On July 14, 2026, "Gus," one of the most complete specimens of Tyrannosaurus rex, went to an as yet unidentified buyer for US$50.1 million. This auction at Sotheby's set a record for most valuable fossil ever sold. Another dinosaur has entered the luxury collectibles market, a reminder that even Earth's deepest history can be sold to the highest bidder.

To paleontologists like me, however, a fossil like "Gus" — excavated from the Hell Creek Formation in South Dakota over three years starting in 2021 by commercial collector Thomas Heitkamp and his team — is not a trophy or a work of art. It is an irreplaceable scientific archive. Fossils preserve evidence of evolution, extinction, growth, disease, injury and ancient ecosystems. They are finite, nonsubstitutable records of life’s history on Earth.

Science depends on independent verification of claims and healthy debate. Researchers must be able to revisit specimens, test earlier conclusions and ask new questions.

But once a scientifically important fossil enters a private collection, access for researchers is no longer guaranteed. Collectors typically sequester their fossils in their homes. Even when privately owned specimens are loaned to museums, the owners can change their minds, ending access at any time. This issue is especially of note when it comes to Tyrannosaurus rex; a 2025 study found that while there were 61 T. rex fossils in public trusts at that time, 71 were privately held.

That is why the Society of Vertebrate Paleontology, of which I'm a long-term member and president-elect, has long argued that scientifically significant vertebrate fossils belong in the public trust, curated in museums and universities that preserve them permanently, make them available for research and share them with the public.

Finding a fossil

Supporters of commercial fossil sales often argue that without sales to private collectors, specimens like "Gus" would remain buried or erode away. They’re right about one thing: Discovery matters. Many extraordinary fossils have been found by ranchers, hikers, amateur collectors and commercial excavators. Paleontology is accessible to everyone who has an eye for observing nature — you don't need to be an expert with academic credentials to make an important discovery.

But discovery is only the beginning. A fossil's scientific value depends on careful documentation of where it was found, the rocks surrounding it, and the plants and animals preserved alongside it. Those details allow scientists to reconstruct ancient ecosystems, understand how an animal lived and died, and interpret how its remains became fossilized. When that contextual information is incomplete or lost, much of the fossil's scientific value is lost as well.

Yet even discovery, excavation and publication barely scratch the surface of a fossil's scientific importance. The greatest scientific value of a specimen often comes decades later, when researchers ask new questions and apply new technologies that earlier generations never imagined. A specimen that seems fully studied today may yield surprising new information tomorrow, but only if it is still available for study.

Delayed discoveries

Consider the iconic dinosaurs, including T. rex, Triceratops, Diplodocus and Stegosaurus, first collected more than a century ago. Early paleontologists could describe their shapes but had no way to dig deeper by peering inside the bones. Because those specimens were preserved in museum collections, later generations could revisit them with technologies that didn't exist when they were discovered.

Paleontologist Larry Witmer and his collaborators at Ohio University started using CT imaging 20 years ago to reconstruct the internal anatomy of historic dinosaur fossils without damaging them, based on how X-rays travel through specimens. Brain cavities, inner ears, air spaces, nerves and blood vessels became visible for the first time, revealing how dinosaurs balanced, heard, smelled and perceived their world.

Henry Fricke, Thomas Cullen and other geochemists have used isotopic signatures preserved in fossil teeth and eggshells to reconstruct dinosaur diets, migration patterns and body temperatures. This research has revealed how dinosaurs lived: what they ate, how they moved through ancient landscapes, and even how warm their bodies were.

More recently, molecular paleontologist Jasmina Wiemann and her collaborators have identified chemical traces preserved in fossil bone, eggshell and skin that reveal aspects of dinosaur biology unimaginable even a generation ago. Until now, paleontologists had no way to know details about metabolic rates and reproduction or the colors of skin, feathers and eggs.

In my own research I use microscopes to uncover the hidden stories preserved inside dinosaur bones and teeth. Thin sections of fossil bones reveal that dinosaurs grew more like mammals and birds than like oversized reptiles. Microscopic modifications to bones capture traces of ancient scavenging, and tiny signatures deep inside baby dinosaur bones indicate the moment of hatching.

None of these discoveries would have been possible if the original fossils had vanished into inaccessible private collections.

Shared natural heritage, on the auction block

Fossils are not static objects whose scientific value is exhausted once they are described. Their value grows as science advances, but only if future researchers can continue to examine the original specimens.

Of course, sometimes dinosaur fossils are rescued from obscurity through purchase and immediate deposition or donation to natural history museums. Some of the world's most important dinosaur fossils are accessible today because individuals, companies or organizations with the means to acquire extraordinary specimens recognized that they belong where scientists can continue to study them and where future generations can learn from them.

Purchasing a fossil in order to place it permanently in the public trust is fundamentally different from acquiring it as a private collectible: One expands access, the other leaves access uncertain.

But as fossil prices rise into the millions, museums increasingly cannot compete. The most significant fossils are no longer reliably entering public collections. Instead, they are becoming luxury assets whose market value supersedes their scientific value.

Dinosaurs belong to our shared natural heritage. They inspire wonder because they connect all of us to a world unimaginably older than our own. For me, the question raised by auctions like the one on July 14 of "Gus" is not who can afford to own these relics of the past. It is whether future generations have the chance to study and learn from them.

This edited article is republished from The Conversation under a Creative Commons license. Read the original article.

How much do you know about the king of the dinosaurs? Test your knowledge with our T. rex quiz!

The first dinosaur found in Antarctica belonged to a group that included the largest animals ever to walk the planet, a new study finds.

A backbone from the 82 million-year-old giant was discovered more than 40 years ago, but at the time, researchers assumed it came from an ancient marine reptile. Now a new study, published June 29 in the journal Acta Palaeontologica Polonica, has revealed that it was actually a titanosaur — the group of long-necked sauropods that included the largest land animals on record.

"At first glance this appears to be an unremarkable fossil, but it holds an important place in the history of Antarctic exploration as the first dinosaur fossil found on the continent," study first author Paul Barrett, a paleontologist at the Natural History Museum in London, said in a statement.

While this fossil now holds the record for the first dinosaur fossil found in Antarctica, other dinosaur fossils were identified on the continent after its discovery, so it's not the only known Antarctic dinosaur. In fact, researchers have identified a variety of dinosaurs on Antarctica, with another sauropod fossil identified as a titanosaur in 2011.

The newly identified dinosaur was around 20 to 23 feet (6 to 7 meters) long. That's very small compared with the largest-known titanosaurs, which could grow up to 123 feet (37.5 m) long. However, as the fossil is just a fragment of a vertebra, researchers are unable to narrow down which species the Antarctic titanosaur belonged to, and it's possible that the individual was only a juvenile when it died.

Mike Thomson, a British Antarctic Survey geologist, found the fossil during an expedition to James Ross Island in 1985. The island, which has been the site of multiple dinosaur discoveries, is located off the northeastern Antarctic Peninsula, south of the 600-mile-wide (965 kilometers) Drake Passage that separates South America from Antarctica.

Antarctica is well known for its icy landscapes, but when titanosaurs roamed Earth, the continent was still attached to South America and full of temperate forests. Antarctica's dinosaurs were so far south that they would have lived in constant twilight during the winter months, according to a news article published by the Natural History Museum.

The authors of the new study identified the dinosaur using high-resolution CT scans, which enabled them to look inside the fossil. Dating back to the Cretaceous period (143 million to 66 million years ago), the titanosaur lived in the last age of the non-avian dinosaurs, before an enormous asteroid hit what is now Mexico's Yucatan Peninsula 66 million years ago and wiped them out.

The Antarctic titanosaur helps researchers better understand how dinosaurs spread across Earth's southern continents, which at the time were combined into a supercontinent called Gondwana. The presence of titanosaurs on Antarctica suggests that they may have used Antarctica to travel from what is now South America to New Zealand.

Other dinosaurs identified on Antarctica include small herbivores, armored ankylosaurs and bipedal predators like Imperobator, which would have shared the forests with the newly identified titanosaur. While researchers are beginning to piece together Antarctica's ancient ecosystems, they still have a lot to learn about the dinosaurs that lived there.

"There are likely many more dinosaurs to be discovered on the continent," Barrett said. "As climate change causes ice to retreat we may indeed find further evidence of this past biodiversity."

Never-before-seen fossils of newly hatched crocodile-like creatures are shining new light on how our aquatic ancestors conquered land.

Early four-limbed vertebrates (tetrapods), which would eventually give rise to humans, took their first steps on land in the Devonian period, some 419 million to 359 million years ago, marking one of the most important periods in the evolutionary history of animals.

Now, a new study published Thursday (June 18) in the journal Science has revealed that these early tetrapods were less like amphibians and more like us. Rather than having a tadpole phase in their development, as many amphibians do today, new evidence suggests that they were direct developers — growing from smaller to bigger versions of themselves, like their ancestors, humans and many other animals.

The study is an important contribution to our understanding of early tetrapods' reproductive developmental biology, said Tim Smithson, a visiting academic at the University of Cambridge who specializes in early tetrapods but was not involved in the study.

It suggests that the "earliest tetrapods that took those first steps on to land were able to rely on the successful reproductive and developmental strategies of their forebears," Smithson told Live Science in an email. "Direct development made life easier — one less thing to worry about!"

The new research was based partly on fossils from early land-dwelling predators called embolomeres. These animals looked like a cross between a crocodile and an eel and ruled river, lake and swamp habitats 350 million to 280 million years ago, during the Carboniferous and Permian periods. While these creatures could grow to more than 10 feet (3 meters) long as adults, the study unveils rare fossils from Mazon Creek, near Chicago, that preserved embolomeres as hatchlings that were days to a couple of weeks old.

"These are intimate details of the first moments of these animals' lives, and we've never seen that before for this entire part of the evolutionary tree," study co-author Jason Pardo, a postdoctoral fellow of evolutionary biology at Vilnius University in Lithuania and a research associate at the Field Museum in Chicago, told Live Science.

These fossils didn't show evidence of external gills and other tadpole-like features that the researchers would have expected from an early land dweller. The researchers then checked other fossils from before and during the "fin-to-limb transition" but found no evidence of an amphibian-like life cycle in those, either.

"For as long as we've understood evolution, we've assumed this story of how we made that transition from water to land," Pardo said. "We in fact have a completely different story."

Science upended?

A statement released by the Field Museum claimed that the study upends scientists' understanding of how animals conquered the land. However, the experts Live Science spoke to disagreed with this assertion.

"The Mazon Creek material is wonderful, the study is interesting and the interpretation of the fossils is sound, but I don't think the results are terribly surprising," Per Ahlberg, a professor of evolutionary organismal biology at Uppsala University in Sweden, told Live Science in an email.

Ahlberg, who was not involved in the new study, specializes in the early evolution of tetrapods. He noted that scientists knew some early tetrapods had a larval stage similar to that of modern salamanders ‪—‬ namely, those belonging to the group Temnospondyli, which he described as the ancestral stock of modern amphibians. However, he contends that this didn't mean scientists assumed every early tetrapod was the same.

"Nobody has been arguing in recent years that ALL early tetrapods had such a larval stage or that this was essential for enabling the transition to land," Ahlberg said. "I mean, I have been working right at the core of this research field for 40 years and I have never given it any thought."

In response, Pardo agreed that specialists in the field recognized that the data didn't support that early tetrapods had an amphibian-like development. However, he argued that even among specialists, assumptions were still made about metamorphosis — a major developmental transition, like a tadpole transforming into a frog — and amphibian-like bodies.

"Onto something big"

Study co-author Arjan Mann, an assistant curator of early tetrapods at the Field Museum, first saw the study's first baby embolomere fossil during a 2016 trip to the Field Museum while working on his doctorate. At the time, the fossil was a mystery.

Mann and Pardo mused over the fossil's identity for years before high-resolution scans with scanning electron microscopy at the Canadian Museum of Nature confirmed that the ancient creature was an embolomere, according to the museum's statement.

"I think Jason and I both knew we were onto something big, since fossils of this kind of animal and from this phase, and developmental state in early tetrapod evolution have never been found or studied before," Mann told Live Science in an email.

Along with the embolomeres, the researchers looked at megalichthyid fish from before the land transition and limbless, snake-like creatures known as aistopods from during the land transition. All showed signs of direct development, they said.

"I think the take home message of this study is that we should always challenge conventional wisdom in science, especially when these older ideas do not have substantial backing," Mann said.

The world's largest known scorpion lived at a time when other land animals were relatively small, around 415 million years ago in what is now the U.K., a new study finds.

The prehistoric creature, named Praearcturus gigas, is estimated to have grown to lengths of around 3.3 feet (1 meter) and was equipped with formidable pincers measuring roughly 6.2 inches (16 centimeters) long, according to a statement from the University of Manchester.

The scorpion would likely have been a fearsome apex predator that stalked floodplains during the Early Devonian Period, when life on land was still in its relatively early stages and dominated by small arthropods. Arthropods are now the most diverse animal group on Earth, as they include insects, crustaceans, scorpions and spiders.

The discovery that such a large scorpion was living 415 million years ago — long before the appearance of complex terrestrial ecosystems, such as forests — offers new insights into the evolutionary history of gigantism in arthropods.

"Confirming that this animal is a scorpion fundamentally changes our understanding of how and when these creatures evolved to such extraordinary sizes," study first author Richard Howard, curator of fossil arthropods at the Natural History Museum, London, said in the statement.

Remains of P. gigas, which have so far been recovered from places in England and Wales, were first documented in the 1870s, but researchers have long debated the type of animal it was.

"Praearcturus has puzzled us palaeontologists for more than a century," study co-author Russell Garwood, a paleontologist at the University of Manchester, said in the statement.

Researchers initially suspected that the remains represented a large woodlouse-like crustacean. Then in the 1980s, research suggested that the fossils instead belonged to a scorpion. But that interpretation was subsequently challenged due to the fragmentary nature of the known remains and a lack of the characteristic scorpion tail.

In the latest study, published Tuesday (June 2) in the journal Palaeontology, the authors re-examined key P. gigas specimens held in the NHM's collections using modern imaging and analytical techniques. They also compared them with other fossil material and recently described prehistoric animals that were more confidently identified as scorpions.

Their analysis indicated that P. gigas is likely a scorpion, and the team also reassigned several other specimens found in the same geological formation to the species, the study reported. Furthermore, the researchers suggested that the creature may have been at least partially aquatic based on the presence of flap-like structures known as epimera — similar to those which provide support and protection to the hard upper shells of lobsters and crabs — in some of the fossils.

"Without complex ecosystems to support Praearcturus on land, these animals probably spent part of their lives hunting in water," Howard said in a Natural History Museum statement.

A semi-aquatic lifestyle could partially explain the scorpion's greater size compared to its modern-day relatives, as water can support large bodies. But it also may reflect the relative lack of competition from other large terrestrial predators, potentially enabling it to reach sizes that would have been more difficult to attain had they been present.

"By bringing together material from several collections and using cutting edge imaging techniques, we've been able to build a clearer picture of the animal than was previously possible, which is really exciting," Garwood said.

"What makes Praearcturus so interesting is that it became enormous at a time when life on land was otherwise very small. But it was a world that could somehow support a giant predator."

A newly discovered feathered dinosaur with four wing-like limbs may have prowled the lakeside forests of what is now northwestern China, gliding between trees like a flying squirrel and snatching some of the earliest birds out of the Cretaceous sky.

The predator, named Jian changmaensis, was a close cousin of Velociraptor and belonged to a strange group of small birdlike dinosaurs called microraptors. Unlike the large and scaly "Jurassic Park" version of raptors, these animals were feathered, lightweight and glided to get around. Based on fossil evidence, J. changmaensis had long feathers on both its arms and legs, giving it the look of a tiny dragon with four wings.

The fossil, described Thursday (June 4) in the journal Annals of Carnegie Museum, is only a partial left shoulder and forelimb. But those bones were enough to reveal a new dinosaur species, and possibly solve a longstanding mystery at China’s Changma Basin, a site packed with ancient bird fossils and broken bird bones that look a lot like the pellets coughed up by modern owls.

"Our team has recovered more than one hundred bird fossils at Changma, but only this single non-avian dinosaur specimen," study co-author Matthew Lamanna, a senior dinosaur researcher and curator of vertebrate paleontology at the Carnegie Museum of Natural History in Pittsburgh, in a statement.

"[Microraptors] provide a window into what the closest ancestors of the first birds were probably like," he told Live Science via email. "Studying them yields clues as to how birds got their start and how they learned to fly."

Finding a fossil among the fragments

Paleontologists uncovered the fossil in the Lower Cretaceous Xiagou formation near Changma village in the Gansu province. The rocks there were formed during the early Cretaceous period about 124 million to 120 millions ago, when the region held a large lake teeming with birds, fish, turtles and other ancient animals.

The site is famous for fossils of Gansus yumenesis, one of the first Mesozoic birds ever found in China. Since 2002, researchers have recovered more than 100 partial bird skeletons from Changma, including fossils with preserved soft tissue such as feathers, skin and claw sheaths.

"Our subsequent expeditions throughout the rest of the 2000s and into the 2010s established Changma as one of the world's most important fossil bird localities, Lamanna said. "It was an amazing thing to be a part of."

But until now, no one had found a non-avian dinosaur fossil from the basin.

That's what made J. changmaensis stand out. Amidst the fossil fragments, the specimen consisted of a fused shoulder blade, upper arm, radius and ulna. It was preserved in three dimensions, unlike many flattened microraptor fossils from the same area.

"Jian is one of the biggest microraptor specimens that has ever been found," Jingmai O’Connor, the associate curator of fossil reptiles at the Field Museum in Chicago and co-author of the study, said in the statement. "The piece of its upper arm bone that we have is about 4 inches [10 centimeters] long, so the entire dinosaur probably had something like a four-foot [1.2 meter] wingspan, around the size of a barn owl."

Microraptors were not birds. But they were very close relatives of the dinosaur lineage that gave rise to birds. Their bodies have elements that seem to blur the line between bird and dinosaur, including claws, sickle-shaped raptor feet and feathers.

"This is neat, a new fossil of those dinosaurs that were basically on the cusp of becoming true birds," Steve Brusatte, a professor of paleontology and evolution at Scotland’s University of Edinburgh who was not involved in the study, told CNN.

The bird hunter

The Changma Basin may have been a buffet for a tree-climbing predator like J. changmaensis. The site was dominated by early birds, as is evidenced by the many pellet-like remains, possibly the dinner remains of the newfound microraptor species.

Researchers can't prove that Jian made those pellets. But it is the only non-bird body fossil found at Changma so far. Jian was also a carnivore, and was much larger than the birds preserved there.

Other microraptor fossils support the idea that these dinosaurs ate from a wide menu. Previous fossilised specimens have been found with remains of fish, lizards, mammals and birds in their guts, suggesting microraptors were opportunistic hunters rather than picky specialists.

For J. changmaensis, birds may have been especially easy targets. If the dinosaur lived partly in trees and could glide, it may have ambushed early birds from branches or moved through the canopy like a sugar glider, according to the researchers.

"We don’t have very much of Jian, just some bones from the shoulder and forelimb," Lamanna said. "It's enough to know that there was this interesting new microraptor living 120 million years ago in what's now northwestern China, but not enough to be able to learn everything we'd like to learn about these dinosaurs. Maybe one of your readers will eventually become a paleontologist and be the one who finds the rest of Jian."

There's a new T. rex in town, but this one didn't hunt on land. It ruled the ancient seas.

