Latest news with #Kryoryctes
Yahoo
06-05-2025
- Science
- Yahoo
Scientists Reveal a Surprising New Theory on Where Echidnas Came From
New analysis of a 100-million-year-old fossil embedded in a rocky cove in Australia suggests echidnas may have evolved from swimming ancestors. That's basically unheard of: While there are many examples of land-dwelling mammals evolving into a more aquatic lifestyle, it seems that at some point, echidnas went in the opposite direction. Since its discovery in the early '90s, paleontologists have been debating what kind of animal left behind the fossilized arm bone. They know it was a member of the monotreme order, mammals that lay eggs instead of giving birth to live young. Based on the bone's outward appearance, some think it belonged to a land-bound ancestor of modern echidnas. Others say it might have been a swimming monotreme that pre-dates both of its living kin, echidnas and platypus. New analysis on the tiny humerus bone, which belonged to the prehistoric species Kryoryctes cadburyi, supports an aquatic origin story. "While the external structure of a bone allows you to directly compare it with similar animals to help work out the animal's relationships, the internal structure tends to reveal clues about its lifestyle and ecology," says paleontologist Suzanne Hand from the University of New South Wales, who led the study. "The internal structure doesn't necessarily give you information about what that animal actually is, but it can tell you about its environment and how it lived." Peeking inside the fossil with microCT scans, Hand and her team discovered the bone has a thick, heavy wall and a tiny medullary cavity (the hollow space inside bones where red and white blood cells are formed). Bones like this are seen in semi or fully aquatic mammals, like sea otters, dugongs, and platypus. Like the weight belt scuba divers use to stay underwater, these traits reduce the animal's buoyancy so it can remain underwater with little effort. "The microstructure of the fossil Kryoryctes humerus is more like the internal bone structure seen in platypuses, in which their heavy bones act like ballast allowing them to easily dive to forage for food," says Hand. On land, such dense and heavy bones are a disadvantage, not only because it takes more effort to lug them around, but also because they are more prone to fractures. This is why such traits are not seen in echidnas, which have very thin bone walls. The team also conducted phylogenetic analysis, piecing together where K. cadburyi sits in the mammalian and monotreme family trees. This revealed the species is indeed a stem monotreme, sharing a common ancestor with platypus and echidnas. It's very strange news in terms of echidna evolution. It suggests their ancestor was a swimming, burrowing monotreme that eventually hung up the towel for a very different life on land. There are a few other clues that this might be the case. "The bill of the platypus is well known to have lots of highly sensitive receptors that detect tiny electrical currents generated by prey," Hand points out. "And while the beak of the echidnas has fewer receptors, people have suggested that these receptors are a leftover of their platypus heritage, as are remnants of the platypus bill that can be found in the beak of echidna embryos." Echidnas also have hind feet turned backwards, which helps them with digging, in the same way platypus use their backwards feet like rudders to propel them through water. Perhaps this is why echidnas have been known to island hop. This foot orientation isn't seen in any other mammals. Perhaps echidnas weren't left on shore by the intrepid, water-faring platypus. Maybe echidnas were the ones that decided to venture out into the unknown. "We're talking about a semiaquatic mammal that gave up the water for a terrestrial existence, and while that would be an extremely rare event, we think that's what happened with echidnas," says Hand. This research was published in PNAS. This Adorable Sea Lion Can Keep a Beat Better Than Some Humans Mysterious Critters Set to Return After 17 Years Underground Plants Really Do 'Scream'. We Just Never Heard Them Until Now.
