the seas to living on land. Amniotes represent a crucial part of the transition from aquatic to terrestrial life because they were the only tetrapods, or four-limbed creatures, that evolved to reproduce on land. Previously, the oldest body fossils and footprints associated with amniotes were dated to 318 million years ago in Canada. But the new findings, published on May 14 in the journal Nature, challenge such long-held assumptions and signal that the transformation of tetrapods living in water to living on land likely occurred much more rapidly than scientists thought. 'I'm stunned,' said study coauthor Per Erik Ahlberg, professor of evolution and developmental biology at Uppsala University in Sweden, in a statement. 'A single track-bearing slab, which one person can lift, calls into question everything we thought we knew about when modern tetrapods evolved.' The location of the discovery indicates that Australia, once a central part of the ancient southern supercontinent of Gondwana that also included present-day Africa, South America, Arabia, Madagascar, Antarctica and India, may be the ideal place to look for more amniote and reptile fossils — and where they originated, according to the study authors. The rock slab, found by amateur paleontologists and study coauthors Craig Eury and John Eason in the Snowy Plains Formation in Victoria, Australia, appears to show two sets of tracks from the same animal that represent the earliest clawed footprints ever discovered. The shape of the feet is similar to a modern water monitor's, and though the animal's exact size is unknown, it may have resembled a small goanna-like creature about 80 centimeters (31 inches) in length, said lead study author John Long, strategic professor in paleontology at Flinders University. Asian water monitors are large lizards native to South and Southeast Asia, while goannas are large lizards commonly found in Australia. Hooked claws, a key feature specific to reptiles, might have enabled the primitive tetrapod to dig and climb trees. The animal that made the footprints is the oldest known reptile and oldest known amniote, Ahlberg said. And it's helping scientists crack the code on how tetrapods evolved. 'Our new find implies that the two main evolutionary lines leading to modern tetrapods — one, the line to modern amphibians, and two, the line leading to reptiles, mammals and birds — diverged from each other much earlier in time than previously thought, likely back in the Devonian Period about 380 million years ago,' Long said. Prior to this finding, the Devonian Period was believed to be a time of primitive fishlike tetrapods and 'fishapods' like Tiktaalik, which exhibited traits of fish and early tetrapods and began to explore shorelines in limited ways. But the new study reveals a diversity of large and small tetrapods, some aquatic and others largely or entirely terrestrial, likely lived at the same time. 'One of the implications of our research is that tetrapod diversity at this time was higher, and included more advanced forms, than had been thought,' Ahlberg wrote in an email. It's crucial to understand when life shifted from being entirely aquatic to terrestrial because it is one of the biggest steps in the evolution of life, Long said. This transition showed that animals were no longer dependent on living in or near water. The transition occurred partly because amniotes evolved to reproduce with hard-shelled, rather than soft-shelled, eggs. 'The vertebrates' move onto land was an important part, and within that a key step was the evolution of the amniotic egg in the immediate common ancestors of reptiles and mammals,' Ahlberg said. 'So these events form a key episode in our own ancestry as well as the history of the planet.' The new study pushes the origin of amniotes much deeper into the Carboniferous Period, 299 million to 359 million years ago, which allows a much greater length of time for the diversification of early reptiles, said Stuart Sumida, president of the Society of Vertebrate Paleontology and professor of biology at California State University, San Bernardino. Sumida, who wrote an accompanying article to release with the study, did not participate in the new research. Long has been studying ancient fish fossils from the Mansfield district, where the slab was found, since 1980. 'The Mansfield area has produced many famous fossils, beginning with spectacular fossil fishes found 120 years ago, and ancient sharks. But the holy grail that we were always looking for was evidence of land animals, or tetrapods, like early amphibians. Many had searched for such trackways but never found them — until this slab arrived in our laboratory to be studied,' he said. Fossils from the Mansfield district have shed light on how sexual organs might have first evolved in ancient armored fish. Now, the researchers want to know what else lived in Gondwana alongside the ancient reptile they found. The findings have inspired researchers to broaden the search for fossils of the earliest amniotes, and their close relatives, to the southern continents, Sumida said. 'Most of the skeletal fossil discoveries of the earliest amniotes are known from continents derived from the northern components of Pangea,' Sumida said in an email. 'Discoveries there suggested that amniote origins might be in those regions. It seems clear to me now that we must now expand our search for Early Carboniferous localities in Australia, South America, and Africa.'