Scientists have described a new species of mosasaur, a member of a marine reptile group that lived at the same time as dinosaurs during the Cretaceous period (145 million to 66 million years ago). The newly named species fits into an already known genus: Tylosaurus. But its new species name, Tylosaurus rex — T. rex, for short — sets it apart from the other mosasaur species in the group.

The species name means "king of the tylosaurs," according to a new study published Thursday (May 21) in the journal Bulletin of the American Museum of Natural History. The fossils are about 80 million years old and were discovered mostly in northern Texas decades ago.

The mosasaur T. rex measured up to 43 feet (13 meters) long, or about the length of a tour bus. It had finely serrated teeth, unusually powerful jaws, and evidence on its fossils of violent combat with its own species.

"Everything is bigger in Texas and that includes the mosasaurs, apparently," study first author Amelia Zietlow, a research associate of paleontology at the American Museum of Natural History in New York City, said in a statement.

A misidentified species

While examining a fossil in the American Museum of Natural History's collection, Zietlow noticed that a specimen labeled as Tylosaurus proriger — a well-known mosasaur species first described in 1869 — didn't quite match others of its kind. The unusual fossil was discovered in 1979 near an artificial reservoir outside Dallas.

After comparing the specimen with the original name-bearing fossil of T. proriger held at Harvard's Museum of Comparative Zoology, Zietlow and her colleagues found that it belonged to a newfound species. This specimen wasn't the only misidentified specimen of this species; more than a dozen fossils at other institutions shared the same traits.

Compared with T. proriger, the newly described T. rex was 13 feet (4 m) longer, had finely serrated teeth (which T. proriger lacked) and lived several million years later. Most T. proriger fossils were discovered in what is now Kansas and are roughly 84 million years old, while the fossils now identified as T. rex are mostly from Texas and date to about 80 million years ago. At that time, the Western Interior Seaway stretched from the Gulf of Mexico up to the Arctic and was home to many sea creatures, including mosasaurs.

A violent tyrannical king

The new T. rex's anatomy suggests that, like its mosasaur relatives, it was a formidable marine predator. In addition to its massive size, T. rex had strong jaw and neck muscles.

Some fossils show signs of brutal injuries. One specimen in the collection of the Perot Museum of Nature and Science in Dallas, nicknamed "the Black Knight," is missing the tip of its snout and has a fractured lower jaw. The researchers suspect the damage was caused by another individual of the same species.

"Through our study and examination of well-preserved fossils collected throughout the north Texas region, we have evidence of violence within this species to a degree not previously seen in other Tylosaurus specimens," study co-author Ron Tykoski, vice president of science and curator of vertebrate paleontology at the Perot Museum of Nature and Science, said in the statement.

A name to remember

Other famous mosasaur specimens once identified as T. proriger will now be reassigned to to T. rex, including "Bunker," a large specimen on display at the University of Kansas that was discovered in 1911, and "Sophie," a specimen displayed at the Yale Peabody Museum.

The name also nods to an earlier idea. In the late 1960s, paleontologist John Thurmond recognized that large tylosaurs from northeast Texas might represent an unknown species. He informally called them Tylosaurus thalassotyrannus, meaning "sea tyrant."

This is not the first time "T. rex" has had a naming twist. The land-dwelling Tyrannosaurus rex almost ended up with the name Manospondylus gigas, after paleontologist Edward Cope described two partial backbones from South Dakota in 1892. Those bones were later linked to T. rex, but they were too incomplete to clearly define the species when they were first described. By the time the bones were connected to T. rex, its name was already deeply embedded in scientific literature and popular culture.

While the aquatic T. rex seems to have resolved the misidentification issue, the new study also revisited another long-standing problem in mosasaur research: The dataset used to study mosasaur evolutionary relationships has changed little in nearly 30 years. By reanalyzing the evolutionary data on the species, the team also proposed a new evolutionary family tree among tylosaurs and argued mosasaur evolution needs a broader reassessment.

"This discovery is not just about naming a new species," Zietlow said. "It highlights the need to revisit long-standing assumptions about mosasaur evolution and to modernize the tools we use to study these iconic marine reptiles."

T. rex quiz: How much do you really know about the king of the dinosaurs?

Gigantic fossils discovered in Thailand reveal the "last titan," a long-necked dinosaur that lived up to 120 million years ago when the region was semi-arid, a new study finds.

Dubbed Nagatitan chaiyaphumensis, the newfound species is the largest sauropod, or long-necked dinosaur, found in Southeast Asia to date. It likely measured about 90 feet (27 meters) in length and weighed around 30 tons (27 metric tons), according to a study published Thursday (May 14) in the journal Scientific Reports.

"Our dinosaur is big by most people's standards — it likely weighed at least 10 tonnes [11 tons] more than Dippy the Diplodocus (Diplodocus carnegii)," study first author Thitiwoot Sethapanichsakul, a paleontologist at University College London, said in a statement. However, it is not the largest known sauropod, weighing less than half as much as its South American relatives Patagotitan and Argentinosaurus.

The research team uncovered the fossils from the Khok Kruat Formation in the Chaiyaphum province of northeastern Thailand. A local resident first spotted the fossils in 2016 in a bone bed on the side of a drying pond.

Among the recovered fossils are several vertebrae, pelvic bones and leg bones, including the dinosaur's right femur, or thigh bone. Though the femur had broken into several pieces, the scientists estimated it would have been about 6.5 feet (2 meters) in length — about as high as a tall human.

N. chaiyaphumensis was a type of dinosaur known as a somphospondylan sauropod, a subgroup of large, long-necked dinosaurs that lived from the late Jurassic through the Cretaceous. Fossils from this group have been found on every continent. The shapes of N. chaiyaphumensis's vertebrae and leg bones set it apart from other previously known sauropods.

The team named the sauropod's genus Nagatitan after Naga, "the mythological serpent-like creature found in various Asian cultures, especially in northeastern Thailand, often associated with water and Buddhism," they wrote in the study. "Titan," meanwhile, is from the giants in Greek mythology. The species name chaiyaphumensis is named for the Chaiyaphum province.

During the Cretaceous (145 million to 66 million years ago), northeastern Thailand would have been a semi-arid environment, and N. chaiyaphumensis would have used its long body and large surface area to shed heat and keep cool. The fossil site was likely part of a river system during that time, so N. chaiyaphumensis would have lived alongside crocodiles, fish and fish-eating pterosaurs.

The fossils were embedded in the youngest rocks in Thailand that still contain dinosaur fossils. Though additional rock layers accumulated atop the N. chaiyaphumensis fossils, the specific conditions later in the Cretaceous period probably prevented the formation of later dinosaur fossils, the researchers said.

"Younger rocks laid down towards the end of the time of the dinosaurs are unlikely to contain dinosaur remains because the region by then had become a shallow sea," Sethapanichsakul said. "So this may be the last or most recent large sauropod we will find in Southeast Asia."

How much do you know about the king of the dinosaurs? Test your knowledge with our T. rex quiz!

In the 1970s, paleontologist John Ostrom revived the theory that modern birds are evolved from theropod dinosaurs, a group that includes Tyrannosaurus rex. But a key piece of evidence was missing: feathered fossils. Then, a chance discovery in China upended our understanding of bird evolution.

In this excerpt from "The Story of Birds: An Evolutionary History of the Dinosaurs That Live Among Us" (Mariner Books, 2026), author and paleontologist Steve Brusatte looks at the monumental shift in dinosaur research after the first feathered dinosaur was discovered.

For well over a century, since its discovery in the Bavarian lithographic mines in 1861, the fossil bird Archaeopteryx was the oldest and most primitive creature known to have feathers. Then, in the autumn of 1996, this understanding was upended. Some revolutions start with a single shot; this one began with a chance encounter and a handful of photographs.

As the trees in Central Park dropped their leaves, paleontologists from around the world converged across the street, at the American Museum of Natural History, in mid-October for the annual meeting of the Society of Vertebrate Paleontology. A few weeks earlier, the Canadian dinosaur hunter Phil Currie had been in China, leading a group of tourists to dinosaur dig sites. While there, he spied something peculiar in the backroom of a Beijing museum, discovered by a farmer named Yumin Li two months prior. It was the skeleton of a small dinosaur, about the size of a chicken, fossilized as if frozen in time, in a muddy rock imbued with volcanic ash, a sign it was overcome by a sudden cataclysm.

Rapid burial had locked in the dainty details of the skeleton, but it was the stuff surrounding the bones that caught Currie's attention. The dinosaur's body was encircled by a halo of fluff. Thin, tufty, delicate strands ran along the dinosaur's back, from the top of its head to the tip of its tail. Some of the strands looked like they branched at their base. For all the world, the fuzz looked like the downfeathers of a bird.

But this wasn't a bird; it didn’t have wings, and obviously couldn't fly. It was a bona fide dinosaur — a small coelurosaur theropod, very similar to the German Compsognathus, which Huxley had held up in the 1860s as the type of transitional reptilian species birds might have evolved from.

Currie and his Chinese colleague Pei-ji Chen snapped photographs, which they printed out at the size of index cards and brought to the conference in New York. Once there, word spread fast; the rumors of a fluffy dinosaur billowed through the hallways and meeting rooms. Somebody tracked down John Ostrom, then in the twilight of his career, three decades after his discovery of the raptor Deinonychus had reignited the theory that birds evolved from dinosaurs. Currie and Chen handed him the photos. Ostrom looked shell-shocked. He began to cry, and almost fell to the floor. "I need to sit down," he stuttered, delirium taking hold.

Here it was, finally: a dinosaur with feathers. Just as Ostrom had predicted. Just as the doubters had demanded. The final piece of the puzzle, the strongest evidence that birds have dinosaur ancestry.

A crafty journalist from The New York Times caught wind of the excitement, and the next day, the front page of the Saturday edition blared with the headline "Feathery Fossil Hints Dinosaur-Bird Link," along-side articles about Bill Clinton's reelection campaign and a Yankees World Series preview. Above the bold print was a drawing of a small meat-eating dinosaur, running on its hind legs, small arms curled up, its tail a long seesaw for balance, its neck, back, and chest covered with bushy fuzz.

The artwork was needed, because the Chinese authorities barred publication of the photos. Before the year was out, Chinese scientists published a formal description of the fossil and gave it a name: Sinosauropteryx, the "Chinese reptilian wing," in honor of its transitional status between dinosaurs and birds.

Sinosauropteryx was the firing gun for a fossil rush, as farmers across Liaoning Province — a bucolic region of fields and rolling hills along the Chinese border with North Korea — fanned out in search of more feathered dinosaurs.

They knew the land better than anyone, and they knew museums would pay top money for such precious fossils. Soon, they were finding feather-covered dinosaurs in droves. The whole area, it turned out, had been bombarded by volcanic eruptions in the Jurassic and Cretaceous Periods, which quickly entombed entire ecosystems.

This was the key to the fine preservation: Normally soft bits like skin and feathers decay before a skeleton can harden into a fossil, but in this one remarkable place, feathers could easily fossilize. It was a dinosaurian Pompeii. As the new millennium dawned, the mounting Chinese discoveries transformed our image of dinosaurs.

One feathered dinosaur became ten, then hundreds, then thousands of skeletons, belonging to several dozen distinct species. Some, like the ostrich-size Beipiaosaurus, were adorned with simple filaments that looked like oversize versions of the bristle feathers of modern birds. Others, like the original Sinosauropteryx, had more complex feathers that resembled little paintbrushes, with many individual bristles branching from a root in an untidy tuft.

Much more extravagant were the feathers of the turkey-size Caudipteryx and dromaeosaurid "raptors" like Sinornithosaurus, which had true quill pens with a central shaft and many barbs extending off the sides to form vanes. Sometimes, these pennaceous feathers lined up along the hand and arm, making what could only be described as a wing, like in the crow-size Microraptor.

The roster of feathered dinosaurs got richer and richer. Even tyrannosaurs were in on the makeover: two early cousins of T. rex called Dilong and Yutyrannus were found coated in bristle and tufty feathers. Most of these plumose dinosaurs were theropods, members of the great group of meat-eaters on the family tree, but a few plant-eaters like Psittacosaurus, a primitive cousin of Triceratops with tiny horns on its head, had mohawks of bristles along their tails.

And most of these feathery fossils were from China, but soon they started to turn up elsewhere, like in Siberia, where a herd of hundreds of dog-size, duck-billed dinosaur cousins called Kulindadromeus were overwhelmed by their own volcano. This herbivore was resplendent with bristles on its head and body, branching downy tassels on its arms and legs, and curi-ous ribbonlike streamers on its knees — while meanwhile there were also scales on the lower legs and tail. Although Kulindadromeus was a vegetarian distantly related to theropods, its branching tufts — each formed by six or seven short filaments arising from a common anchor — look like they could be plucked from Sinosauropteryx or another meat-eater.

Initially, there was some skepticism that these wispy fossilized structures on the backs, tails, and arms of dinosaurs were true feathers. It was a legitimate question when Sinosauropteryx was first unveiled: Could its little strands and bristles have been something else, like degraded skin, or a freak by-product of decay and fossilization?

The discovery of full-on pennaceous quills — with shafts, barbs, and vanes — in species like Caudipteryx and Microraptor proved that many of these were genuine feathers. But what of those simpler filaments in other dinosaurs? We can be confident they are real. They not only look like the bristles and down feathers of birds today, but they share the same structure: They are hollow, chemical analysis shows they are formed of those rare CBP proteins, and when you look at them under powerful microscopes, you see they are full of melanosomes, the minuscule bubbles that hold pigments and give modern feathers their colors.

Still doubt it? Then gander at one of the most improbable fossils ever discovered, from Myanmar, announced in 2016. It's a tail of a juvenile theropod embedded in amber, shrouded in feathers, their details preserved in stunning 3D. Suspended in yellow resin, like a bug frozen into an ice cube, the feathers seem almost alive.

They may as well be bundles of down that slipped out of a pillow and stuck onto your sofa. They have a small central shaft, which branches into barbs, which further branch into barbules. And they are clearly observed growing from follicles in the skin. They are absolutely feathers, and fulfill every definition we use to characterize feathers in modern birds — but they are plastered to a dinosaur.

This bounty of feathered dinosaurs, fundamentally, was that final piece of evidence to verify what has now become paleontological consensus: Today's birds evolved from dinosaurs.

Excerpted from the book THE STORY OF BIRDS: A New History from Their Dinosaur Origins to the Present by Steve Brusatte. Copyright © 2026 by Stephen (Steve) Brusatte. From Mariner Books, an imprint of HarperCollins Publishers. Reprinted by permission.

Scientists have cracked a major mystery about mammal evolution after discovering a 250 million-year-old fossilized egg from before the time of the dinosaurs. Researchers say the specimen, which holds a curled-up embryo of the plant-eating animal Lystrosaurus, is the first known egg ever found from a mammal ancestor, proving that mammals' ancestors laid eggs.

The egg could help paleontologists better understand how these animals survived the Permian-Triassic extinction, also known as the Great Dying, which occurred around 252 million years ago. During this event, Earth faced brutal heat, drought, volcanic eruptions and ocean acidification, and 90% of Earth's species died.

"It reveals how reproductive strategies can shape survival in extreme environments: by producing large, yolk-rich eggs and precocial young, Lystrosaurus was able to thrive in the harsh, unpredictable conditions following the end-Permian mass extinction," Julien Benoit, a paleontologist and associate professor at the University of the Witwatersrand, South Africa's Evolutionary Studies Institute, said in a statement.

The researchers revealed their findings April 9 in the journal PLOS One.

Which came first: the therapsid or the egg?

The fossilized egg was first found in 2008 during fieldwork near the Xhariep municipal district in South Africa. Although the specimen only had small flecks of bone near a nodule, it contained a nearly complete, tightly curled embryo. The researchers identified the animal as Lystrosaurus, an early ancestor of mammals belonging to a group known as therapsids. Therapsids were mammal-like reptiles that lived around 272 million to 250 million years ago that modern mammals descended from.

"The adult [Lystrosaurus] looked like a pig, with naked skin, a beak like a turtle, and two tusks sticking out and pointing down," the researchers wrote for The Conversation.

Scientists have known about this mammal ancestor for years, but they weren't sure whether the animal laid eggs.

Initially, the researchers couldn't determine if the embryo had already been born or was still inside an egg when it died, because the fossil lacked an outer shell and only the embryo was preserved.

"I suspected even then that it had died within the egg, but at the time, we simply didn't have the technology to confirm it," Jennifer Botha, a professor at the University of the Witwatersrand's Evolutionary Studies Institute in South Africa, said in a statement.

For the new study, the researchers used powerful CT scans at the European Synchrotron Radiation Facility in France to study the fossil without damaging it. The scans revealed tiny structures inside the fossil, including an unfused lower jaw, still in two halves. That meant the embryo was not developed enough to feed on its own ‪—‬ a sign that it hadn't hatched yet. The researchers suspect the shell was leathery and dissolved.

"For over 150 years of South African palaeontology, no fossil had ever been conclusively identified as a therapsid egg," Botha said in the statement. "This is the first time we can say, with confidence, that mammal ancestors like Lystrosaurus laid eggs, making it a true milestone in the field."

Putting all the eggs into one surviving basket

The researchers found that Lystrosaurus laid unusually large eggs for its body size. In living animals, large eggs carry more yolk, which can fuel more complete development before they hatch. That finding points to Lystrosaurus having young that were relatively mature and mobile soon after birth, the researchers suggested. This would have made these animals more capable of feeding themselves and avoiding danger, thus helping them survive the Great Dying, the researchers said.

The larger size of the eggs and their leathery texture helped these animals survive in other ways too, the researchers suggested.

"The larger the egg, the smaller its surface area (comparatively speaking), so Lystrosaurus eggs would lose less water through their leathery shell than those of other species of that time," the researchers wrote in The Conversation. "Given the dry environment during and in the immediate aftermath of the extinction, this was a significant advantage, especially since hard-shelled eggs would not evolve for another 50 million years, at least."

While many lineages vanished in the Permian-Triassic extinction event, Lystrosaurus not only survived but became one of the dominant land animals afterward.

"Growing up fast, reproducing young and proliferating were the secrets of Lystrosaurus survival," the researchers added in The Conversation article.

The findings could help scientists understand more about how animals can survive changing climates.

"In a modern context, this work is highly impactful because it offers a deep-time perspective on resilience and adaptability in the face of rapid climate change and ecological crisis," Benoit said in the statement. "Understanding how past organisms survived global upheaval helps scientists better predict how species today might respond to ongoing environmental stress, making this discovery not just a breakthrough in palaeontology, but also highly relevant to current biodiversity and climate challenges."

During the Triassic around 205 million years ago, a newly-identified relative of modern crocodiles stalked its prey, but not in the water, a new study finds.

Like other ancient crocodile cousins, this newly identified species hadn't yet ventured into the water. Instead, it hunted its prey on land, much like a modern fox or jackal, the researchers said.

It would have been a fearsome predator, with its fossil suggesting "specialization for a powerful bite," the researchers wrote in the study.

The specimen was originally discovered decades ago, in 1948 at Ghost Ranch, New Mexico, in a well known dinosaur death bed. At the time, it was tentatively cataloged as a specimen of Hesperosuchus agilis, a small, early relative of crocodiles and alligators. But now, the new study shows that the creature's unusually short snout and thick, reinforced skull set it apart as an entirely new genus and species, though the creature lived — and died — at the same time and place as H. agilis.

"This is the first really strong evidence we have of coexistence between two functionally different-looking crocodylomorphs," study co-author Miranda Margulis-Ohnuma, a paleontologist at Yale University, told Live Science. Crocodylomorphs include modern crocodiles, alligators, caimans and their extinct relatives.