Yahoo
03-05-2025
- Science
- Yahoo
Echidna ancestors lived watery lifestyles like platypuses 100 million years ago
As the world's only surviving egg-laying mammals, Australasia's platypus and four echidna species are among the most extraordinary animals on Earth. They are also very different from each other. The platypus is well adapted for a semi-aquatic lifestyle, spending up to 20 hours a day swimming in Australian waterways to forage for freshwater invertebrates. Echidnas, on the other hand, live entirely on land. They are widely distributed across Australia and New Guinea, and adapted for feeding on termites, ants and earthworms. How did these differences emerge? Some researchers think echidnas evolved from a swimming, platypus-like ancestor. This hypothesis is based on evidence from aspects of their genes and anatomy, and from hypotheses about their evolutionary history. However, this idea is controversial because fossil evidence for such a profound evolutionary transformation has been lacking – until now. In our study published today in PNAS, we gleaned new data from a 108-million-year-old mammal humerus (arm bone), found 30 years ago at Dinosaur Cove, Victoria, by a team from Museums Victoria. This arm bone, from a species called Kryoryctes cadburyi, belongs to an ancestral monotreme – a semi-aquatic burrower like the platypus. Our findings support the hypothesis that land-living echidnas evolved from a swimming ancestor. Kryoryctes lived during the Age of Dinosaurs (the Mesozoic), when monotremes and monotreme relatives were more common than they are today. Glimpses of this past diversity are found in the fossil record in southern Victoria and Lightning Ridge, New South Wales. Nevertheless, Australian Mesozoic mammal fossils are exceedingly rare, and mostly consist of teeth and jaws. Kryoryctes is the only one known from a limb bone, which provides significant information about its identity, relationships and lifestyle. In order to test the evolutionary relationships of Kryoryctes, we added it to a broader data set of 70 fossil and modern mammals. From there, we calculated an evolutionary tree. This showed Kryoryctes is an ancestral monotreme. We also compared the external shape of the Kryroryctes humerus bone to living monotremes. These analyses indicated the bone is more like those of echidnas, rather than platypuses. But it was a different story on the inside. When we looked at the internal structure of the Kryoryctes humerus with several 3D scanning techniques, we uncovered microscopic features of this arm bone that were actually more like those of the platypus. Such tiny features inside bones yield crucial clues about the lifestyle of an animal. Numerous previous studies link bone microstructure in mammals and other tetrapods (four-limbed animals) with their ecology. Using the wealth of data available for living mammals, we compared characteristics of the Kryoryctes humerus microstructure to those in platypuses, echidnas and 74 other mammal species. These analyses confirmed that the Kryoryctes humerus has internal bone features found in semi-aquatic burrowing mammals (such as the platypus, muskrat and Eurasian otter), rather than land-living burrowing mammals such as the echidna. This discovery suggests that a semi-aquatic lifestyle is ancestral for all living monotremes. It also suggests the amphibious lifestyle of the modern platypus had its origins at least 100 million years ago, during the Age of Dinosaurs. In this scenario, the modern platypus lineage has retained the ancestral semi-aquatic burrowing lifestyle for more than 100 million years. Echidnas would have reverted to a land-based way of life more recently. For echidnas, a return to land appears to have resulted in adaptations such as their long bones becoming lighter, as shown in our study. They possibly also lost several other features more useful for spending time in the water rather than on land, including the loss of a long tail, reduction of webbing between fingers and toes, reduction of the duck-like bill to a narrow beak, and a reduced number of electroreceptors on that beak. However, precisely when this evolutionary transformation occurred is not yet known. The answer must wait until early echidna fossils are found – so far, nothing definitive has turned up anywhere. The modern habitats of monotremes are increasingly under threat from environmental degradation, interactions with humans and feral predators, and climate change. This is especially true for platypuses. To ensure the survival of this ancient lineage, we need to better understand how their unique features evolved and adapted. This article is republished from The Conversation. It was written by: Sue Hand, UNSW Sydney; Camilo López-Aguirre, University of Toronto; Laura A. B. Wilson, Australian National University, and Robin Beck, University of Salford Read more: 1 billion years ago, a meteorite struck Scotland and influenced life on Earth Here's how to make your backyard safer and cooler next summer How human connections shaped the spread of farming among ancient communities Sue Hand receives funding from the Australian Research Council Laura A. B. Wilson receives funding from the Australian Research Council Robin Beck receives funding from the UK's National Environmental Research Council, and the Australian Research Council. Camilo López-Aguirre does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.