CNN
22-05-2025
- Science
- CNN
Tiny clawed tracks left in ancient mud are the oldest reptile footprints
Distinct clawed footprints found on a slab of 356 million-year-old rock from Australia suggest that reptile relatives appeared between 35 million and 40 million years earlier than previously believed. The tracks also push back the origin of amniotes, a group that includes reptiles, birds and mammals, and provide new evidence about how animals transitioned from existing solely in the seas to living on land. Amniotes represent a crucial part of the transition from aquatic to terrestrial life because they were the only tetrapods, or four-limbed creatures, that evolved to reproduce on land. Previously, the oldest body fossils and footprints associated with amniotes were dated to 318 million years ago in Canada. But the new findings, published on May 14 in the journal Nature, challenge such long-held assumptions and signal that the transformation of tetrapods living in water to living on land likely occurred much more rapidly than scientists thought. 'I'm stunned,' said study coauthor Per Erik Ahlberg, professor of evolution and developmental biology at Uppsala University in Sweden, in a statement. 'A single track-bearing slab, which one person can lift, calls into question everything we thought we knew about when modern tetrapods evolved.' The location of the discovery indicates that Australia, once a central part of the ancient southern supercontinent of Gondwana that also included present-day Africa, South America, Arabia, Madagascar, Antarctica and India, may be the ideal place to look for more amniote and reptile fossils — and where they originated, according to the study authors. The rock slab, found by amateur paleontologists and study coauthors Craig Eury and John Eason in the Snowy Plains Formation in Victoria, Australia, appears to show two sets of tracks from the same animal that represent the earliest clawed footprints ever discovered. The shape of the feet is similar to a modern water monitor's, and though the animal's exact size is unknown, it may have resembled a small goanna-like creature about 80 centimeters (31 inches) in length, said lead study author John Long, strategic professor in paleontology at Flinders University. Asian water monitors are large lizards native to South and Southeast Asia, while goannas are large lizards commonly found in Australia. Hooked claws, a key feature specific to reptiles, might have enabled the primitive tetrapod to dig and climb trees. The animal that made the footprints is the oldest known reptile and oldest known amniote, Ahlberg said. And it's helping scientists crack the code on how tetrapods evolved. 'Our new find implies that the two main evolutionary lines leading to modern tetrapods — one, the line to modern amphibians, and two, the line leading to reptiles, mammals and birds — diverged from each other much earlier in time than previously thought, likely back in the Devonian Period about 380 million years ago,' Long said. Prior to this finding, the Devonian Period was believed to be a time of primitive fishlike tetrapods and 'fishapods' like Tiktaalik, which exhibited traits of fish and early tetrapods and began to explore shorelines in limited ways. But the new study reveals a diversity of large and small tetrapods, some aquatic and others largely or entirely terrestrial, likely lived at the same time. 'One of the implications of our research is that tetrapod diversity at this time was higher, and included more advanced forms, than had been thought,' Ahlberg wrote in an email. It's crucial to understand when life shifted from being entirely aquatic to terrestrial because it is one of the biggest steps in the evolution of life, Long said. This transition showed that animals were no longer dependent on living in or near water. The transition occurred partly because amniotes evolved to reproduce with hard-shelled, rather than soft-shelled, eggs. 'The vertebrates' move onto land was an important part, and within that a key step was the evolution of the amniotic egg in the immediate common ancestors of reptiles and mammals,' Ahlberg said. 'So these events form a key episode in our own ancestry as well as the history of the planet.' The new study pushes the origin of amniotes much deeper into the Carboniferous Period, 299 million to 359 million years ago, which allows a much greater length of time for the diversification of early reptiles, said Stuart Sumida, president of the Society of Vertebrate Paleontology and professor of biology at California State University, San Bernardino. Sumida, who wrote an accompanying article to release with the study, did not participate in the new research. Long has been studying ancient fish fossils from the Mansfield district, where the slab was found, since 1980. 'The Mansfield area has produced many famous fossils, beginning with spectacular fossil fishes found 120 years ago, and ancient sharks. But the holy grail that we were always looking for was evidence of land animals, or tetrapods, like early amphibians. Many had searched for such trackways but never found them — until this slab arrived in our laboratory to be studied,' he said. Fossils from the Mansfield district have shed light on how sexual organs might have first evolved in ancient armored fish. Now, the researchers want to know what else lived in Gondwana alongside the ancient reptile they found. The findings have inspired researchers to broaden the search for fossils of the earliest amniotes, and their close relatives, to the southern continents, Sumida said. 'Most of the skeletal fossil discoveries of the earliest amniotes are known from continents derived from the northern components of Pangea,' Sumida said in an email. 'Discoveries there suggested that amniote origins might be in those regions. It seems clear to me now that we must now expand our search for Early Carboniferous localities in Australia, South America, and Africa.'