The fossil of the short-snouted creature, newly dubbed Eosphorosuchus lacrimosa, was uncovered in a Late Triassic (237 million to 201 million years ago) formation. The animal's skull, the bones of one of its back legs, one vertebra, and three scales were preserved. The creature would have been about the size of a large dog.

"It was in the basement of the Peabody Museum [at Yale] for, literally, 75 years," Margulis-Ohnuma said. "People would sometimes come visit and look at it, but it had never been identified."

In the new study, published Wednesday (April 15) in the journal Proceedings of the Royal Society B: Biological Sciences, Margulis-Ohnuma and her colleagues categorized the fossil in detail and compared it with a fossil of H. agilis found about 15 feet (5 meters) away. The animals in this section of Ghost Ranch lived at the same time, and they died and were buried in a single event, possibly a flood.

E. lacromisa has a much shorter snout than H. agilis, the team found. It also has a larger, triangular postorbital — a bone in the skull — and matching features on its lower jaw that may have accommodated strong muscles for chomping. Together, those traits suggest the creature had a very powerful bite.

Because E. lacrimosa and H. agilis lived alongside each other, the team suspects they occupied different ecological niches. For example, crocodilians with shorter snouts may have fed on larger, less-agile prey than species with longer snouts did.

"It's really cool that it's not a lineage that's just struggling to take off — at this point, there's already diversity," Margulis-Ohnuma said. "We're really getting a snapshot of the very beginning of functional diversity across crocs."

Scientists don't know much about the early stages of crocodylomorph evolution. There aren't many of these animals preserved in the fossil record, Margulis-Ohnuma said, and many crocodylomorph species from the Triassic are represented by a single fossil specimen.

"For early crocs, we're very data deficient, so every new fossil that comes out is changing the story," Margulis-Ohnuma told Live Science. "If we can continue to describe this material that we have, and ideally find new fossils, it will change the story every single time."

A newly discovered trove of fossils in southwestern China is shifting the timeline of when complex animals evolved.

The diversity and complexity of animal life is thought to have increased rapidly beginning around 539 million years ago, in an evolutionary burst known as the Cambrian explosion. But the new fossil site suggests that some of that complexity was already present several million years before the Cambrian explosion, during the end of the Ediacaran period (roughly 635 million to 539 million years ago).

Among the fossil finds were bilateral worm-like animals that may have anchored themselves to the seafloor, early comb jellies, and relatives of starfish and sea cucumbers that likely used tentacles on their heads to catch food. Other fossils bore little resemblance to modern animals or to known Ediacaran or Cambrian species.

"One specimen looks a lot like the sand worm from Dune," study co-author Frankie Dunn, a researcher who studies Ediacaran organisms at the Oxford University Museum of Natural History, said in a statement.

Some simple multicellular creatures, such as sponges, first appeared during the Ediacaran period. But most modern animal phyla showed up during the subsequent 13 million- to 25 million-year-long Cambrian explosion, including chordates, the phylum that includes humans and other vertebrates.

The new fossil discovery suggests that some of that complexity had already arisen by the late Ediacaran. Uncovered as part of the Jiangchuan Biota collection of fossils in southwestern China, the collection contains more than 700 specimens of fossilized animals and algae dating to between 554 million and 539 million years ago. Researchers reported the findings Thursday (April 2) in the journal Science.

"When we first saw these specimens, it was clear that this was something totally unique and unexpected," study co-author Luke Parry, a paleobiologist at the University of Oxford, said in the statement.

The fossils from this site are mostly flat imprints of the organism on the surrounding rock, known as carbonaceous films. Unlike the three-dimensional imprints left by durable body parts, such as bones and shells, carbonaceous films capture some details of the organism's soft tissues, such as its gut and mouthparts.

This less-common method of preservation might help to explain why scientists haven't found evidence of these more complex animals in the Cambrian until now.

"Our results indicate that the apparent absence of these complex animal groups from other Ediacaran sites may reflect differences in preservation rather than true biological absence," study co-author Ross Anderson, a researcher who studies the evolution of complex life at the Oxford University Museum of Natural History, said in the statement. "Carbonaceous compressions like those at Jiangchuan are rare in rocks of this age, meaning that similar communities may simply not have been preserved elsewhere."

While exploring a cave in central Texas, scientists unearthed a long-lost ice-age ecosystem, including the remains of a giant tortoise and a lion-size armadillo relative, among a trove of fossils in an underground stream.

In a study published March 19 in the journal Quaternary Research, researchers say the cave may preserve the remains of animals that lived during a relatively warm period of the last ice age. If the findings are validated, the site would offer a rare look at an animal community that was missing from central Texas' fossil record.

"It blew my mind," lead author John Moretti, a vertebrate paleontologist in the University of Texas at Austin's Jackson School of Geosciences, told Live Science. "Just the abundance of fossils and the animals those fossils represent were really exciting."

Moretti and John Young, a local caver, were exploring Bender's Cave, near San Antonio, in 2023, when they came across the fossils. The cave is difficult to access and has a subterranean stream running through it, so it had largely been ignored by paleontologists. However, they suspected fossils were present, as amateur cavers had previously brought in their finds, Moretti said.

It was Moretti and Young who found the ice-age fossils simply lying in the mud.

"We have bags attached to our waists, and we're picking up fossils as we go," Moretti said. Over six trips between 2023 and 2024, Moretti and Young discovered fossils from 21 areas in the cave. Among the finds were a claw from a giant sloth (Megalonyx jeffersonii), mammoth teeth, and bones of camelids (Camelops), the long-legged ancient relatives of modern day llamas.

But what really intrigued them was the discovery of fossils of two ice-age beasts: a pampathere (Holmesina septentrionalis), a giant armadillo relative that lived during the middle to late Pleistocene (781,000 to 126,000 years ago) ; and an extinct genus of giant tortoise (Hesperotestudo).

The discovery of these two fossilized animals puzzled Moretti and Young because these ice-age giants were not known to have lived in this area. For more than a century, researchers have studied ice-age fossil sites in central Texas and built a picture of the region during that time as a dry grassland dominated by grazing animals. According to Moretti, this climate would not have been suitable for the tortoise or the pampathere.

Moretti and Young suggested that the animals' remains washed into the cave system from the surface through sinkholes during floods and then settled on the streambed. If this is the case, the animals may have lived during a warmer interglacial period, roughly 100,000 years ago, when temperatures rose and animals that favored milder conditions moved into the region, the researchers proposed.

Moretti said they have not been able to accurately date the bones because the collagen proteins often used as the biomarker in fossils were completely eroded by the mineral-rich water. This water also contaminated many of the fossils, as the bones absorbed carbon and other minerals after being deposited. This means a test may measure this contamination rather than the fossils' true ages.

To overcome this challenge, the team is now trying to date the calcite crusts that formed on the bones after they entered the cave. Although these results won't provide exact dates for the fossils, they can set a minimum age for when they were deposited. With these dates, the researchers hope to narrow down whether the cave fossils represent a warmer interglacial chapter of Texas' history.

"We still don't know everything about the natural world," Moretti said. "There's still a lot to discover out there."

Think you know all about the ice age? Test your smarts with our mammoth quiz!

Paleontologists have revealed a bizarre prehistoric creature with a twisted jaw and sideways-facing teeth, and the water-dwelling weirdo was already a "living fossil" when it existed 275 million years ago.

The newly described species, named Tanyka amnicola, is an archaic member of the tetrapods — a large group of four-limbed vertebrates that today includes reptiles, birds, mammals and amphibians, according to a study published Wednesday (March 4) in the journal Proceedings of the Royal Society B.

Despite predating the dinosaurs, T. amnicola was already an evolutionary relic in its time, during the Permian period. Many of the earliest tetrapod lineages, known as stem tetrapods, had already disappeared by that time. But the lineage that T. amnicola belonged to seems to have persisted, while tetrapods as a group were diversifying.

"Tanyka is from an ancient lineage that we didn't know survived to this time, and it's also just a really strange animal," lead study author Jason Pardo, a research associate at the Field Museum in Chicago, said in a statement. "In the sense that Tanyka was a remaining member of the stem tetrapod lineage, even after newer, more modern tetrapods evolved, Tanyka is a little like a platypus. It was a living fossil in its time."

Researchers identified the new species from nine fossilized lower jawbones, each roughly 6 inches (15 centimeters) long, recovered from a dry riverbed in northeastern Brazil. Although the creature's lower jawbones were distinctive enough for the team to determine the fossils represented a new species, the lack of other fossilized remains means much about the animal remains unknown.

Given what is known about its close relatives, however, T. amnicola might have resembled a salamander with a slightly longer snout. It possibly measured up to around 3 feet (around 91 centimeters) in length, Pardo said. The type of rocks in which the fossils were found also indicate that the creature lived in lake environments and presumably had "aquatic habits," according to the paper.

Analysis of the lower jawbones revealed some intriguing features — principally, that they were twisted so that the creature's teeth pointed outward to the sides, rather than upward as seen in virtually all other tetrapods.

"The jaw has this weird twist that drove us crazy trying to figure it out," Pardo said. "We were scratching our heads over this for years, wondering if it was some kind of deformation. But at this point, we've got nine jaws from this animal, and they all have this twist, including the really, really well-preserved ones. So it's not a deformation, it's just the way the animal was made."

Furthermore, the inner surface of the lower jawbone, which faces the tongue in humans, was rotated upward; it was covered in a "remarkable" set of small, teeth-like structures called denticles that would have formed a grinding surface, according to the study. These features suggest the animal had a "relatively unique way" of feeding, Pardo said.

The authors suspect that T. amnicola was adapted to munching on small invertebrates or, potentially, some plant material. This would be unusual, given the lack of evidence for plant-eating or omnivorous diets in other stem tetrapods, which are thought to have been carnivores, the team said.

When T. amnicola lived, Brazil was part of the supercontinent Gondwana. According to the statement, the discovery provides a window into Gondwana's animals during this period. "Tanyka is telling us about how this community actually worked, how it was structured, and who was eating what," study co-author Ken Angielczyk, a curator of paleomammalogy at the Field Museum, said in the statement.

Around 95 million years ago, a Spinosaurus dinosaur with a tall, blade-like crest on its head and a large sail on its back lived in what is now Niger, a new study finds.

The newfound species, which the researchers have named Spinosaurus mirabilis ("astonishing Spinosaurus" in Latin), lived far inland, in river country — which could be the key to settling a debate about whether this dinosaur and its relatives were swimmers, the team reported Thursday (Feb. 19) in the journal Science.

"There's just no way that you're going to find … essentially an aquatic animal hundreds of miles from the shoreline, buried … right in a river deposit," study first author Paul Sereno, a paleontologist at the University of Chicago who led the team that found the fossil, told Live Science.

Sereno's team made the discovery thanks to a Tuareg guide, a member of a local nomadic population that live in the Sahara Desert, who led them to the remote site on an hours-long trek back in 2019. Upon seeing the fossils, the paleontologists noted a peculiarity: The bones were black, caused by an increased concentration of phosphate in the bone. Sereno said that, in his 25 years of fieldwork, he'd never seen fossils that color in the Sahara Desert.

The crest points to a new species

At first, Sereno and the team couldn't figure out how some of the bones fit together with the rest of the skeleton. "We didn't recognize the crest," Sereno said." It was just so weird [and] asymmetrical."

When a larger team returned to the same site in 2022 and uncovered a skull with a partial crest attached, it all clicked. While running CT scans of the fossil and using computer models, the team found lots of fossilized blood vessels inside, plus a surface texture that suggested a keratin sheath covered the bone in real life, which would have made the crest stand up to 20 inches (0.5 meters) tall.

In the paper describing their findings, the researchers called it the tallest crest known in any meat-eating dinosaur and argued it played a decorative role, possibly allowing the animal to identify potential mates or rivals while wading along riverbanks.

So … was Spinosaurus a swimmer?

In recent years, some researchers have argued that Spinosaurus — a genus that includes S. mirabilis, as well as its relatives, such as S. aegyptiacus — chased prey underwater as a marine hunter. For instance, S. mirabilis has the iconic teeth of a fish hunter, with those on the lower jaw protruding outward and fitting neatly between the sharp teeth on the upper jaw, the team reported.

Yet, based on the fossil's location — buried next to two long-necked sauropods in a river bed, and its body shape — Sereno sees "this dinosaur as a kind of ‘hell heron’ that had no problem wading on its sturdy legs into two meters [6.5 feet] of water but probably spent most of its time stalking shallower traps for the many large fish of the day,” he said in a statement.

The back sail would have added so much weight to Spinosaurus' body that it would have made it difficult to move, Sereno noted. So it's unlikely that any members of the genus swam, he said. "It's sacrificing … aspects of its agility for this, but it's an important feature," Serano told Live Science.

In the paper, the researchers compared S. mirabilis' body shape with other living and extinct predators and placed it between semiaquatic waders like herons and aquatic divers like penguins.

"It shows the process of science evaluating evidence and new evidence appearing," Sereno said.

T. rex quiz: How much do you really know about the king of the dinosaurs?

Our oldest known vertebrate ancestors had four eyes to spot predators — and, my goodness, they were cute.

Rare fossils from China have revealed that the earliest recorded creatures with spines — jawless fish from half a billion years ago — were equipped with two sets of peepers. Researchers have released an adorable reconstruction of one such four-eyed noodle as part of a study that described the two pairs of eyes, which were surprisingly advanced for their time.

"This changes how we think about the early evolution of vertebrates," study co-author Jakob Vinther, an associate professor in macroevolution at the University of Bristol in the U.K., said in a statement. "It turns out our ancestors were visually sophisticated animals navigating a dangerous world."

Humans come from a long line of vertebrates that researchers can trace back to these jawless fish, called myllokunmingids. Most of our relatives have two eyes just as we do, but it seems myllokunmingids needed more.

Myllokunmingids lived 518 million years ago, during the Cambrian period (541 million to 485.4 million years ago). During this time in Earth's history, large predators were beginning to emerge, making the ocean more dangerous for our small, soft-bodied ancestors.

"In that environment having four eyes may have given these animals a wider field of view — important to avoid predators," Vinther said.

Researchers discovered the eyes in exceptionally detailed fossils preserved in the Chengjiang fossil beds in southern China. In two separate species — Haikouichthys ercaicunensis and an unnamed myllokunmingid species — fossils were found to have two larger eyes on both sides of their heads and two smaller eyes in the middle of their heads, according to the study.

Because soft body parts like eyes are rarely preserved in the fossil record, the researchers were fortunate to find the remains of any eyes in the fossils, let alone four. To confirm the existence of the eyes and examine their structure, the team used high-powered microscopes and chemical analysis.

"We started by examining the obvious large eyes to understand their anatomy — and it was a complete surprise to find two smaller, fully functional eyes between them," study lead author Peiyun Cong, a research professor of paleobiology at Yunnan University in China, said in the statement. "Seeing that was incredibly exciting."

The two smaller eyes were circular, with light-absorbing pigments and lenses that could form images, just like the larger eyes, according to the researchers. The team thinks the second pair of eyes represents the ancestral origins of a more primitive eye-like feature in some modern vertebrates and a gland, which, in humans, helps us sleep.

Some living fish, reptiles and amphibians have a parietal eye, or "third eye," on their heads that detects light only. This parietal eye is tied to the pineal gland, which, in humans and most other vertebrates, is located in the brain. The pineal gland produces the hormone melatonin when it's dark, which, in turn, helps us fall asleep. But half a billion years ago, the precursor to this gland was helping myllokunmingids escape predators.

"What we're seeing is that the pineal organs began as image-forming eyes," Cong said. "Only later in evolution did they shrink, lose visual power, and take on their modern role in regulating sleep."

Researchers have uncovered an intriguing set of never-before-seen features in the skull of Archaeopteryx, an iconic dinosaur that is considered a key transitional fossil in the evolution of birds, a new study reports.

The features — which are absent in nonflying dinosaurs but are widespread in living birds — may have enabled Archaeopteryx to acquire, manipulate and process food more efficiently, the research team proposed in the study, which was published Feb. 2 in the journal The Innovation.

The newly discovered features include a tiny bone that indicates Archaeopteryx had a highly mobile tongue. The researchers also identified "weird" soft tissue traces interpreted as oral papillae — small, tooth-like projections on the roof of the mouth, Jingmai O'Connor, an associate curator of fossil reptiles at the Field Museum in Chicago and lead author of the study, told Live Science in an email. Finally, the team found "unusual" openings near the tip of Archaeopteryx's jaw that suggest a nerve-rich structure and may represent an early analogue of what is known as a bill-tip organ in modern birds.

The identification of these features in Archaeopteryx marks their earliest known appearance in the fossil record, according to the study, suggesting these characteristics evolved during or close to the emergence of avian dinosaurs — known as birds — which is thought to have occurred during the Late Jurassic period (roughly 161.5 million to 143 million years ago).

Modern birds are the only dinosaur lineage that survived the mass extinction event 66 million years ago. Archaeopteryx, which lived around 150 million years ago in what is now Germany, is among the oldest — if not the earliest — known dinosaur that can also be considered a bird under a broad definition, although it was probably not the first bird to evolve, O'Connor said.

Furthermore, Archaeopteryx is unlikely to have been a direct ancestor of modern birds, research suggests. According to O'Connor, Archaeopteryx represents the earliest known dinosaur with good evidence for active, feather-driven flight, although this was likely limited to brief, powered bursts.

The newly revealed features came to light during the preparation and examination of an Archaeopteryx specimen at the Field Museum that was first described scientifically in 2025.

Oral papillae help birds grip prey and guide food down their throats. This is the first time such features have been documented in the fossil record, the study noted. The flexible tongue, meanwhile, likely would have helped Archaeopteryx reach for food and manipulate it. Bill-tip organs in birds provide "added sensory information" that helps with a variety of oral tasks, such as rummaging around for food, O'Connor said.

The latest findings about Archaeopteryx, which indicate a change in dinosaur feeding abilities occurring around the origin of birds, raise the "interesting possibility" that the evolution of the novel features was driven by the increased energy demands associated with the emergence of powered, feather-driven flight, the authors propose.

Christian Foth, a paleontologist with the Museum für Naturkunde (Natural History Museum) in Berlin who was not involved in the study, told Live Science in an email that the paper has some "interesting findings" that should be explored further in other Archaeopteryx, early-bird and bird-like-dinosaur specimens. But he said he was not convinced by the authors' proposal for a new bill-tip organ analogue in the snout, and urged caution over the suggestion that the features evolved as adaptations to Archaeopteryx's flying behavior.

"Active flight requires energy, correct. But how many calories the animal in the end could use for flight depends more on the diet source itself and the digestion system, which we do not have any info on," Foth said. These adaptations may "ensure that a caught dragonfly did not fall out of the mouth," he added, "but not how well the diet was processed."

Rock climbers in Italy stumbled across evidence of what appears to be a sea turtle stampede that took place nearly 80 million years ago. Now, new research suggests these ancient marine reptiles were fleeing an earthquake.

The climbers recognized the significance of their find because the grooves in the rock face on Monte Cònero overlooking the Adriatic Sea reminded them of others that had made headlines earlier that year. Those grooves had been found in another part of the same regional park and were attributed to a Cretaceous marine reptile pressing its paddles into the seafloor. They consulted with fellow-climber and geologist, Paolo Sandroni, who got in touch with Alessandro Montanari, director of the Coldigioco Geological Observatory (OGC).

After an investigation into what these grooves might be, researchers revealed their findings in a study published Nov. 19 in the journal Cretaceous Research.

Sandroni and another member of the team climbed back to the area to collect rock samples and document the site using a drone.