Observer
30-04-2025
- Science
- Observer
Study sheds light on origin of Australia's odd echidna
Australia's burrowing echidna evolved from a water-dwelling ancestor in an "extremely rare" biological event, scientists said Tuesday in a new study of the peculiar egg-laying mammals. With powerful digging claws, protective spikes and highly sensitive beaks, echidnas are well suited to a life shuffling through the forest undergrowth. But a team of Australian and international scientists believe many of the echidna's unusual traits were first developed millions of years ago when its ancestors splashed through the water. "We're talking about a semiaquatic mammal that gave up the water for a terrestrial existence," said paleontologist Suzanne Hand, from the University of New South Wales. "While that would be an extremely rare event, we think that's what happened with echidnas." Echidnas and another Australian oddity, the semi-aquatic platypus, are believed to have evolved from a common ancestor called Kryoryctes cadburyi that lived in Australia more than 100 million years ago. Researchers studied the single known bone fragment left by this ancestor, which was discovered among a trove of fossils at Dinosaur Cove in southern Australia some 30 years ago. Platypus bones were similar to this ancient ancestor, Hand said, with a thick and heavy structure that provided ballast for diving. Echidnas, in comparison, had very thin bone walls that made it easier to walk on land, Hand said. This indicated echidnas were descended from a water-dwelling ancestor but had evolved to live on land, the research found. It was far more common for prehistoric mammals to go from land to water, Hand said, pointing towards seals, whales, dolphins and dugongs. The researchers said these findings appeared to be supported by other echidna traits. Echidnas have backward-facing hind feet that help them shift mounds of soil when burrowing. These feet may have first developed as rudders helping the echidna's ancestor navigate fast-moving waterways, Hand said. Echidnas also have a "diving reflex" when submerged in water, which tells their body to conserve oxygen helping them hold their breath for longer. Echidnas and platypus are monotremes, a rare group of mammals that lay eggs instead of live young. "We're hoping we'll discover other ancestral monotremes that will help unravel the early history of this most fascinating group of mammals," said study co-author Michael Archer. The research was published in peer-reviewed journal PNAS. —AFP
Yahoo
30-04-2025
- Science
- Yahoo
The surprising evolution of the weirdest animals on Earth, according to a new study
Sign up for CNN's Wonder Theory science newsletter. Explore the universe with news on fascinating discoveries, scientific advancements and more. The story of two of the strangest animals on the planet just got a little stranger, thanks to clues revealed by a lone fossil specimen that scientists now say represents a long-extinct ancestor. The new research could upend what's known of the evolution of the most primitive mammals alive today. Found in Australia and New Guinea, the platypus and echidna are called monotremes, and they are unique for being the only mammals that lay eggs. The amphibious platypus has a bill and webbed feet, like a duck, and a beaver-esque tail. The small creature spends much of its time hunting for food in the water. The echidna — fittingly known as the spiny anteater — lives entirely on land, is covered in pointy quills and has rear feet that face backward, kicking up dirt as the animal burrows into the ground. Neither animal has teeth, and though they both produce milk, they secrete it through their skin for babies (often called puggles) to lap at, because they lack nipples. 'There's plenty of weirdness to go around on these little things,' said Dr. Guillermo W. Rougier, a professor in the department of anatomical sciences and neurobiology at Kentucky's University of Louisville who studies early mammalian evolution. 'They are one of the defining groups of mammals,' Rougier said. 'The typical mammal from the time of dinosaurs probably shared a lot more biology with a monotreme than with a horse, a dog, a cat or ourselves.' Therefore, he said, monotremes provide a window into the origins of mammals on Earth. A new study published Monday in the journal Proceedings of the National Academy of Sciences opens that window a little further. Research led by paleontologist Suzanne Hand, a professor emeritus at the University of New South Wales' School of Biological, Earth and Environmental Sciences in Australia, reveals the internal structure of the only known fossil specimen of the monotreme ancestor Kryoryctes cadburyi, which lived more than 100 million years ago. The fossil, a humerus, or upper arm bone, was discovered in 1993 at Dinosaur Cove in southeastern Australia. From the outside, the specimen looked more like a bone from a land-dwelling echidna than a water-loving platypus. But when the researchers peered inside, they saw something different. 'By using advanced 3D imaging approaches, we have been able to illuminate previously unseen features of this ancient bone, and those have revealed a quite unexpected story,' said study coauthor Dr. Laura Wilson, a senior lecturer at the university's School of Biological, Earth and Environmental Sciences. The team found that internally, the fossil had characteristics of the semiaquatic platypus: a thicker bone wall and smaller central cavity. Together, these traits make bones heavier, which is useful in aquatic animals because they reduce buoyancy, so it's easier for the creatures to dive underwater to forage for food. By contrast, echidnas, which live solely on land, have much thinner, lighter bones. The finding supports the popular, but unproven, hypothesis that Kryoryctes is a common ancestor of both the platypus and echidna, and that at the time of the dinosaurs, it may have lived at least partially in the water. 'Our study indicates that the amphibious lifestyle of the modern platypus had its origins at least 100 million years ago,' Hand said, 'and that echidnas made a much later reversion to a fully terrestrial lifestyle.' There are well-known examples of animals evolving from land to water — for example, it is believed that dolphins and whales evolved from land animals and share lineage with hippos. But there are few examples that show evolution from water to land. The transition requires 'substantial changes to the musculoskeletal system,' Wilson said, including new positioning of the limbs for life on land and lighter bones to make moving less energy-intensive. A land-to-water transition could explain the echidna's bizarre backward feet, which Hand said it may have inherited from a swimming ancestor that used its hind legs as rudders. 'I think that they very elegantly prove the suggestion that these animals were adapted to a semiaquatic life very early on,' said Rougier, who was not involved in the study, though he did have contact with the authors during their research. The primitive history of these unusual animals, he said, is 'truly crucial' to our understanding of how mammals (including humans) came to be. 'Monotremes are these living relics from a very long distant past. You and a platypus probably had the last common ancestor over 180 million years ago,' he said. 'There is no way to predict the biology of this last common ancestor without animals like monotremes.' Amanda Schupak is a science and health journalist in New York City.