Washington Post
14-05-2025
- Science
- Washington Post
Oldest footprints of first ‘reptile' found by fossil hunters
More than 300 million years ago, long before the age of dinosaurs, there lived a four-legged, clawed creature that had evolved to survive and reproduce entirely on land, away from the shark-swarmed seas where its ancestors first appeared. It could lay eggs on land, unlike amphibians. The creature was part of a large group known as 'amniotes.'
The Guardian
14-05-2025
- Science
- The Guardian
‘Turning point': claw print fossils found in Australia rewrite story of amniotes by 40 million years
Fossilised claw prints found in Australia suggest amniotes – the ancestors of reptiles, birds and mammals – evolved about 40m years earlier than thought. The footprints, in sandstone dated 354m to 358m years old, were probably made by reptiles crossing a surface dimpled by raindrops. Researchers said the trackways represent the oldest evidence of amniotes on the planet. 'The implications are profound,' said Flinders University palaeontologist Prof John Long, lead author of the paper, published in Nature. 'It's rewriting the story of the amniotes – evolving much earlier than people had thought.' Sign up for Guardian Australia's breaking news email The discovery also hinted at their emergence in the ancient southern continent of Gondwana, rather than in the northern hemisphere, he said. The trackways were much older than previous amniote fossils and tracks – from Europe and North America – dated to about 318 million years ago, as well as an earlier example identified by the authors in the course of their research. Fossil hunters Craig Eury and John Eason found the footprints on the banks of the Broken River near the town of Mansfield, on Taungurung country, 200km north-east of Melbourne. Long, whose connection to fossils of the area stretches back 45 years, has kept in contact with a 'local band of dedicated Mansfield locals'. He said he was 'gobsmacked' when Eason sent him an email with a photograph of the find, asking: 'Is this anything?' When the photo opened on his screen, he said: 'It was a beautiful set of not one but a couple of different sets of trackways criss-crossing the slab.' An ancient rain shower had pockmarked the slab's surface, indicating exposed ground. Later, reptilian track makers came through, leaving five-toed prints, some with imprints of claws, and scratch marks from digging. Detailed investigations by Flinders University specialists in CT scanning and trackways, and world experts in early tetrapod (four-limbed vertebrate) tracks at Uppsala University in Sweden, confirmed the significance of the find. The discovery pushed back the arrival of amniotes to the early carboniferous, a period named for the rich coal beds that formed in the northern hemisphere at the time, Long said. The period was a 'turning point' in the Earth's history, he said. Oxygen levels were high and huge forests dominated the land. Swamps were full of amphibians, some up to five metres in length, and huge sharks invaded the rivers. A great diversity of animals and plants started appearing – bony fishes and seed-bearing trees. 'It was really a changing of the guard from the archaic fishes and plants that characterised the first half of the palaeozoic era, to the kind of assemblages that would dominate right through to today.' That included the amniotes – defined by the amniotic membrane that allowed them to lay eggs or reproduce outside of water – adapted for life on the land. 'It's a very exciting story for Australian science,' Long said. 'It hints there's a lot more work to do [and] a lot more field work. Now we've got the footprints we need to find the bones of these things.' Dr Erich Fitzgerald, a senior curator of vertebrate palaeontology at Museums Victoria Research Institute, who was not involved in the study, said it was a 'provocative discovery with potentially far-reaching implications'. 'What we need next is to find body fossils – bones from these rocks – that can confirm the presence of amniotes so long ago.' Fitzgerald said the discovery of the trackway highlighted the importance of 'Australia's spectacular fossil record', much of which was relatively understudied, and revealed the importance of collaboration between professional scientists and keen members of the public. 'This is a jaw-droppingly beautiful example of the importance of continuing to search for and collect new fossils,' he said. 'Palaeontology is still in the process of unravelling the mysteries of the evolution of life … and the evolution of us.'