Hundreds of these tracks are located on a layer of the Scaglia Rossa limestone in Cònero Regional Park, a formation that has been extensively studied for decades and preserves millions of years of deep sea sedimentation, study co-author Montanari told Live Science.

What is now part of a mountain was once a deep seabed folded over and thrust upward by tectonic forces millions of years ago, he said. Rock samples collected immediately above the tracks and analyzed by the team reveal important clues about the tracks’ location and the story behind them. For example, they suggest the sea turtles lived around 79 million years ago during the Late Cretaceous Period and indicate that the limestone was part of an underwater avalanche of mud triggered by an earthquake.

Abundant seismic activity in this formation is also supported by decades of collective study. Thin sections slides of the rock samples reveal microfossils of organisms that live along the seafloor, suggesting a hundreds-of-meters deep seafloor environment.

Normally, any traces left by animals would be erased by currents at the sea bottom and "worms, clams and [other] benthic organisms," Montanari said. "They basically garden the seafloor," he noted. But an earthquake caused an underwater avalanche within minutes of the tracks being made, preserving them, he said.

The only vertebrates big enough to make these tracks in the Late Cretaceous were marine reptiles such as sea turtles, plesiosaurs and mosasaurs. The latter two are believed to have been largely solitary, but, if ancient sea turtle behavior mirrored that of some of today's species, the researchers said, then it is possible they may have foraged near shore or left the water to lay their eggs. Whatever brought them together, an earthquake caused them all to flee at once, the team suggested in the study, forcing some of the turtles to swim in the water above toward the open sea, and others to scurry away closer to the deeper seafloor. The impending underwater avalanche propelled them even further out of the way.

Michael Benton, professor of vertebrate palaeontology at the University of Bristol in the U.K., who was not involved in the research, said the study clearly shows the geological context, but he questioned which animal made the tracks.

"The tracks are unusual because they seem to show underwater punting, where the two forelimbs enter the sediment together and the animal pushes forward," he told Live Science. Most vertebrates tend to “walk or swim with the limbs out of sequence” rather than putting two limbs down at the same time, he said. "Marine turtles generally have a very efficient swimming mode," he said, “a bit like underwater flying, where the front paddles swing round” similar to a figure eight pattern, which doesn’t appear to match the tracks found. He also questions why they wouldn't simply "leave the sea bed and swim" away.

Montanari said that while the prints would benefit from further research, it is clear, geologically, that there was an underwater avalanche triggered by an earthquake. He said he hopes their work will prompt fossil experts to further study the site.

The fearsome Tyrannosaurus rex is perhaps the most iconic dinosaur that ever lived. Ever since the discovery of the first T. rex fossil in Hell Creek, Montana, in 1902, this gigantic predator — with its terrifying teeth and strangely tiny arms — has fascinated people of all ages, and played a starring role in books and films, including the Jurassic Park movies, as well as taking pride of place in museums around the world.

Yet, our picture of how this dinosaur looked and lived has changed markedly thanks to more than a century of scientific discoveries. Think you know everything there is to know about the king of the dinosaurs? Well, start the quiz below to find out if your knowledge is dino-mite or a faded fossil.

Remember to log in to put your name on the leaderboard; hints are available if you click the yellow button!

Editor's note: This article was updated on Jan. 8 at 5:00 a.m. ET to correct a conversion in a question answer.

More science quizzes

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Scientists have discovered an enormous species of duck-billed dinosaur that lived in what is now New Mexico about 75 million years ago.

The dinosaur, Ahshislesaurus wimani, likely had a flat head and a bony crest low on its snout, researchers revealed in a study. The findings, which is due to be published in the Bulletin of the New Mexico Museum of Natural History and Science, suggest that duck-billed dinosaurs, or hadrosaurids, were more diverse and overlapping during the last 20 million years of the Cretaceous period (145 million to 66 million years ago) than previously thought.

Hadrosaurids were large, plant-eating dinosaurs that lived during the last 24 million years of the Cretaceous. They have "sometimes been colorfully called 'the cows of the Cretaceous,'" study co-author Steven Jasinski, a paleontologist at the Harrisburg University of Science and Technology in Pennsylvania, said in a statement. "While this may not be a perfect metaphor, they likely were living in herds and would have been conspicuously present in the environments of northern New Mexico near the end of the Cretaceous."

According to the statement, A. wimani could potentially have grown up to 40 feet (12 meters) long.

One set of A. wimani fossils discovered in 1916 were previously identified as a member of the hadrosaurid genus Kritosaurus. But existing fossil specimens are frequently being reevaluated as more data and fossils become available.

In the new study, the researchers revisited that set of fossils — including an incomplete skull, lower jawbone, and several vertebrae — from the Kirtland Formation in New Mexico. The fossils were housed at the Smithsonian National Museum of Natural History.

"As a general rule … skulls are really the basis for identifying differences in animals," study co-author Anthony Fiorillo, the executive director of the New Mexico Museum of Natural History and Science, said in a separate statement. "When you have a skull and you're noticing differences, that carries more weight than, say, you found a toe bone that looks different from that toe bone."

By comparing the skull to those of other hadrosaurids, the team found that its shape and features were distinct enough from other hadrosaurid skulls to suggest it was likely a different species. A. wimani is closely related to Kritosaurus, suggesting that their evolutionary lines had split not long before.

"Kritosaurus is still a valid genus with species of its own," study co-author Edward Malinzak, a paleontologist at Penn State University Lehigh Valley, said in the second statement. "We took a specimen that was lumped in as an individual of Kritosaurus and determined it had significantly distinct anatomical features to warrant being its own genus and species."

It's not clear yet how the related species co-existed in the same environment, the researchers wrote in the study. But tracing the history and extent of different species could help scientists understand the environment they lived in, as well as the evolutionary history of duck-billed dinosaurs.

"The lineages appear to have co-existed in the region for a time," Malinzak said. "It showed that this group not only exploded with diversity across the continent at one point, but also contributed to the world-wide spread of this group in the Late Cretaceous."

Around 125 million years ago, a dinosaur longer than a pickup truck stalked rivers to gobble up fish in what is now Thailand.

The remains of the roughly 25-foot-long (7 to 8 meters) dinosaur, which include parts of its spine, pelvis and tail, represent one of the most complete spinosaurid specimens ever found in Asia, according to researchers.

Spinosaurids were a family of bipedal predators with elongated snouts, crocodile-like teeth and, in many species, sails on their backs. Researchers believe that the Thai specimen, first discovered in 2004, belonged to the Spinosaurinae subfamily, which included the longest-known carnivorous dinosaur genus, Spinosaurus — a potential swimming predator from North Africa that grew up to around 50 feet (15 m) long.

"This discovery from Thailand helps us better understand what spinosaurines looked like and how they evolved in Asia," Adun Samathi, an assistant professor at the Walai Rukhavej Botanical Research Institute and Mahasarakham University in Thailand, told Live Science in an email. "[The fossils] also show that dinosaur diversity in Southeast Asia was richer than previously known and expand our understanding of how these unusual fish-eating predators were spread around the world."

Samathi presented the spinosaurid findings Nov. 12 at the Society of Vertebrate Paleontology 2025 annual meeting in Birmingham, England. The findings haven't been peer-reviewed, as Samathi and his colleagues still have to submit them to a journal.

The researchers don't have an official name for the dinosaur. However, they've nicknamed it the Sam Ran spinosaurid, as it was found in the Sam Ran locality (area) of the Khok Kruat rock formation in northeastern Thailand, according to Samathi, who studied the spinosaurid as part of his doctoral thesis. (Samathi is one of several students and researchers to study the specimen since its discovery.)

The team quickly identified the dinosaur as a spinosaurid because it has several of the group's characteristic features, including long neck vertebrae and tall spines on its back vertebrae. However, the species also had features that distinguished it from known spinosaurid species, including shorter spines than Spinosaurus and more paddle-like spines than Ichthyovenator from Loas, which borders Thailand.

The team suspects that the Sam Ran spinosaurid was more closely related to Spinosaurus from North Africa than Ichthyovenator from Laos. However, there's a lot of uncertainty surrounding the evolution of Asian spinosaurids, as well as spinosaurids in general, and the researchers' findings are only preliminary at this stage.

The Sam Ran spinosaurid died beside a shallow river before some of its remains were fossilized. Samathi doesn't think that this spinosaurid could swim, but it seemed to be using the river ecosystem, which was teeming with life when the dinosaur perished relatively early in the Cretaceous period (145 million to 66 million years ago).

"The new spinosaur lived (or at least [was] found) in a river system with gently flowing water and occasional floods, within a dry to semi-arid landscape," Samathi said. "The site has yielded a variety of animals, including freshwater sharks, bony fish, turtles, crocodiles, and dinosaurs such as a sauropod and an iguanodontian."

More than 5,000 years ago, burrowing bees made their homes inside heaps of rodent bones buried in a cave on Hispaniola, the Caribbean island that comprises the Dominican Republic and Haiti, a new fossil study suggests.

The bees encountered the bones while digging to their preferred depth in the soil. They stopped to build nests inside tooth and vertebra cavities, which turned out to be the perfect size, researchers found. Most of the bones the scientists recovered were from hutias — chunky rodents that look like a cross between squirrels and beavers — but a handful were the remains of an extinct type of sloth.

This is the first time that bee nests have been discovered inside preexisting nooks in fossils and only the second piece of evidence of burrowing bees nesting in a cave. Researchers previously documented examples of bees drilling into old bones to make their nests, but the new find suggests the bees readily settled in existing fossil cavities, according to the study, which was published Wednesday (Dec. 17) in the journal Royal Society Open Science.

"The cells of Osnidum almontei [the name given to the fossilized nests] appear highly opportunistic, filling all bony chambers available in the sediment deposit," the researchers wrote in the study.

The bees found the hutia bones a long time after they were deposited in the cave by Hispaniolan barn owls (Tyto ostologa), the researchers posited. Evidence shows that these owls, which are now extinct, sometimes transported hutias into the cave whole, discarding the bones as they devoured the rodents, and sometimes regurgitated pellets containing the remains of hutias they had eaten while hunting. Barn owl bones found in the cave indicate the species lived there, the researchers noted.

These piles of bones became buried over time as sediments washed into the cave from outside. And several generations of burrowing bees took advantage of this much later, even though these bees typically make their nests in the open, according to the study.

In one tooth cavity, the researchers found six nested bee nests, indicating that successive generations made their homes in the same spot after previous nests had been abandoned.

The bees may have chosen to nest in the cave rather than outside it because the surrounding landscape had little to no earth for burrowing. "The area we were collecting in is karst, so it's made of sharp, edgy limestone, and it's lost all of its natural soils," study co-author Mitchell Riegler, a teaching assistant at the University of Florida, said in a statement.

After one of the scientists' last visits to the cave, plans had been submitted to turn it into a septic storage facility.

"We had to go on a rescue mission and get as many fossils out as possible," study lead author Lazaro Viñola Lopez, a paleobiologist at the Field Museum of Natural History in Chicago, said in the statement.

The plans to build a septic tank eventually fell through, but the scientists removed abundant fossils regardless. These fossils have yet to be analyzed, and the team plans to publish more studies about their finds.

Scientists have discovered a record-breaking number of fossilized dinosaur footprints and swim tracks in a national park in central Bolivia.

The tracksite sits along what was once an ancient coastline, with ripple marks extending alongside the footprints and other imprints in a northwest-southeast direction, according to a new study. Most of the tracks belong to bipedal, three-toed dinosaurs known as theropods that lived at the end of the Cretaceous period (145 million to 66 million years ago), but many bird tracks are also preserved, the scientists noted in the paper, which was published Wednesday (Dec. 3) in the journal PLOS One.

"This is the highest number of dinosaur footprints ever found for a single tracksite thus far," study co-author Jeremy McLarty, a paleontologist and associate professor at the Southwestern Adventist University in Texas, told Live Science in an email. "In addition to preserving the most dinosaur tracks worldwide, it also preserves the highest number of swim trackways in the world."

In total, McLarty and his colleagues counted 16,600 theropod footprints and 1,378 swim tracks. These were found in Bolivia's Carreras Pampa tracksite, which was already known but hadn't been properly studied or documented.

Carreras Pampa extends across 80,570 square feet (7,485 square meters) in Torotoro National Park. The initial work involved sweeping debris off the dinosaur imprints with brooms, clearing the tracksite of rocks and removing sediment in places where additional tracks were likely to be found.

The team discovered a huge variety of footprint shapes and sizes, indicating that many types of theropod dinosaurs roamed along the ancient coastline. Several tracks had footprints shorter than 4 inches (10 centimeters), which is rare in the fossil record, according to the study. It's unclear if these footprints were made by small theropod species such as Coelophysis or by juveniles of larger species, the researchers wrote.

The largest footprints were more than 12 inches (30 cm) long, and the team thinks these may have been made by mid-size theropod dinosaurs such as Dilophosaurus or Allosaurus. Large theropods such as Tyrannosaurus rex and Giganotosaurus typically leave 16-inch-long (40 cm) footprints, the researchers noted.

Carreras Pampa is unique because the footprints show different dinosaur behaviors, such as walking, running, swimming, tail-dragging and making sharp turns. "It preserves evidence of several types of unusually preserved locomotive behaviors, and preserves one of the highest numbers of dinosaur tail traces anywhere in the world," McLarty said.

The swim tracks are straight or comma-shaped grooves that often have one or two similar but smaller grooves next to them, McLarty said. The main groove is from theropods scratching the sediment at the bottom of the water with their middle toe, while the smaller grooves are from the other toes. Unlike other sites that preserve only individual dinosaur swim tracks, Carreras Pampa preserves alternating left and right tracks, he said.

The abundance of imprints shows that Carreras Pampa was a prehistoric highway, and the parallel orientation of some trackways suggests some dinosaurs traveled in groups.

Bolivia is known for being a dino track hotspot.

"The tracksite with the next highest number of tracks is also in Bolivia," McLarty said. "The Cal Orck'o tracksite is located in an active quarry as a nearly vertical wall and is long and thin. The Carreras Pampa tracksite is spread out across a wider area."

Ancient footprints have revealed that large, bone-crushing dogs stalked the ashy wastes of North America in the wake of a devastating Yellowstone supereruption 12 million years ago.

Researchers uncovered the footprints above the skeletons of extinct rhinoceroses called Teleoceras in the Ashfall Fossil Beds of northeastern Nebraska. The dog tracks mark the first direct evidence of large carnivores in the beds, which are nicknamed "Rhino Pompeii" because they have preserved so many Teleoceras rhinos that perished in widespread fallout from volcanic activity at Yellowstone.

"The eruption was so massive that ash would have fallen like snow 1,000 miles [1,600 kilometers] from the eruption site in Idaho," Ashley Poust, a curator of vertebrate paleontology at the University of Nebraska State Museum, told Live Science. "This would have darkened the skies, buried plant life and water sources, and been a real hazard to anything with a delicate respiratory system."

Ancient horses, giraffe-like camels, numerous rhinos and various other animals were entombed in glass-like ash at the Nebraska site. However, until the footprint discovery, researchers hadn't found hard evidence of large meat eaters in the beds, which is unusual, given the abundance of preserved prey.

The footprints were up to 3.2 inches (8 centimeters) long and 3 inches (7.5 cm) wide, matching those of the large, extinct canids Aelurodon taxoides and Epicyon saevus, which crushed and ate bones like modern hyenas do. Not only do the footprints confirm the presence of large carnivores in the beds, but their positioning above the rhino layers suggests that the dogs survived the cataclysmic event that wiped out many animals.

"Survival of top predators after ecological collapse is a little unexpected and has a lot to teach us about how life responds and recovers after disasters," Poust said. Big predators sit at the top of the food chain, so they normally starve if it collapses.

Poust presented preliminary findings from his research Nov. 12 at the Society of Vertebrate Paleontology 2025 annual meeting in Birmingham, England. The findings haven't been peer-reviewed yet, as Poust and his colleagues still have to complete their research and submit it to a journal.

The clearest trackways were uncovered in 2014 and 2023, according to the researchers. While the footprints have yet to be formally described in a journal, their existence isn't a secret. Poust said people visiting the Ashfall Fossil Beds State Historical Park can see the footprints, and his team has subjected the tracks to laser scanning within the public's view. Epicyon is also listed on the University of Nebraska State Museum's ashfall animals webpage.

Northeastern Nebraska once had a similar environment to the African plains. Poust noted that the Ashfall Fossil Beds preserved a seasonal lake that hosted aquatic life, like turtles, and attracted all manner of animals.

"Imagine a watering hole similar to those on the savanna today, but with slightly unfamiliar animals," Poust said. "The sandy shoreline would have been shared by flocks of birds and herds of short-legged rhinos, camels, and five species of horses, some with three toes on each foot."

The dog tracks are present in multiple ash layers and point in different directions, which Poust and his colleagues say is an indication that the predators were making extended or repeated visits to the area after it was caked in volcanic fallout.

It's not yet clear how the dogs were surviving at the time, but one possibility is that they fed on buried rhinos and other carcasses in the immediate aftermath of the eruption.

"There is some evidence that they may have scavenged among the animals who didn't survive, using the buried rhinos as a food cache," Poust said. "But since we haven't found the bones of these meat eaters, we aren't sure yet whether this was enough to see them through to better times, or whether they eventually had to depart to seek their fortunes elsewhere in the massive disaster zone that covered much of North America."

A stunning new animation shows saber-toothed cats attacking a herd of woolly mammoths toward the end of the last ice age in the frozen north of North America.

Airing Wednesday (Nov. 26) in an episode of Apple TV's upcoming series "Prehistoric Planet: Ice Age," the clip explores how iconic ice age animals adapted to changes in their environment as the climate began to warm and their snowy world gradually disappeared. In the video, a pack of five scimitar-toothed cats (Homotherium serum) — a now extinct species of saber-tooth cat — ambush a herd of woolly mammoths (Mammuthus primigenius) that includes a tiny calf and a large adult male.

"That whole story is set in the frozen north, sort of Alaska-Yukon," Mike Gunton, executive producer of the upcoming series and creative director of BBC Studios' Natural History Unit in the U.K., told Live Science in an email. "Those creatures both were sort of stars of the Ice Age, hyper-adapted to life in the cold. The story really is about what happens when those two types of animals are finding their world changing."

As the last ice age drew to a close about 11,500 years ago, ice sheets retreated across North America. This drove some species into extinction, as did hunting from humans living in the Americas at the time, reducing the animal populations that scimitar-toothed cats preyed on. "The prey that they would normally feed on are not around as much as they were," Gunton said. "The fortune of that day is that the cats find a herd of mammoths coming into their pack, and they take the opportunity to try and hunt them."

Woolly mammoths also struggled to survive at the end of the last ice age, and the clip shows the herd taking an unusual route across a plain to find new feeding grounds, Gunton said. Exposed — as they are in the clip — the mammoths come under attack. After a nail-biting few seconds where a scimitar-toothed cat leaps onto the male mammoth and hangs off his trunk by the claws, the mammoth overpowers the five cats and scares them off.

Meanwhile, the females and the calf retreat, huddle together and watch the scene unfold. While researchers think that woolly mammoth herds were female-led and males dispersed at a young age, sexually-mature males occasionally joined herds to mate, Gunton said.

"These males have what they call [musth] — they have these glands on the temporal area of their skulls, and they weep, producing particular pheromones — and that gets everybody excited," he said. "This mammoth was with them [in the clip] because you get males coming to join a herd with the idea of mating with the females, and they will spend a lot of time wandering around with them."