CNN
30-04-2025
- Science
- CNN
The surprising evolution of the weirdest animals on Earth, according to a new study
The story of two of the strangest animals on the planet just got a little stranger, thanks to clues revealed by a lone fossil specimen that scientists now say represents a long-extinct ancestor. The new research could upend what's known of the evolution of the most primitive mammals alive today. Found in Australia and New Guinea, the platypus and echidna are called monotremes, and they are unique for being the only mammals that lay eggs. The amphibious platypus has a bill and webbed feet, like a duck, and a beaver-esque tail. The small creature spends much of its time hunting for food in the water. The echidna — fittingly known as the spiny anteater — lives entirely on land, is covered in pointy quills and has rear feet that face backward, kicking up dirt as the animal burrows into the ground. Neither animal has teeth, and though they both produce milk, they secrete it through their skin for babies (often called puggles) to lap at, because they lack nipples. 'There's plenty of weirdness to go around on these little things,' said Dr. Guillermo W. Rougier, a professor in the department of anatomical sciences and neurobiology at Kentucky's University of Louisville who studies early mammalian evolution. 'They are one of the defining groups of mammals,' Rougier said. 'The typical mammal from the time of dinosaurs probably shared a lot more biology with a monotreme than with a horse, a dog, a cat or ourselves.' Therefore, he said, monotremes provide a window into the origins of mammals on Earth. A new study published Monday in the journal Proceedings of the National Academy of Sciences opens that window a little further. Research led by paleontologist Suzanne Hand, a professor emeritus at the University of New South Wales' School of Biological, Earth and Environmental Sciences in Australia, reveals the internal structure of the only known fossil specimen of the monotreme ancestor Kryoryctes cadburyi, which lived more than 100 million years ago. The fossil, a humerus, or upper arm bone, was discovered in 1993 at Dinosaur Cove in southeastern Australia. From the outside, the specimen looked more like a bone from a land-dwelling echidna than a water-loving platypus. But when the researchers peered inside, they saw something different. 'By using advanced 3D imaging approaches, we have been able to illuminate previously unseen features of this ancient bone, and those have revealed a quite unexpected story,' said study coauthor Dr. Laura Wilson, a senior lecturer at the university's School of Biological, Earth and Environmental Sciences. The team found that internally, the fossil had characteristics of the semiaquatic platypus: a thicker bone wall and smaller central cavity. Together, these traits make bones heavier, which is useful in aquatic animals because they reduce buoyancy, so it's easier for the creatures to dive underwater to forage for food. By contrast, echidnas, which live solely on land, have much thinner, lighter bones. The finding supports the popular, but unproven, hypothesis that Kryoryctes is a common ancestor of both the platypus and echidna, and that at the time of the dinosaurs, it may have lived at least partially in the water. 'Our study indicates that the amphibious lifestyle of the modern platypus had its origins at least 100 million years ago,' Hand said, 'and that echidnas made a much later reversion to a fully terrestrial lifestyle.' There are well-known examples of animals evolving from land to water — for example, it is believed that dolphins and whales evolved from land animals and share lineage with hippos. But there are few examples that show evolution from water to land. The transition requires 'substantial changes to the musculoskeletal system,' Wilson said, including new positioning of the limbs for life on land and lighter bones to make moving less energy-intensive. A land-to-water transition could explain the echidna's bizarre backward feet, which Hand said it may have inherited from a swimming ancestor that used its hind legs as rudders. Related video Platypus released in Australian national park for the first time in 50 years 'I think that they very elegantly prove the suggestion that these animals were adapted to a semiaquatic life very early on,' said Rougier, who was not involved in the study, though he did have contact with the authors during their research. The primitive history of these unusual animals, he said, is 'truly crucial' to our understanding of how mammals (including humans) came to be. 'Monotremes are these living relics from a very long distant past. You and a platypus probably had the last common ancestor over 180 million years ago,' he said. 'There is no way to predict the biology of this last common ancestor without animals like monotremes.'