The mammoths survive this encounter, but the scimitar-toothed cats eventually triumph in a sequence later in the show, Gunton said.

"At the end of the program, we see them trying again with [a] different strategy," he said, adding that one of the cats lunges off a high rocky outcrop onto the back of the male mammoth, giving the other cats the opportunity to pile on and take the mammoth down. "And then they feed," Gunton said.

The hunting technique of scimitar-toothed cats in the second clip is similar to that of leopards, which also leap onto their prey from above, Gunton said. Recreating these attacks was a big challenge for the filmmakers, because "you've got two animals created in visual effects actually interacting with each other," he said.

A bigger challenge still was making the animals appear realistic, given that they are covered in fur and moving in a snowy landscape.

"Every one of those creatures will have millions of individual little hairs on it, all of which behave on their own independently," Gunton said. "Then they're doing stuff in snow, so you've got complex interactions between snow itself. It's sort of the pinnacle of what is tough to do in this series."

Read more | How to watch 'Prehistoric Planet' – Streaming details as new season 'Ice Age' lands on Apple TV

For the first time, scientists have successfully sequenced woolly mammoth RNA, shattering the assumption that this fragile genetic molecule couldn't survive from so long ago.

RNA, or ribonucleic acid, carries instructions between DNA and an organism's protein-building machinery, acting as a messenger to turn genetic information into proteins. RNA can reveal which genes are active in a cell at a given moment, as well as how gene-activity patterns within a cell change over time. Thus, ancient RNA can inform scientists about the cellular states of extinct species.

Although the technology behind ancient DNA research has surged over the past 20 years, ancient RNA research has seen few successes. This is due in part to its construction, as DNA molecules are double-stranded and therefore sturdier than the single-stranded RNA.

While DNA offers the blueprint of an organism, there are limits to the information it reveals. RNA "opens a window into how" that blueprint is implemented within each cell of the organism, said study co-author Zoé Pochon, a doctoral student at Stockholm University.

The aptly-named messenger RNA (mRNA) "is DNA's messenger," she told Live Science in an email. "In other words, it carries working copies of DNA instructions from the nucleus to the cell." Other parts of the cell then follow these instructions, she added.

In the new study, published Friday (Nov. 14) in the journal Cell, the researchers turned to 10 well-preserved woolly mammoth (Mammuthus primigenus) specimens from Siberia that dated to 10,000 to 50,000 years. The team hoped that the frozen conditions had preserved more of the specimens and so would produce better results.

One specimen in particular — Yuka, a ginger-colored juvenile mammoth — yielded spectacular results. Yuka is about 39,000 years old, making this the oldest RNA sequenced to date. Previously, that distinction was held by tissues sampled from a canid dated to approximately 14,300 years.

Remarkably, the scientists found definite genetic signals that Yuka, previously believed to be a female based on its physical attributes, is actually a male.

Additionally, the RNA offered insights into Yuka's muscle function — specifically, the RNA "creating the proteins that are stretching and contracting the muscles," said study lead author Emilio Mármol Sánchez, who was working at the Center for Evolutionary Hologenomics, University of Copenhagen at the time of the paper. The team "also found a whole set of regulatory genes,' he told Live Science.

When cells die, what is left behind is the last function of the RNA. "What we are capturing here is, in a sense, a snapshot of the last moments of the life of these mammoths" within their cells, Mármol Sánchez said.

What the team saw in Yuka's muscle RNA reflects the potential horror of its last moments. Mármol Sánchez explained that they uncovered "molecular evidence of metabolic cell stress in Yuka's muscle," which corresponds with what a separate scientific team described in 2021. In that study, the researchers noted many claw marks that may have been made by cave lions (Panthera spelaea), as well as bite marks from smaller predators on the mammoth's body and tail. But whether Yuka was hunted and killed by large predators or simply scavenged after death is unknown. The researchers do not know what caused the cell stress observed in the RNA.

Federico Sánchez Quinto, a paleogenomicist at the National Autonomous University of Mexico's (UNAM) International Laboratory for Human Genome Research who was not involved in the research, considers this "a breakthrough publication in the field of paleogenomics." He described the study as "fascinating since it accomplishes something that had been previously unimaginable, as RNA is extremely unstable even in favorable conditions." Moreover, "this study obtains RNA from an older sample [than other recent RNA work], in larger amounts and with more certainty," he told Live Science in an email.

The findings have revealed that it's possible to extract RNA from extremely old specimens and showcases a new area of potential study for other researchers, the team said. In addition, the team has included a roadmap to help others successfully obtain ancient RNA.

"Being able to recover RNA from ancient samples, in addition to DNA, is like opening a new window into the biology of extinct animals," study co-author Love Dalén, professor of evolutionary genetics at the Centre for Palaeogenetics at Stockholm University, told Live Science. "It's yet another powerful tool that lets us see which genes were active in different cell types, which ultimately can help us better understand which genes made a mammoth a mammoth!”

Giant North American "hell pigs" may have munched on bones around 30 million years ago, while their smaller counterparts ripped through softer material, like flesh, new research finds.

The "hell pigs," scientifically known as Archaeotherium ("ancient beast" in Greek), were a group of pig-like creatures that could be as tall as humans while standing on four legs and potentially weigh more than 2,000 pounds (1,000 kilograms).

Researchers have known about Archaeotherium since 1850. But now, a new tooth analysis reveals that these beasts' feeding strategies were more varied than previously assumed. By examining tooth wear, researchers saw that larger species were crushing bones or other hard material, while smaller species were likely shearing soft foods, potentially giving them different roles on the ancient North American landscape.

"We can't assume that they were doing the same thing," Brynn Wooten, a doctoral candidate at Vanderbilt University in Tennessee, told Live Science.

Wooten presented preliminary findings from her research Thursday (Nov. 13) at the Society of Vertebrate Paleontology 2025 annual meeting. The findings haven't been peer-reviewed yet, as Wooten and her colleagues still have to complete their research and submit it to a journal.

Whale of a pig

Archaeotherium roamed across North America from about 37 million to 23 million years ago. Despite their vaguely hoggish appearance, Archaeotherium was more closely related to whales and hippos than to pigs. Their heads were around 30% of their total body length (it varied by species), but their small brains meant they weren't the brightest tools in the Paleogenic shed.

"Archaeotherium has a brain-to-body mass ratio similar to that of reptiles, so they were very unintelligent creatures," Wooten said. "Their heads were massive, but they had little tiny brain cases."

Researchers previously suggested that Archaeotherium could have been active predators, scavengers and/or vegetation strippers. Bite marks on the fossils of Poebrotherium — small camel relatives that used to roam North America — indicate that Archaeotherium may have hunted Poebrotherium and stored some of the carcasses for leftovers.

For the new research, Wooten and Larisa DeSantis, an associate professor of biological sciences at Vanderbilt University, examined a variety of Archaeotherium teeth from different states, including Nebraska, South Dakota, Oregon and Colorado. By using dental microwear texture analysis, which involves creating 3D scans of the tooth surface with a powerful microscope, they could compare wear variation between the different Archaeotherium teeth.

On the whole, Archaeotherium was typically similar to peccaries (pig-like animals found in the Americas), which shear their food. However, wear on the larger-bodied Archaeotherium was statistically indistinguishable from that of lions and hyenas and indicative of an animal that crushed its food.

"It's really interesting that the large ones are capable of crunching bones," DeSantis told Live Science. "The small ones are not."

The crushing wear could mean that the larger species engaged in more scavenging behaviors, potentially using their great size to bully other predators off their kills, the researchers suggested. On the other hand, the larger Archaeotherium could have been consuming more hard vegetarian foods, such as tubers or woody browse. The soft veggie option for smaller Archaeotherium may have been leaves and grasses.

So far, the dental analysis reveals only the texture of Archaeotherium food — not which species they ate. Wooten will now explore other research techniques, including calcium isotope analysis, to confirm whether bone was part of Archaeotherium's diet.

Researchers have unearthed a giant "warrior" lizard that stalked Brazil 240 million years ago in the Triassic period, just before the dawn of the dinosaurs. The discovery fills in gaps in our understanding of the time before the dinosaurs dominated Earth, and further highlights the links between what is now Africa and South America.

The armor-plated reptile resembles a dinosaur but is actually an ancestor of modern crocodiles. Scientists have called the creature Tainrakuasuchus bellator, which is a mixture of Greek, Latin and Indigenous Brazilian language Guarani, meaning "pointed-tooth warrior crocodile." The team revealed its findings in a study published in the Journal of Systematic Palaeontology on Nov. 13.

"Its discovery helps illuminate a key moment in the history of life, the period that preceded the rise of the dinosaurs," study lead author Rodrigo Temp Müller, a paleontologist at the Federal University of Santa Maria in Brazil, said in a statement.

During the Triassic (252 million to 201 million years ago), Archosaurs dominated the world of land-based vertebrates — the name means "ruling reptiles" — and is split into two main groups. One group, Ornithosuchia, evolved into birds and dinosaurs, while the other, Pseudosuchia, gave rise to crocodilians, such as modern crocodiles.

T. bellator belongs to Pseudosuchia. It was about 7.9 feet (2.4 meters) long and weighed 130 pounds (60 kilograms). It had a long neck and thin jaw full of sharp teeth. Very few of these types of Pseudosuchia (called poposauroids) have been found in South America, the researchers noted.

The team found the partial skeleton of T. bellator, including the lower jaw, backbone and pelvis, during an excavation in May in the Dona Francisca municipality in Brazil.

The reptile's back was covered in bony plates called osteoderms, which modern crocodiles also have.

"This animal was an active predator, but despite its relatively large size, it was far from the largest hunter of its time, with the same ecosystem home to giants as big as seven meters [23 feet] long," said Müller, who led the team of palaeontologists that excavated T. bellator. "Despite the diversity of pseudosuchians, they remain poorly understood." Fossils of some of their lineages, such as poposauroids, are "extremely rare" in the fossil record, he said.

T. bellator is closely related to another individual discovered in Tanzania, he said. Mandasuchus tanyauchen, discovered in 1933, lived about 245 million years ago, when Africa and South America were both part of the supercontinent Pangea.

"At that time, the continents were still united, which allowed the free dispersal of organisms across regions that are now separated by oceans," Müller said. "As a result, the faunas of Brazil and Africa shared several common elements, reflecting an intertwined evolutionary and ecological history."

Rock hyraxes, known in southern Africa more often as "dassies," are furry, thickset creatures with short legs and no discernible tails. They spend much of their time sunning themselves on rocky outcrops.

Another thing they sometimes do is drag their butts along the ground. Dog owners know that this behavior can be a sign of parasitic infections; in hyraxes the reason seems to be less clear, but this action leaves distinctive traces in sandy areas.

Traces and tracks — ancient, fossilized ones — are what we study at the African Centre for Coastal Palaeoscience through the Cape south coast ichnology project. Over the past few decades, we have found almost 400 vertebrate tracksites on this coast, some as old as 400,000 years, in cemented dunes known as aeolianites from the Pleistocene epoch. This epoch lasted from about 2.58 million years ago to about 11,700 years ago.

We're building up a picture of the environment during that period and how the animals and plants of that time lived.

Among our latest finds are two fossilized traces that appear to have been made by rock hyraxes long ago. One is a track site and the other is a butt-drag impression with what may be a fossilized dropping in it.

The probable track site was brought to our attention from a site near Walker Bay on the Cape south coast by an ardent tracker, Mike Fabricius. It is around 76,000 years old. We found the probable butt-drag impression east of Still Bay on the same coast, and it is most likely around 126,000 years old.

The butt-drag impression is the first fossil of its kind to be described from anywhere in the world. In addition, these are the only possible fossilized hyrax tracks ever to be identified. In the world of paleontology, anything this unusual is important and we feel privileged to be able to interpret them.

Interpreting the drag mark

Dating on our sites has been done through a technique known as optically stimulated luminescence, which works by analyzing when materials like sand were last exposed to light.

The butt-drag impression is 95 cm [37.4 inches] long and 13 cm [5.1 inches] wide. It contains five parallel striations. Its outer margins are slightly raised, and within it there is a 2 cm-high [0.8 inch] raised feature, 10 cm by 9 cm [4 by 3.5 inches]. Clearly something was dragged across the surface when it consisted of loose sand.

We considered possible causes other than hyrax buttocks. These included a leopard or an ancestral human dragging prey, or perhaps an elephant dragging its trunk. Firstly, however, these would be expected to leave tracks, and secondly in such interpretations the raised feature could not be explained.

But if it was a hyrax, it would make sense, because the buttock trace would have come after the tracks and wiped them out. And the raised feature might be a coprolite: a fused fossilized mass of hyrax droppings.

Old dung and urine

Rock hyraxes leave much more than just tracks and butt-drag traces. Because they prefer rocky areas, their tracks are not often found, but they polish rock surfaces to a shiny finish. This is similar to what buffalo on the North American prairie do, creating "buffalo rubbing stones".

Hyraxes also leave deposits of urine and dung. Urea and electrolytes are concentrated in their urine, and they excrete large amounts of calcium carbonate. This becomes cemented and forms extensive whitish deposits on rock surfaces. Due to their communal habits, hyraxes often urinate in the same preferred localities over multiple generations.

Their urine and dung often mix to form a substance known as hyraceum — a rock-like mass that can accumulate into extensive, dark, tarry deposits. Hyraceum has been used as a traditional medication to treat a variety of ailments, including epilepsy, and for gynecological purposes.

Hyraceum may be tens of thousands of years old, and can be regarded as a threatened, non-renewable resource. The middens, being sensitive to environmental changes and containing fossil pollen and other evidence of ancient life, form valuable natural archives for interpreting past climates, vegetation and ecology.

Thinking of hyraceum as a trace fossil, something which apparently has not been done before, can help in the protection of this underappreciated resource.

Although fossilized urine is globally uncommon, there is a word to describe it: "urolite", to distinguish it from "coprolite" (fossilized poop). It seems that hyraxes contribute the lion's share of the world's urolite. At paleontology conferences, students can be seen sporting T-shirts that brazenly state: "coprolite happens". In southern Africa, a more appropriate term might be "urolite happens".

Through appreciating the importance of butt-drag impressions, urolites, coprolites and hyraceum, and learning about the environment of rock hyraxes and other animals during the Pleistocene, we will never view these endearing creatures in the same light again.

This edited article is republished from The Conversation under a Creative Commons license. Read the original article.

Almost four decades ago, researchers discovered a collection of perfectly preserved fossils inside an impact crater in the Canadian High Arctic. Now, those remains have finally yielded their secrets, revealing they belong to an extinct species of hornless rhinoceros that lived 23 million years ago.

Scientists have called the animal Epiatheracerium itjilik, with the species name meaning "frost" or "frosty" in Inuktitut. These creatures were similar in size to modern Indian rhinos (Rhinoceros unicornis), according to a statement from the Canadian Museum of Nature (CMN). The newly identified fossils are the only specimen found to date and show that the animal died of unknown causes as a young adult.

"What's remarkable about the Arctic rhino is that the fossil bones are in excellent condition," Marisa Gilbert, a CMN paleobiologist and co-author of a new analysis of the remains, said in the statement. "They are three-dimensionally preserved and have only been partially replaced by minerals. About 75% of the skeleton was discovered, which is incredibly complete for a fossil."

The bones were preserved inside the 14-mile-wide (23 kilometers) impact crater thanks to it rapidly filling with water. The crater formed from an asteroid or comet around the same time that the Arctic rhino lived, which suggests the rhino died inside the crater before it became a lake.

The climate in this region was far warmer then than it is today, and plant remains show that the Canadian High Arctic — specifically, Devon Island in Nunavut, where the crater is located — hosted a temperate forest, according to the statement.

As the Miocene epoch (23 million to 5.3 million years ago) transitioned into the Pliocene epoch (5.3 million to 2.6 million years ago) and finally gave way to the last ice age, the fossils were broken up by freeze and thaw cycles and gradually pushed to the surface of the crater. Researchers then found the fossils in 1986.

Subsequent field trips to the crater uncovered more bones belonging to the Arctic rhino specimen. These expeditions also unearthed another species that lived 23 million years ago, the walking seal (Puijila darwini), which likely lived alongside Arctic rhinos.

Gilbert and her colleagues described E. itjilik based on the characteristics of its teeth, lower jawbone and cranium compared with other rhino species. The researchers then determined the Arctic rhino's place in the rhinoceros evolutionary tree by analyzing the newfound species' ties to 57 extinct and living rhino groups. They published their results Tuesday (Oct. 28) in the journal Nature Ecology and Evolution.

The findings suggest E. itjilik was most closely related to rhinos that lived in what is now Europe earlier than 23 million years ago. True modern rhinos (Rhinocerotidae) evolved about 40 million years ago in North America and Southeast Asia, and their descendants subsequently spread to every continent except South America and Antarctica.

"Today there are only five species of rhinos in Africa and Asia, but in the past they were found in Europe and North America, with more than 50 species known from the fossil record," study lead author Danielle Fraser, a research scientist and head of paleobiology at CMN, said in the statement.

The newfound Arctic rhino is the most northerly rhinoceros ever discovered. The researchers think the species migrated from Europe via the North Atlantic Land Bridge, an ancient passage over Greenland consisting of exposed continental crust.

The North Atlantic Land Bridge emerged in the latter stages of the Cretaceous period (145 million to 66 million years ago), but when it disappeared is debated. Some studies indicate that the land bridge collapsed 56 million years ago; others suggest the bridge was more or less continuous until about 2.7 million years ago.

The new findings lend support to the latter hypothesis, because Rhinocerotidae arrived in Europe 33.9 million years ago, during an extinction and dispersal event known as the Grande Coupure, or "great cut." The new study suggests that by 23 million years ago, these rhinos had arrived in North America, so the land bridge likely persisted at least until the beginning of the Miocene epoch.

"It's always exciting and informative to describe a new species," Fraser said. "Our reconstructions of rhino evolution show that the North Atlantic played a much more important role in their evolution than previously thought."

A pivotal new dinosaur study is finally settling a fierce, four-decade-long debate: Was the small tyrannosaur Nanotyrannus a distinct species or merely a teenage Tyrannosaurus rex? Now, a remarkably complete fossil reveals that Nanotyrannus was real.

For years, key fossils were thought by many paleontologists to be juvenile examples of Tyrannosaurus rex, which lived between 67 million and 66 million years ago in western North America. Rather than settling all arguments, however, this "nano" discovery opens a new chapter in understanding T. rex biology and further debate.

A key source of the argument has been a small 67 million-year-old tyrannosaur skull found in the Hell Creek Formation of Montana in 1942. It was given its own species name Nanotyrannus lancensis, in 1988, meaning that the species was based on a single skull, and no one knew what the rest of its body looked like.

"This has been one of the most controversial topics in all of dinosaur paleontology," study co-author Lindsay Zanno, a paleontologist at North Carolina State University and North Carolina Museum of Natural Sciences, told Live Science.

Apart from the isolated skull, the best skeleton of one of these small-body tyrannosaurs came from the Hell Creek Formation, which also spans parts of North Dakota, South Dakota and Wyoming. This specimen, known as Jane, was still rapidly growing and aged about 11 when it died, and differed in several ways from the lone skull.

Now, Zanno and study co-author James Napoli, an anatomist at Stony Brook University in New York, have described a complete tyrannosaur skeleton that is part of the "Dueling Dinosaurs" fossils, the 67 million-year-old remains of what seemed to be the most complete, yet small, T. rex on record and a Triceratops, possibly locked in combat when they died.

The case for Nanotyrannus

Zanno and Napoli say this "Dueling Dinosaurs" skeleton of a tyrannosaur, also from the Hell Creek Formation, isn't a T.  rex and instead shares features with the N. lancensis skull. Crucially, their analysis of growth rings in the bones, spinal fusion data and developmental anatomy indicates that the fearsome dinosaur was about 20 years old and almost fully grown when it died, rather than being a juvenile.

"We were able to take a thin section of the limb bones of this animal and determine that it was in fact, nearly a full-grown individual even though it was only half the length and about 1/10th of the mass of a full, grown T. rex," Zanno said.

It would have weighed just 1,500 pounds (700 kilograms), whereas an adult T. rex would have weighed in at more like 14,700 to 18,000 pounds (6,700 to 8,200  kg). It also has larger forelimbs, more teeth, fewer tail vertebrae and distinct skull nerve patterns. The researchers reported the research on Thursday (Oct. 30) in the journal Nature.

The two dinosaurs would have had very different ecologies, Zanno said. T. rex was a bulky predator with a massive skull, powerful bite force and serrated teeth the shape of bananas. Nanotyrannus was small and slender, swifter and more agile, with enlarged hands and claws, which it would have used for prey capture, she said.

Paleontologists respond

The wider research community seems convinced by this new evidence that this small dinosaur and T. rex are different species.

"Fundamentally and on balance, it looks pretty solid," Dave Hone, a paleontologist at Queen Mary University of London, told Live Science. "I and many other people who have said we don't think Nanotyrannus is valid have always said that the main reason for this is we just don't have any apparent adult small skeletons and that's obviously a pretty big deal. And this really, really looks like an adult small skeleton."

Steve Brusatte, a paleontologist at the University of Edinburgh in Scotland, thinks similarly. "For many years in my research on tyrannosaurs, I've considered a set of smaller skeletons found in the same rocks as the famous skeletons of huge T. rexes to be juveniles of T. rex rather than a distinctive smaller species," he told Live Science in an email. "Evidence from this exquisite new specimen shows that I was wrong — at least in part. The case for Nanotyrannus, a species of long-armed tyrannosaur smaller than T. rex, looks strong, and I think proven beyond a reasonable doubt now."

Thomas Carr, a paleontologist at Carthage College in Wisconsin who has previously argued that all the fossils are juvenile T. rex, has also changed his mind on that front. "I think they've shown decisively that the dueler is a small adult tyrannosaur, so I don't have a problem with that at all," he told Live Science.

However, Carr disagrees with the family tree that Zanno and Napoli suggest, which has Nanotyrannus as a more primitive group outside the Tyrannosauridae family. He said the specimen should be considered a sister species of T. rex, and should be renamed as Tyrannosaurus lancensis.

Is Jane a new species?

Other parts of Zanno and Napoli's paper are more controversial. They examined more than 200 other tyrannosaur fossils, and say that the Jane skeleton differs both from T. rex and the dueling N. lancensis. Jane would have been slightly larger than the dueler, and has a unique sinus pattern in the palate and a differently shaped bone behind the eye.

This leads them to suggest that Jane represents a new species, Nanotyrannus lethaeus — named for the River Lethe from Greek mythology — although they haven't yet described it fully.

"They may have been separated in time or they may have been overlapping and that's something we are not sure of yet," Zanno said.

Barring further finds that shed more light on Jane's anatomical features, the distinctions here are sufficient to justify two species, Thomas Holtz, a palaeontologist at the University of Maryland, told Live Science in an email.

But many researchers remain unconvinced regarding Jane being a new species. "This second described species of Nanotyrannus is based on a small skeleton that clearly had not stopped growing, so I think it's frankly very hard to tell if this was a Nanotyrannus or a juvenile T. rex," Brusatte said.

"I have a different way of looking at the evidence and that is that Jane is a juvenile T. rex," said Carr, who has studied Jane extensively.

The new study suggests that more than one tyrannosaur species shared the same western North American ecosystem in the final million years before the asteroid impact some 66 million years ago, Zanno said.

"I certainly don't have any a priori problem that there's more than one species of carnivore out there at the same time," Hone said. "It was very weird that there were no others."

But if most of the smaller tyrannosaurs at Hell Creek are species other than T. rex, as Zanno and Napoli suggest, that means there is a lack of analyzed juvenile skeletons that are definitely of T. rex.

"Tyrannosauruses were running around for several million years," Hone said. "They're massive, we found loads of adults and they don't just pop into existence at 10 meters [33 feet] long and 5 tonnes [5.5 tons]. So, where, where are the juveniles?"

This lack of juvenile specimens also means we have to re-evaluate ideas of how T.  rex grew — the previous idea was that the species changed quite dramatically as it reached maturity. "We have to rethink a lot of what we know about T. rex life history, growth, paleobiology, because Nanotyrannus has been used as data to understand T. rex and its biology for decades," Zanno said.

She, Hone and Carr suggest that models of T. rex growth should be based on the development of one of its closest relatives, a dinosaur called Tarbosaurus bataar from Mongolia, for which many skeletons ranging from baby to adult exist. Tarbosaurus young look like scaled-down adults rather than having bigger skeletal differences.

"The overarching mic drop of this paper is that Nanotyrannus is real, its own distinct tyrannosaur species, and that necessitates a fundamental reassessment of tyrannosaur classification and evolution," Brusatte said.

Two extremely rare dinosaur "mummies" found in the badlands of Wyoming are the first examples of hoofed reptiles, according to a new study.

Researchers discovered the pair of 66 million-year-old duck-billed dinosaur (Edmontosaurus annectens) skeletons complete with skin, spikes and hooves, as if the creatures had been naturally mummified.

The fossils aren't true mummies, as their original tissues have been replaced with rock, but they give scientists an unprecedented look at duck-billed dinosaur biology, confirming they had hooves. The researchers reported their findings Oct. 23 in the journal Science.

"It's the first time we’ve had a complete, fleshed-out view of a large dinosaur that we can really feel confident about," study senior author Paul Sereno, a professor of organismal biology and anatomy at the University of Chicago, said in a statement.

Duck-billed dinosaurs used their hooves to stomp through mud at the end of the Cretaceous period (145 million to 66 million years ago). They lived alongside other large dinosaurs, such as Tyrannosaurus rex and Triceratops, just before the age of dinosaurs came to a crashing end when a massive asteroid hit Earth and wiped them all out (except for birds).

Dinosaur mummies are exceptionally preserved fossils that contain a clay copy of dinosaur skin and other organic tissues. Several of these fossils were discovered in Wyoming in the early 1900s, which inspired the new research. Sereno and his colleagues found the two new specimens by tracking down the locations of the historical discoveries, using old photographs and letters, and mapping out what they described as a "mummy zone."

One of the newly discovered Edmontosaurus specimens, nicknamed "Ed Jr.," was a late juvenile and estimated to be about 2 years old at the time of its death. The other specimen, nicknamed "Ed Sr.," was an early adult about 5 to 8 years old when it perished.

The researchers reconstructed the dinosaurs' biology, movement and preservation using a variety of imaging techniques, including X-rays and micro-CT scans, as well as by analyzing clay, examining the site where they were discovered, and studying fossilized duck-billed dinosaur footprints.

The dinosaurs had a fleshy crest running along their neck and trunk that transitioned into a row of spikes at the tail. Small, pebble-like scales also peppered the animal's lower body and tail, the largest of which were only 0.2 inches (4 millimeters) across — tiny considering the dinosaur could grow to more than 40 feet (12 meters) long, according to the statement.

The team determined that the mummification-like preservation occurred because the dinosaurs' bodies were dried out in the sun — they may well have perished in a drought — before being quickly covered in a flash flood. Static electricity, reacting with microorganisms on the surface of the carcasses, then sucked clay from the wet sediment to form a thin template later around the remains. The organic material then slowly decayed and was replaced with rock.

"There are so many amazing 'firsts' preserved in these duck-billed mummies — the earliest hooves documented in a land vertebrate, the first confirmed hooved reptile, and the first hooved four-legged animal with different forelimb and hindlimb posture," Sereno said.

Some of the last dinosaurs in the world were healthy and thriving right up until the day they were annihilated by asteroid Armageddon, a new study on fossils from New Mexico finds.

Scientists have debated for decades whether non-avian dinosaurs were in decline before a massive asteroid struck Mexico's Yucatán Peninsula at the end of the Cretaceous period (145 million to 66 million years ago). The new study, published Thursday (Oct. 23) in the journal Science, supports previous evidence that the dinosaurs were struck down in their prime and might have still roamed Earth if it weren't for that pesky asteroid.

Researchers dated rocks from the Naashoibito Member fossil site in New Mexico, which preserved a rich Cretaceous ecosystem home to a variety of dinosaurs, including the 70-foot-long (21 meters) long-necked sauropod known as Alamosaurus, as well as meat-eating tyrannosaurs, horned dinosaurs and duck-billed dinosaurs. The dating revealed that this ecosystem existed just before the Chicxulub asteroid strike, suggesting that New Mexico's last dinosaurs were doing well before the giant space rock brought death from the sky.

"At least before the mass extinction event, they appear to be thriving," study lead author Andrew Flynn, an assistant professor in the Department of Geological Sciences at New Mexico State University, told Live Science in an email. "There is a diverse dinosaur fauna in the Nasshoibito Member in New Mexico so the dinosaur population appears to be healthy."

The asteroid triggered a mass extinction event in which around 75% of living species went extinct, including all dinosaurs, except for birds. Previously, some research has suggested that dinosaur diversity declined as part of a restructuring in the Maastrichtian age (72.1 million to 66 million years ago) of the Cretaceous, with environmental factors such as climate change making the dinosaurs more vulnerable to catastrophe. However, other researchers have argued that the asteroid interrupted an age of prosperity for the dinosaurs.

Much of what scientists know about the Cretaceous-Paleogene (K-Pg) boundary — the rocks that mark the end of the Cretaceous period — has come from formations such as Hell Creek and Fort Union in the northern Great Plains U.S., which means there's a lot of uncertainty surrounding what was happening elsewhere.

Paleontologists knew that the Naashoibito Member featured New Mexico's last known non-avian dinosaurs, but the precise age of these fossils has been up for debate. In the new study, researchers sought to resolve this uncertainty by combining two rock dating methods.

"We wanted to get two different, independent ways of determining the age of the rocks," Flynn said.

The first of these methods involved measuring radioactive decay in argon isotopes. The second took advantage of magnetic fields: Earth's magnetic field flips between a "normal" state, when magnetic north is north (how it is today), and a reversed state, when magnetic north is south. Researchers know when these flips have occurred through Earth's history, so by measuring magnetic pole direction in rocks, they can deduce their age.

The dating methods placed the Naashoibito Member between about 66.4 million and 66 million years ago — meaning that the dinosaurs there lived within about 340,000 years of the asteroid strike. The researchers also found that New Mexico's dinosaurs were unique, suggesting that western North America had distinct pockets of dinosaur diversity.

"These revised estimates of dinosaur diversity during the Maastrichtian still do not match the bounty of the preceding Campanian Age — the apparent zenith of dinosaur diversification in North America," Lindsay Zanno, a paleontologist at North Carolina State University who was not involved in the study wrote in an accompanying perspective published in Science. "Nonetheless, current estimates of Maastrichtian biodiversity are still higher than those for most other Late Cretaceous ages."

The new study paints a picture of dinosaurs suffering an abrupt extinction with the asteroid strike, leading to the rapid rise of mammals soon after. However, it's still unclear whether this was the case everywhere.

"This work really highlights the need to work on new, previously understudied localities across this incredibly important time in Earth's history," Flynn said. "Just adding one new, well dated dinosaur bearing locality in western North America allows us to see this really interesting picture of dinosaurs."

A nearly complete fossil skeleton found on the U.K.'s Jurassic Coast represents a newly identified species of ancient marine reptile that lived alongside dinosaurs.

The ichthyosaur, dubbed Xiphodracon goldencapsis, was likely around 10 feet (3 meters) long when it lived, according to a study published Friday (Oct. 10) in the journal Papers in Palaeontology. It had large eye sockets and a long, narrow snout shaped like a sword.

The specimen dates to a period in the Early Jurassic known as the Pliensbachian, which lasted from about 193 million to 184 million years ago. By studying an ichthyosaur fossil from this period, scientists could learn more about a critical point in these aquatic animals' evolution, according to the study.

Fossil collector Chris Moore found the remains in 2001 along the Jurassic Coast, a 96-mile (154 kilometers) stretch of seaboard in Dorset known for being a treasure trove of fossils.

Moore sold the fossil to the Royal Ontario Museum in Canada shortly thereafter. Although it was identified as an ichthyosaur, it wasn't studied in detail until recently.

"I remember seeing the skeleton for the first time in 2016," study co-author Dean Lomax, a paleontologist at the University of Manchester and the University of Bristol, said in a statement. "Back then, I knew it was unusual, but I did not expect it to play such a pivotal role in helping to fill a gap in our understanding of a complex faunal turnover during the Pliensbachian."

The new genus name, Xiphodracon, comes from the Greek words "xiphos," meaning sword, and "dracon," meaning dragon — a reference to ichthyosaurs' "sea dragons" nickname. Its species name, "goldencapsis," comes from Golden Cap, the site on the Jurassic Coast where the ichthyosaur was found.

The fossil also hints at how the individual ichthyosaur lived and died.

"The limb bones and teeth are malformed in such a way that points to serious injury or disease while the animal was still alive, and the skull appears to have been bitten by a large predator — likely another much larger species of ichthyosaur — giving us a cause of death for this individual," study co-author Erin Maxwell, curator of fossil aquatic vertebrates at the State Museum of Natural History Stuttgart in Germany, said in the statement. "Life in the Mesozoic oceans was a dangerous prospect."

X. goldencapsis could also help to clarify a major shift in ichthyosaur speciation in the early Jurassic. Although scientists have found many ichthyosaur fossils from before and after the Pliensbachian, the two groups have very few species in common, suggesting a major turnover sometime during the Pliensbachian. In fact, ichthyosaur fossils from the Pliensbachian period are rare.

The newly discovered ichthyosaur "is more closely related to species in the later Early Jurassic … and its discovery helps pinpoint when the faunal turnover occurred, being much earlier than expected," Lomax said. In other words, the shift likely occurred in the early Pliensbachian. However, scientists don't yet know what caused this upheaval.

For now, the X. goldencapsis fossil will be displayed at the Royal Ontario Museum.

The fossilized skeleton of a Jurassic reptile that appears to be part lizard, part snake, has been unearthed on Scotland's Isle of Skye.

This mysterious lizard had hooked, snake-like teeth for hunting down prey 167 million years ago, a new study has found.

The newly discovered species is named Breugnathair elgolensis, which means "false snake of Elgol," honoring the creature's confusing anatomy and the Elgol area of southern Skye, where the fossil was found, according to the study published Wednesday (Oct.1) in the journal Nature.

B. elgolensis was only about 16 inches (41 centimeters) long, but that still made it one of the largest lizards in its ecosystem, according to a statement released by the researchers. Scientists suspect that it hunted smaller lizards, early mammals and even young dinosaurs, such as small herbivorous heterodontosaurids and predatory bird-like paravians.

It had a snake-like jaw and curved teeth similar to a modern python, but its body was short, with fully formed limbs like a lizard. B. elgolensis also had gecko-like features on some of its bones, including the back of its skull. Researchers are still deciphering B. elgolensis' evolutionary history, but its discovery could change the way they look at early snake evolution.

Related: Night lizards survived dinosaur-killing asteroid strike, despite being close enough to see it happen

Scientists currently have a scattered understanding of early lizard and snake evolution. Both animals belong to a group called Squamata, which emerged about 190 million years ago. There's some overlap between members of the group, but lizards came first and generally have four limbs, while snakes are limbless.

"The Jurassic fossil deposits on the Isle of Skye are of world importance for our understanding of the early evolution of many living groups, including lizards, which were beginning their diversification at around this time," study co-lead author Susan Evans, a professor of vertebrate morphology and paleontology at the University College London, said in the statement.

Study co-author Stig Walsh, a senior curator of vertebrate paleobiology at the National Museums Scotland, first uncovered the B. elgolensis fossil in 2015. The team has since spent nearly a decade preparing and studying the specimen, which has included subjecting it to high-powered X-rays and detailed computed tomography (CT) imaging scans.

The researchers determined that B. elgolensis belonged to a Squamata sub-group called Parviraptoridae, which was previously only known from fragments of other fossils. While snake-like bones had been found in close proximity to gecko-like bones, some scientists had assumed they came from two separate animals. The new fossil confirms that one species did indeed have both features, according to the statement.

"I first described parviraptorids some 30 years ago based on more fragmentary material, so it's a bit like finding the top of the jigsaw box many years after you puzzled out the original picture from a handful of pieces," Evans said. "The mosaic of primitive and specialized features we find in parviraptorids, as demonstrated by this new specimen, is an important reminder that evolutionary paths can be unpredictable."

The researchers still aren't sure whether snakes evolved from species like B. elgolensis or whether snakes independently evolved similar mouth parts. It's also possible that B. elgolensis is a stem lineage within Squamata, helping to give rise to all lizards and snakes.

"This fossil gets us quite far, but it doesn't get us all of the way," study lead author Roger Benson, the Macaulay Curator at the American Museum of Natural History's Division of Paleontology, said in the statement. "However, it makes us even more excited about the possibility of figuring out where snakes come from."

Around 95 million years ago, small crocodile-like creatures with strange, sheathed teeth burrowed along the shores of the Western Interior Seaway in what is now southwest Montana, a new study suggests.

The new research describes the first such creature ever discovered — a teenage croc nicknamed Elton that measured about 2 feet (60 centimeters) long from nose to tail tip. Elton's fossilized remains were discovered in 2021 during an organized dig in the Blackleaf geological formation, which dates to the middle of the Cretaceous period (145 million to 66 million years ago).

"We have found dinosaurs (in the Blackleaf) before, but this was the second known vertebrate animal we'd ever found in this formation," lead author Harrison Allen, a doctoral student in paleontology at Stony Brook University in New York, who found the fossil when he was an undergraduate student at Montana State University, said in statement. "It led me down the rabbit hole into this amazing world of prehistoric, extinct crocs and their evolutionary niches."

The first fossil Allen noticed was Elton's skull, which was just 2 inches (5 cm) long and embedded in rock, according to the statement. Allen showed the miniature skull to David Varricchio, a professor of paleobiology, taphonomy and ichnology at Montana State University, who immediately understood the fossil's significance.

"After the dig, Dr. Varricchio told me why he was so excited the day I found the initial specimen," Allen said. "It has so much visible anatomy to explore, and he could see it was a tiny, tiny croc skull, fully articulated and preserved — it was a special thing."

It turns out, Elton belonged to a now-extinct family of crocodile-like creatures, or crocodyliforms, that researchers previously didn't know existed. This family, called Wannchampsidae, sits within the lineage Neosuchia, which includes all modern crocodilians and their closest extinct relatives. Its members lived in North America during the Cretaceous, and they were much smaller than other neosuchian crocs are; had Elton survived until adulthood, he would have grown to just 3 feet (90 cm) long, according to the statement.

Neosuchians are typically semi-aquatic or marine carnivores with simple, conical teeth — but not Elton. He and fellow members of the newfound species, named Thikarisuchus xenodentes, had an assortment of differently shaped teeth, including sheathed and other specialized fangs, which they used to devour plants and insects, according to the statement.

Elton and his kind also lived on land, and they likely made burrows in the ground, based on how densely packed Elton's bones were when Allen and his colleagues analyzed them, the statement said.

Shortly after finding Elton's skull, Allen returned to collect bagfuls of the surrounding sediment to search it for more clues about the animal. He spent hours sifting through the dirt, extracting fragments of bone and reconstructing the Thikarisuchus skeleton bit by bit. He worked with his classmate Dane Johnson, now a paleontology lab and field specialist at the Museum of the Rockies in Montana — often to the tune of Elton John's 1972 song "Crocodile Rock," which inspired the name Elton.

To get a clear picture of the fossils, Allen then made CT scans, which helped him distinguish between the bones and chunks of rock that were still stuck to Elton's remains. "Harrison worked super hard to digitally reconstruct the animal, and it came out beautifully," Varricchio, who is a co-author of the new study, said in the statement.

A detailed description and pictures of T. xenodentes, as well as a discussion of the newfound species' position in the evolutionary tree, are included in the study, published Sept. 22 in the Journal of Vertebrate Paleontology. Notably, the researchers highlight a family of ancient crocodyliforms called Atopasauridae that was previously found in Eurasia and looks like Elton, with a small body size and similar dental features.

"It suggests that during the same time period, we're seeing convergent evolution between two distantly related groups due to similar environmental conditions, prey availability and who-knows-what that prompted crocs on opposite sides of the planet to develop similar features," Allen said.

There is a new dinosaur king of South America. This newly discovered top predator, named Joaquinraptor casali, was some 23 feet (7 metres) long and was a fast-moving hunter with powerful "claws like hedge trimmers."

And the massive beast's remains were found with the leg bone of an ancient crocodile relative locked in its jaws.

Lead author Lucio Ibiricu, a paleontologist at CONICET's Patagonian Institute of Geology and Paleontology in Chubut, Argentina, and his colleagues unearthed the well-preserved fossil — including much of the skull, ribs, vertebrae and fore and hind-limbs — from the Lago Colhué Huapi Formation of south-central Chubut Province in central Patagonia, Argentina.

J. casali was a type of theropod dinosaur known as a megaraptor, or "large thief," that lived in the final stages of the Cretaceous period between about 70 million and 66 million years ago, before the Chicxulub asteroid slammed into the Yucatán Peninsula causing the Cretaceous–Paleogene extinction event that spelled the end for dinosaurs (except for some birds).

The megaraptors, which lived across South America, Asia and Australia, were carnivores with elongated skulls, powerful arms and big claws.

Related: Oldest-known dome-headed dinosaur discovered sticking out of a cliff in Mongolia's Gobi Desert

"Joaquinraptor provides a clearer understanding of how this enigmatic group of predatory dinosaurs lived and evolved," Darla Zelenitsky, a paleontologist at the University of Calgary in Canada who wasn't involved in the work, told Live Science. "Deemed the latest surviving megaraptoran, this fossil provides insight into the final phase of their evolutionary history in South America prior to the mass extinction."

The discovery reveals that megaraptorans (any dinosaur belonging to the Megaraptora clade, which includes megaraptors) stayed relatively large until the end of the Cretaceous, likely filling the apex predator niche in the region of southern Patagonia at that time, she said.

The lands where Joaquinraptor roamed were very different from the cool, dry Patagonian climate of today, though. Sediment from the same layer as the fossil find reveals that it was probably a warm, humid floodplain near the sea.

Ibiricu told Live Science that the first hints of the fossil were uncovered in 2019, but it took three field seasons to fully unearth it. When they finally excavated the fossil, the researchers discovered the leg bone of a crocodile relative in Joaquinraptor's jaws, hinting at its diet and that it was likely the top predator in the area.

The researchers then analyzed the histology, or microstructure, of a tibia and rib bone to work out how old the specimen was when it died.

"We know based on histology that this was a sexually mature individual but it might have been able to grow a little bit more. We know that when it died, it was at least 19 years old," Ibiricu said.

Bone measurements also led the researchers to estimate that Joaquinraptor would have been about 23 feet long and weighed more than 2,200 pounds (1,000 kilograms). The find is described in a paper published Tuesday (Sept. 23) in the journal Nature Communications.

"This is a fantastic discovery and one of the most intriguing new dinosaur discoveries in recent memory," Steve Brusatte, a paleontologist at the University of Edinburgh, Scotland who wasn't involved in the study, told Live Science. "It was dinosaurs like these that topped the southern food chain at the same time that Tyrannosaurus rex was reigning supreme in North America."

Brusatte said the two predators were drastically different, though. "Joaquinraptor was slender and svelte and fast, and it had ridiculously oversized arms and claws, like hedge trimmers. Its arms and hands make T. rex look puny by comparison, Arnold Schwarzenegger vs Danny DeVito, at least in the arms category," he said.

These differences would have meant the two apex predators would have hunted very distinctly, Zelenitsky said. "At more than four times the weight of Joaquinraptor, T. rex was a brute force predator — massive, with a bone-crushing bite. But Joaquinraptor was swift, slender and attacked with surgical precision. It would have delivered slashing bites and had long arms with big claws for grabbing, slashing and manipulating prey," she said.

Paleontologists have uncovered the oldest and most complete dome-headed dinosaur fossils to date in Mongolia's Gobi Desert.

The fossils, which are between 108 million and 115 million years old, push back the timeline for the emergence of dome-head dinosaurs, or pachycephalosaurs, by about 15 million years. The new fossils could also reveal details about the evolution and development of these dinosaurs' bizarre rounded skulls.

"Pachycephalosaurs are iconic dinosaurs, but they're also rare and mysterious," study co-author Lindsay Zanno, a paleontologist at North Carolina State University, said in a statement. These dinos thrived during the Late Cretaceous period (between 86 million and 66 million years ago).

Some scientists think the thick skulls of pachycephalosaurs helped them attract mates and fend off competition, while others suggest that these weirdos didn't butt heads, but instead kick-boxed like kangaroos. But how their rounded skulls developed is a mystery. Most known pachycephalosaur fossils are incomplete, and scientists haven't found many fossils from early in their development.

Now, in a new study, published Wednesday (Sept. 17) in the journal Nature, a group of paleontologists report a fossil that might hold some answers. In eastern Mongolia, the team found the fossilized remains of a dome-headed dinosaur from the Early Cretaceous period (145 million to 100 million years ago). They named the newly discovered species Zavacephalae rinpoche.

Zavacephalae comes from the Tibetan word "zava," meaning root or origin, and the Latin word "cephal," meaning head. "Rinpoche" is a Tibetan word meaning "precious one," so named because the team found the skull sticking out of a cliff like a polished jewel.

The fossil included about 54% of the dinosaur's bones, including the skull and entire tail, as well as several hand and leg bones and stomach stones that helped Z. rinpoche grind its food. In life, the dinosaur likely measured about 3.3 feet (1 meter) long and weighed about 12.9 pounds (5.85 kilograms).

"We age dinosaurs by looking at growth rings in bones, but most pachycephalosaur skeletons are just isolated, fragmentary skulls," Zanno said. "Z. rinpoche is a spectacular find because it has limbs and a complete skull, allowing us to couple growth stage and dome development for the first time."

Z. rinpoche's dome was fully developed, but growth rings in its lower leg bone suggest that the animal was a juvenile and was still growing when it died. Because pachycephalosaurs probably used their domes to attract mates, this suggests that the dinosaur reached sexual maturity before it was fully grown.

"If you need to headbutt yourself into a relationship, it's a good idea to start rehearsing early," Zanno said.

"This specimen is a once-in-a-lifetime discovery," Zanno added. "Z. rinpoche gives us an unprecedented glimpse into the anatomy and biology of pachycephalosaurs."

A stunning fossil find has revealed two baby pterosaurs that were struck down mid-flight in a "catastrophic" tropical storm 150 million years ago.

Researchers carried out an animal post-mortem (necropsy) on two Jurassic pterosaur skeletons from Germany and concluded that violent winds likely drove the flying reptiles into a lagoon, where they drowned under the stormy waves.

Pterosaurs, informally called "pterodactyls," ruled the skies during the age of dinosaurs. The fossilized skeletons documented in the new study belonged to the first pterosaur species ever discovered, Pterodactylus antiquus, which spawned the pterodactyl nickname.

The newborns are two of the smallest P. antiquus specimens ever discovered, with a wingspan of about 8 inches (20 centimeters) — around the size of a small bat. The researchers' analysis of these fossils, published Sept. 5 in the journal Current Biology, suggests that they were probably two of many baby pterosaurs that died in storm-related mass mortality events in the region. Adult P. antiquus had an estimated wingspan of around 3.5 feet (1.1 meters), meaning it likely had a better shot at resisting the winds that doomed the youngsters.

The baby pterosaurs are nicknamed "Lucky" and "Lucky II," according to a statement released by the researchers. While they may have been unlucky to perish in a storm, scientists were lucky that their dainty and delicate skeletons were discovered.

"Pterosaurs had incredibly lightweight skeletons," study lead author Rab Smyth, who conducted the research as part of his doctoral studies at the University of Leicester in the U.K., said in the statement. "Hollow, thin-walled bones are ideal for flight but terrible for fossilisation. The odds of preserving one are already slim and finding a fossil that tells you how the animal died is even rarer."

Related: 'Ash-winged dawn goddess' is oldest pterosaur ever discovered in North America — and it was small enough to sit 'on your shoulder'

The pterosaurs were preserved in the Upper Jurassic Solnhofen platy limestone rock formation, which is about 153 million to 148 million years old and located in Bavaria, southern Germany. Paleontologists have found hundreds of pterosaurs in this formation, which was once a semi-tropical seascape with coral reefs and small islands, according to the study.

Solnhofen's fossils are often well-preserved young pterosaurs, while larger adults are rarer and typically fragmented. This is unusual, given that larger and more robust bones often have a better chance of sticking around in an environment and becoming fossils.

Study co-author David Unwin, a palaeontologist at the University of Leicester, said that the team was very excited when Smyth came across Lucky in the Bergér Museum in Harthof but thought it was a one-off. Then, a year later, Smyth came across Lucky II — currently on display in the Burgermeister Müller in Solnhofen, but owned by the Bavarian State Collection for Palaeontology and Geology in Munich. The researchers examined the fossil with a fluorescent UV torch and saw Lucky II had suffered a telling fracture on its arm (part of its wing) before death.

"It literally leapt out of the rock at us — and our hearts stopped," Unwin said in the statement. "Neither of us will ever forget that moment."

Both Lucky and Lucky II had humeral fractures consistent with excessive wind force during flight, similar to those experienced by birds and bats during severe storms today. The researchers believe that violent gusts of wind swept the young pterosaurs away from the safety of land and forced them into the lagoon. Storm-fueled currents then quickly forced them down into the depths of the water column and buried their bodies in sediment, according to the study.

By studying the two baby pterosaurs, alongside data collected from more than 40 other Pterodactylus individuals, the team concluded that Solnhofen has so many small pterosaurs because of catastrophic mass mortality events like these storms that larger individuals would have been able to resist.

"For centuries, scientists believed that the Solnhofen lagoon ecosystems were dominated by small pterosaurs," Smyth said. "But we now know this view is deeply biased. Many of these pterosaurs weren't native to the lagoon at all. Most are inexperienced juveniles that were likely living on nearby islands that were unfortunately caught up in powerful storms."

For the first time in tropical latitudes, scientists have sequenced ancient DNA from the only mammoth endemic to North and Central America: the Columbian mammoth. The research revealed unexpected — and as yet unexplained — genetic differences that made these animals distinct from their northern counterparts.

Columbian mammoths (Mammuthus columbi) were approximately 13 feet (4 meters) tall and towered over their woolly mammoth (Mammuthus primigenius) relatives, with whom they co-existed and even interbred. Their fossils have been discovered in Canada, the U.S., Mexico and Central America. But information regarding how they evolved in the Americas remains unclear.

Construction beginning in 2019 of the Felipe Ángeles International Airport in Santa Lucía, Mexico, uncovered a vast wealth of Pleistocene (2.6 million to 11,700 years ago) fossils, including more than 100 Columbian mammoths.

The sheer amount of fossils, said Federico Sánchez-Quinto, a paleogenomicist at the National Autonomous University of Mexico's (UNAM) International Laboratory for Human Genome Research, prompted him to reach out to those involved with the excavation. This is what ultimately led to the team’s DNA work.

When an animal dies, its DNA rapidly degrades, something that is compounded further by heat. In that respect, "DNA is like ice cream," Sánchez-Quinto told Live Science, as it preserves better in the cold. Nonetheless, Ángeles Tavares-Guzmán, co-author and biotechnology engineer, was "hopeful" about their chances, especially as another team recently extracted ancient DNA from a similarly warm climate.

Related: 'Closer than people think': Woolly mammoth 'de-extinction' is nearing reality — and we have no idea what happens next

In total, the scientists sequenced 61 mitochondrial genomes from 83 mammoth molars. Five radiocarbon-dated samples indicate they were between 13,000 to 16,000 years old. The research was published Aug. 28 in the journal Science.

By piecing together ancient DNA, scientists can better trace the path mammoths took across the Americas. But in this case, the sequencing revealed some puzzling findings.

Research from 2021 indicates that a previously unknown lineage of the Eurasian steppe mammoth (Mammuthus trogontherii) mated with woolly mammoths (Mammuthus primigenius) before crossing Beringia — an icy land bridge — into North America 800,000 to 400,000 years ago, which ultimately resulted in the Columbian mammoth species.

One theory is that Columbian mammoths continued to migrate southward until eventually reaching what is now Mexico — a theory that would be substantiated by finding animals with similar DNA in both Mexico and farther north.

But instead, the team uncovered evidence that the Columbian mammoths in Mexico are genetically different from those in the U.S. and Canada. In other words, although the Mexican Columbian mammoths are the same species as U.S. and Canadian Columbian mammoths, their specific genetic make-up is different.

The team also found that the common ancestor of the Mexican Columbian mammoths diverged much earlier than those that migrated to and remained within the U.S. and Canada.

Study co-author Eduardo Arrieta-Donato, a researcher at UNAM's International Laboratory for Human Genome Research, suggested thinking of that common ancestor as the Mexican mammoths' great, great, great grandmother. "[She] was already a hybrid of the steppe mammoths and the woolly mammoths from Beringia," he said. As her descendants bred and migrated southward, they may have been isolated from other North American mammoths, which could explain that genetic uniqueness, Arrieta-Donato added.

That uniqueness suggests that Columbian mammoth evolution "was way more complicated than we thought," Sánchez-Quinto said, "and that Mexico bears important genetic variation that is not present in other places."

Interestingly, other Pleistocene species excavated in Mexico also display divergent genetic lineages compared with their northern relatives. For example, genetic variation has also been seen in Pleistocene black bears (Ursus americanus) and in at least one mastodon — an extinct type of elephant-like mammoth relative. One species with genetic variation separating them from their northern counterparts is surprising; three species showing similar genetic distinctions indicates something extraordinary happened as species migrated southward.

The new research "raises several new and very interesting questions," said Love Dalén, a professor of evolutionary genetics at the Centre for Palaeogenetics at Stockholm University who was not involved in the study.

"I am very impressed that Federico and colleagues have managed to get DNA from such heavily degraded samples!” he told Live Science in an email. "It is a mammoth feat to get DNA from tropical Late Pleistocene samples!"

Tavares-Guzmán, Arrieta-Donato and Sánchez-Quinto noted two significant aspects of their paper. First, that successfully extracting ancient DNA in Mexico challenges the expectation that DNA is less likely to be extracted in warm climates. And second, that their work shows that DNA analysis doesn’t need to be exported to other countries. "Labs in the Global South have all the capacity to carry out these projects," Sánchez-Quinto said. "Sometimes what we are missing is the money."

The new research hints that species from Mexico seem to be unique. Discovering exactly why that is, however, requires obtaining more DNA samples from a wider geographic distribution. "This is more than justification to further screen the biodiversity happening at the tropics through time," Sánchez-Quinto said, "which, ideally, should be carried out by local scientists."

Editor's note: This article was updated at 4:50 a.m. on Sept 11 to correct the dates the mammoths lived from 11,000 to 16,000 years ago to 13,000 to 16,000.

Mammoth quiz: Test your knowledge of the ice age beasts

A fossil ankylosaur discovered in the mountains of Morocco in 2023 was adorned with some of the most frightening armor ever seen.

Researchers suggest that this intimidating array of spikes was sexually selected — like a peacock's tail, it originally evolved to attract mates, rather than to deter predators. By supporting this cumbersome display, the dinosaur, named Spicomellus afer, demonstrated that it was a healthy and worthy partner.

A study analyzing the fossilized remains of the S. afer specimen, which dates to the Middle Jurassic (174.7 to 161.5 million years ago), was published Wednesday (Aug. 27) in the journal Nature.

An earlier rib fragment with fused spikes discovered in 2021, also from Morocco, offered the first evidence of this bizarre species.

"It was so weird that the first thing we did was a CT scan to check that it wasn't fake and that somebody hadn't stuck spines onto the top of the ring," lead author Susannah Maidment, a paleontologist at the Natural History Museum in London, told Live Science. It was in fact real, so she and her team traced the site where it had been found, leading to the 2023 discovery in the Middle Atlas Mountains near Boulemane.

Analysis of the new fossil material confirms that S. afer is the earliest known ankylosaur. The specimen comprises vertebral and rib fragments, parts of the pelvis, and osteoderms — bony deposits in the skin seen in modern reptiles such as crocodiles and alligators.

The fossil assemblage helped the authors to reconstruct how the animal may have looked in life. The low-slung, turtle-shaped animal was approximately 13 feet (4 meters) long, according to Maidment. She noted that the skeleton is not complete and that these measurements are likely inexact.

Long spikes extended from osteoderms on its neck, ringing its head in a fantastical array.

"Ankylosaurs have bony collars around their necks but they're normally a series of flat plates that are fused together and just sit around the neck," Maidment said. "This one had a huge, robust, bony collar the shape of the neck with an enormous pair of meter-long spikes sticking out either side."

The longest of the 10 cervical spikes, extending from either side of the neck, reached at least 34 inches (87 centimeters). Additional spikes stuck out from each rib and were actually part of the skeleton.

"When we see features among living animals that are very hypertrophied and seem to have no function — and would be annoying to carry around — they are related to sex in some way or another," Maidment said.

Still, the researchers suggest that these spikes may have served a secondary, defensive purpose.

They speculate that the end of the tail featured a mace-like array. One of the blade-like spines discovered by the researchers was 17 inches (42 cm) long, and was unlikely to have been attached to any other part of the body.

The tail vertebrae that supported this fearsome armature indicate that the mechanisms for the defensive clubs of Cretaceous ankylosaurs were well underway early in the evolution of this group of dinosaurs. "Handle vertebrae" (closely linked bones with no cartilage between them) helped to stabilize the bony appendages for which later ankylosaurs are known.

The fact that S. afer featured similar bones indicates that its armor was not purely decorative — its tail deterred predators too.

Among ankylosaurs, function may have actually followed fashion. The ankylosaurs of the Cretaceous featured much simpler armor that was almost certainly a defense against a growing range of theropod dinosaurs, crocodilians, snakes and mammals that would have seen them as appealing prey.

Floodwater in Texas has uncovered 15 dinosaur footprints dating to 115 million years ago, researchers say.

The prints were discovered in northwest Travis County by volunteers who were helping to clear up debris from the devastating floods that hit the region in July, Travis County judge Andy Brown, the county’s chief executive, told ABC News. The three-clawed prints — each measuring roughly 18 to 20 inches (46 to 51 centimeters) in length — were then confirmed by paleontologist Matthew Brown on Aug. 5.

"The tracks that are unambiguously dinosaurs were left by meat-eating dinosaurs similar to Acrocanthosaurus, a roughly 35-foot-long (11-meter) bipedal carnivore," Brown, who is the director of vertebrate paleontology at the University of Texas at Austin, told CNN.

Acrocanthosaurus lived during the early Cretaceous period, between 115 million and 105 million years ago and is thought to have been the largest predator in what is now North America at the time, according to the North Carolina Museum of Natural Sciences. These carnivorous dinosaurs looked similar to the later Tyrannosaurus rex and reached similar lengths, although T. rex was significantly taller and heavier.

The tracks are laid out in a criss-cross pattern and may have been made by multiple dinosaurs moving together as a group.

"We aim to return to these sites and document tracks both new and old," Brown told Live Science in an email. "There are new and more precise technologies available to us now than existed in the early 1990s when these sites were last studied, and we can potentially use drones and surface scans to make 3D models of the trackways to better understand them."

Related: A brief history of dinosaurs

Brown hopes that this additional data might tell us more about the dinosaurs' behavior, anatomy and how they moved.

Waterways like Sandy Creek, where the prints were discovered, cut through a layer of rock called the Glen Rose Formation, which is roughly 110 million years old. "That's how we know how old the dinosaur tracks are," Brown said. "It's because they're preserved in rock layers that are that old."

Travis County lies roughly 200 miles (320 kilometers) south of Dinosaur Valley State Park, which is known for its well-preserved dinosaur footprints. Brown said it was fairly common to find dinosaur tracks in central Texas.

"Fossilized dinosaur footprints are relatively common in Travis County, in fact researchers from the University of Texas have documented tracks in this area of Sandy Creek in the past, in addition to the discovery of new tracks along the banks of the creek exposed during this historic storm," he said.

Dinosaurs roamed throughout what is now Texas during the Mesozoic Era (252 million to 66 million years ago), but the majority of footprints and fossils unearthed in the state come from the Cretaceous period (144 to 66 million years ago), when the state was covered in soft mud and a shallow sea, according to Dinosaur Valley State Park.

A "most remarkable" monster's fossilized remains from Jurassic Germany is a never-before-seen species, a new study reports.

The marine reptile, which swam in prehistoric oceans about 183 million years ago, has been given the name Plesionectes longicollum, which translates to "long-necked near-swimmer."

P. longicollum is a type of plesiosauroid, an extinct group of long-necked, carnivorous marine reptiles that swam in Earth's oceans during the time when dinosaurs dominated terrestrial environments. This specimen lived during the early Toarcian age (183 million to 174 million years ago) during the Early Jurassic.

The fossilized specimen is about 10 feet (3 meters) long, similar to the length of an alligator, with its neck accounting for slightly less than half of its total span.

The nearly-complete skeleton of the animal contained remnants of fossilized soft tissue and bone, which enabled scientists to determine that P. longicollum is indeed a newly-discovered species — a conclusion past studies were hesitant to make.

The reptile's bones were originally excavated in 1978 from a quarry in Germany, part of the Posidonia Shale formation, which is known for its "exquisitely preserved fossils," according to the study. "This specimen has been in collections for decades, but previous studies never fully explored its distinctive anatomy," study lead author Sven Sachs, a vertebrate paleontologist at the Natural History Museum of Bielefeld in Germany, said in a statement from the museum.

Related: Oldest tadpole on record was a Jurassic giant

The findings were published in the journal PeerJ on Aug. 4.

"Our detailed examination revealed an unusual combination of skeletal features that clearly distinguish it from all previously known plesiosaurs," Sachs said. The work demonstrated that the Posidonia Shale beds contained a higher degree of reptile diversity than previously thought.

The new specimen is the oldest known plesiosaur from the town Holzmaden in southwest Germany, according to the statement. The animal was not yet an adult when it died, but based on its anatomy, researchers were able to classify it into a new genus and species.

Five other almost complete Plesionectes skeletons have been identified at the Posidonia Shale and include examples of all three major plesiosaur lineages.

"This discovery adds another piece to the puzzle of marine ecosystem evolution during a critical time in Earth's history," study co-author Daniel Madzia, a paleobiologist at the Polish Academy of Sciences, said in the statement. The period when P. longicollum lived "was marked by significant environmental changes, including a major oceanic anoxic event that affected marine life worldwide," he said. The event, which depleted oxygen and spiked acidification in the water, led to a severe loss of marine biodiversity, including an extinction event killing around 5% of global families on land and in the sea.

This fossil is permanently housed at the Stuttgart State Museum of Natural History in Germany.

Researchers have discovered the remains of an ancient shark deep inside the world's longest cave system.

The newly discovered shark, plucked from the walls of Mammoth Cave in Kentucky, lived around 340 million years ago and was equipped with a curved row of teeth that it used for crushing its prey.

Macadens olsoni was a small shark, less than 1 foot (30 centimeters) long, and likely fed on mollusks and worms, according to a statement released by the National Park Service (NPS).

"This discovery is a remarkable addition to our understanding of ancient marine life and underscores the importance of preserving and studying our natural history," Barclay Trimble, the superintendent at Mammoth Cave National Park, said in the statement.

Related: 340 million-year-old 'nail tooth' shark found deep inside Mammoth Cave in Kentucky

The rocks of Mammoth Cave formed around 320 to 360 million years ago and were once beneath a shallow saltwater sea, called the Mississippian Sea. The cave system itself is much younger, and only formed about 10 to 15 million years ago, when water from rivers and streams on the surface sank into the rock and carved out the cave's passages found today, according to NPS.

The exact length of Mammoth Cave is unknown, but explorers have mapped more than 426 miles (686 kilometers) of it, and are still uncovering new passages. It hosts a treasure trove of ancient fish fossils — more than 70 different long-lost species have been identified within its walls so far.

The latest find was extracted from the Ste. Genevieve rock formation and dates back to the Carboniferous period (358.9 million to 298.9 million years ago). The genus name, "Macadens," honors Mammoth Cave, while the species name, "olsoni," honors Rickard Olson, a retired park scientist who has played a key role in documenting these fossils, according to the statement.

The M. olsoni discovery helps researchers better understand the ancient ecosystems now preserved in Mammoth Cave, which may have once been similar to reefs.

"This finding not only enhances our knowledge of ancient marine ecosystems but also emphasizes the critical role of paleontological research in our national parks," Trimble said. "Every discovery connects the past with the present and offers invaluable educational opportunities for students and the public."

Around 100 million years ago, male dinosaurs entered a "mating arena" in Colorado and danced their hearts out to attract females, a new study suggests.

Researchers uncovered a series of mating display scrapes preserved on the surface of rocks at Dinosaur Ridge in Jefferson County, Colorado. The state is known for dinosaur track sites, with previous studies suggesting that dinosaurs returned to these mating spots over successive breeding seasons.

The latest marks identified at Dinosaur Ridge suggest that multiple individuals participated in mating display behavior there during the Cretaceous period (145 million to 66 million years ago) and allow the ridge to be classed as a "display arena," or lek, according to the new study, published online on June 4 in the journal Cretaceous Research.

The scapes were left by theropods, a group of bipedal dinosaurs that included Tyrannosaurus rex. Study lead author Caldwell Buntin, a lecturer in Earth science at Old Dominion University in Virginia, told Live Science that they don't have any direct evidence of what species left the marks, but it was a small therapod, around the size of a modern-day ostrich.

Researchers believe that the dinosaurs showed off to potential mates by jabbing their claws deep into the sand, dragging their feet and kicking up sand behind them. Buntin noted that the animals would alternate between their two feet when kicking up sand and had different moves.

"We can tell they had two moves so far, one walking backwards and one moving side to side," Buntin said in an email. "If they were really excited they would step a few feet backwards and repeat the motion, which usually erases the back half of each earlier set of scrapes. When this happened 3 or more times a few of these show a counter-clockwise turn, kind of like the moonwalk with a little spin."

Related: Mysterious 'runner' dinosaur a sign there are more Jurassic secrets to unlock beneath western US

"When moving side-to-side, they would take a step or two to the side, face the same direction, and repeat their scrape movements," Buntin said. "This is usually recorded by two sets of scrapes right next to one another, or one and a half sets of scrapes if they only took a half step over."

Lekking is a common behavior among modern birds. For example, male greater sage-grouse (Centrocercus urophasianus) perform an elaborate sunrise display each spring, inflating air sacks on their chests and generally strutting their stuff for the attention of females.

The lek at Dinosaur Ridge dates back to the Cretaceous period's Cenomanian age (100.5 million to 93.9 million years ago). Buntin and his colleagues used drones to capture high-resolution images of the site and identified a total of 25 new scrapes on two surfaces at the ridge.

"It was very exciting to see the new scrapes in the imagery when we processed it!" Buntin said. "Originally only 2 or 3 of the new traces were immediately evident, but within an hour or so we had noticed almost a dozen new of the scrapes. It was quite surreal."

Fossilized bite marks suggest there could have been a dramatic tussle between a gigantic terror bird and an even more massive crocodile around 12 million years ago.

Phorusrhacids, commonly known as "terror birds," were apex predators that terrorized prey in the ancient ecosystems of South America. While these flightless carnivores had little to fear on land, a new study, published Tuesday (July 22) in the journal Biology Letters, indicates that they weren't necessarily safe around water.

Researchers analyzed tooth marks on the leg bone of one of the largest terror birds ever discovered — estimated to have stood more than 9 feet (2.7 meters) tall — unearthed at the La Venta fossil site in Colombia. The team concluded that a 15-foot-long (4.7 meter) caiman was likely responsible for the marks.

"We have learned that terror birds could also be preyed [upon] and that even being an apex predator has risks," study lead author Andrés Link, a paleontologist and biologist at the University of the Andes in Colombia, told Live Science in an email.

The study doesn't rule out the possibility that the terror bird simply died near a body of water and was subsequently munched on by the caiman, making it a case of scavenging rather than hunting.

Related: Why giant moa — a bird that once towered over humans — are even harder to de-extinct than dire wolves

Researchers first unveiled the terror bird fossil in a study published last year. The study's authors said at the time they suspected a crocodilian killed the bird, but they hadn't yet published an analysis of the four tooth marks found on the bone.

For the new study, the researchers evaluated the bite mark by creating detailed 3D images of the fossil. The bone marks had no signs of healing, while the size and shape of the marks were consistent with those delivered by a caiman that was around 15.1 to 15.8 feet (4.6 to 4.8 m) long, according to the study.

The team hypothesized that La Venta's largest ancient caiman species, Purussaurus neivensis, was behind the bite. However, the individual responsible would have been a subadult, and not yet fully grown. Link told Live Science that P. neivensis could grow up to around 33 feet (10 m) long. "It was a massive animal!" he said.

Without direct evidence of the caiman eating the terror bird, the findings represent an anecdotal account of an aquatic apex predator feeding on a land apex predator during the middle of the Miocene epoch (23 million to 5 million years ago).

"In my opinion this study contributes to understanding the diet of Purussaurus, the landscape of fear near the water bodies [at] La Venta during the middle Miocene and the complex ecological interactions in the protoAmazonian ecosystems of [tropical] South America," Link said.

A biotech company that claims to have brought dire wolves back from extinction has announced plans to resurrect giant extinct birds called moa. However, experts say that dire wolves were never truly resurrected, and that moa will be even harder to de-extinct.

Earlier this month, Texas-based Colossal Biosciences said it had teamed up with filmmaker Sir Peter Jackson and Indigenous partners to bring back the 12-foot-tall (3.6 meter) South Island giant moa (Dinornis robustus) and other moa species. These flightless birds roamed New Zealand until they were hunted to extinction by early Māori settlers around 600 years ago.

The new project will be coordinated by the Ngāi Tahu Research Centre, a joint venture between the main Māori tribe (iwi) on the South Island of New Zealand and the University of Canterbury in Christchurch. It's a multifaceted project that aims to combine traditional Māori knowledge, wildlife conservation and genetic engineering-driven de-extinction.

However, the project has already come under fire. Critics have highlighted that some Māori iwi oppose de-extinction, while several scientists have argued that genetically modifying living animals can't bring back lost species. The scientific criticism is similar to the commentary after Colossal unveiled its "dire wolves" — a species that went extinct more than 10,000 years ago.

Colossal's "dire wolves" are genetically modified gray wolves (Canis lupus) with 20 gene edits. The company claims they are dire wolves (Aenocyon dirus) because they have some observable traits identified in the dire wolf genome, such as increased size and a white coat. However, genetically, they're still mostly gray wolves. The same will be true for the living animal Colossal modifies for the moa project — but for moa, it's even more complicated.

Related: T. rex researchers eviscerate 'misleading' dinosaur leather announcement

Moa's closest living relatives are a group of South American birds called tinamous. The largest tinamou species is smaller than most domestic chickens, so is minuscule compared to South Island giant moa. Australia's emus (Dromaius novaehollandiae) are the next closest relative, but while these large flightless birds are physically more similar to giant moa, they're still not as big, growing to an average of 5.7 feet (1.75 m) tall. Both of these living relatives also separated from moa a long time ago.

"The common ancestor of the moa and tinamou lived 58 million years ago, while the common ancestor of moa and emu lived 65 million years ago," Nic Rawlence, director of the Otago Palaeogenetics Lab at the University of Otago in New Zealand and a critic of the moa plan, told Live Science in an email. "That’s a lot of evolutionary time."

To put that in context, dire wolves only split from modern wolf-like canids — the group that includes gray wolves — around 5.7 million years ago (or even more recently at 4.5 million years ago, according to a recent preprint involving some of Colossal's scientists). That means moa had a lot more time to evolve unique traits.

Rawlence explained that moa and their closest living relatives descended from a group of small flying birds called lithornids. These animals lived around the world and gave rise to different groups that independently lost the ability to fly. As Rawlence puts it, these flightless birds were "filling the job vacancies in the ecosystem left by the extinction of the dinosaurs."

Moa and emu lost flight through a process called convergent evolution, whereby different organisms evolve similar traits. That means, according to Rawlence, that the physiological and developmental mechanisms behind their body plans evolved independently, potentially via different genetic routes, which poses a challenge when it comes to bringing moa back.

"Genetically engineering specific genes in an emu to match a moa could have dire developmental consequences given this independent and convergent evolutionary history," Rawlence said.

Live Science asked Colossal whether there were any health risks associated with genetically engineering living animals to be more like extinct animals. Colossal’s chief science officer, Beth Shapiro, told Live Science that the company was certified by the American Humane Society and that animal welfare was a priority in their work.

"We thoroughly evaluate health risks of any proposed edit before selecting them for our final list of edits," Shapiro said in an email.

Colossal's moa de-extinction plan

Before Colossal begins creating its modern-day moa, the company aims to sequence and rebuild the genomes of all nine extinct moa species, while also sequencing high-quality genomes of their closest living relatives. This will allow Colossal to identify the changes that led to the moa's unique traits, including their large body size and lack of wings, according to Colossal's website.

The researchers will then use primordial germ cells, the precursors of sperm or egg cells, from living species to "build a surrogate bird" and make genetic changes to create birds with moa traits. The company needs both male and female surrogates to carry the sperm and egg of their "moa," to then produce the genetically modified offspring.

Colossal's website states that emus' larger size makes them a more suitable surrogate than tinamous. However, details on this part of the process are limited. Shapiro told Live Science that they were "still in the process of selecting the surrogate species for moa de-extinction."

Emus lay large green eggs, around 5 inches (12 cm) long and 3.5 inches (9 cm) wide. Still, that's nothing compared to a South Island giant moa egg, which were 9.5 inches (24 cm) by 7 inches (17.8 cm).

"A South Island giant moa egg will not fit inside an emu surrogate, so Colossal will have to develop artificial surrogate egg technology," Rawlence said.

Colossal briefly mentioned artificial eggs during its moa announcement, but didn't provide details on this part of the process. Live Science asked Colossal whether they could explain how Colossal will hatch a South Island giant moa.

"Our exogenous development team is exploring different strategies for artificial egg incubation, which will have application both for moa de-extinction and bird conservation work," Shapiro said in an email.

Researchers have pulled the perfectly-preserved skull of an ice age horse from a mine in Yukon, Canada, new pictures show.

Based on the soil around the skull and the depth of sediments where it was found, experts estimate that the horse lived about 30,000 years ago — but more precise radiocarbon dating could narrow this down, a spokesperson for the Yukon Paleontology Program said.

Scientists have identified more than 50 ice age horse species to date, but it remains unclear which one the skull belongs to. Horses that lived in what is now Yukon during the last ice age (2.6 million to 11,700 years ago) were relatively small, standing about 4 feet (1.2 meters) tall at the shoulders, Cameron Webber quoted experts as saying in an email to Live Science.

"While the physical characteristics of the skull and the size and shape of the teeth can provide clues to its evolutionary history, the specific species of this horse cannot be identified without more in-depth genetic information," Webber said. "Ancient DNA analysis will be needed if an accurate species identification for this find is desired."

Related: 'I knew they were something special': New York homeowner discovers mastodon jaw fossils in backyard

Researchers found the skull in a mine in the Klondike, a region in western Yukon. Only parts of the lower jaw and upper skull were initially visible above the mine's frozen ground, so the team returned the next day with more tools and water to melt the skull out, representatives of the Yukon Beringia Interpretive Center, a museum in Whitehorse, Canada, wrote in a Facebook post.

Miners helped the researchers extract the "beautifully preserved" skull by directing their water hoses over the skull, the representatives wrote.

"What emerged was a complete horse skull," they wrote. "The presence of canines tells us this horse was likely male, and because they were only partially erupted, we know he was likely a teenager when he died."

It is unclear whether researchers will date the skull and analyze its DNA to determine the species.

Horses lived in North America between about 50 million and 11,000 years ago, when they went locally extinct. Europeans reintroduced horses following the 15th century, and the animals rapidly spread throughout the continent.

Last ice age quiz: How much do you know about Earth's frosty past?

A giant, flightless bird that roamed New Zealand before going extinct about 600 years ago is the next species on a controversial list of "de-extinction" targets from the biotechnology company Colossal Biosciences.

Colossal announced on Tuesday (July 8) that its scientists and local Indigenous partners will "bring back" the South Island giant moa (Dinornis robustus) through genetic engineering within the next 10 years. D. robustus stood up to 12 feet (3.6 meters) tall and was the largest of nine known species of moa, all of which are thought to have gone extinct due to hunting by humans.

"We're bringing back avian dinosaurs," the company said in a post on Instagram.

Colossal previously claimed to have brought back the dire wolf (Aenocyon dirus), an ice age predator that went extinct more than 10,000 years ago — but the reveal in April drew criticism from many experts, who said the animals were merely gray wolves with a few, cherry-picked dire wolf traits. Colossal also has plans to "resurrect" the woolly mammoth, the dodo and the thylacine (a wolf-like creature also known as the Tasmanian tiger), but these projects are similarly shrouded in controversy.

"We have numerous taxa going extinct now so it is unacceptable that this is seen as okay just because it may be possible to regenerate an animal in the future," Trevor Worthy, a vertebrate paleontologist and associate professor at Flinders University in Australia who is not associated with Colossal, told Live Science in an email.

Colossal's new announcement immediately attracted criticism from researchers, who denounced the company's failure to acknowledge that the bird it will eventually create will not be a moa, but rather a hybrid with moa-like characteristics.

Related: Instead of 'de-extincting' dire wolves, scientists should use gene editing to protect living, endangered species

"There is no current genetic engineering pathway that can truly restore a lost species, especially one missing from its ecological and evolutionary context for hundreds of years," Philip Seddon, a professor of zoology at the University of Otago in New Zealand, told the country's Science Media Center (NZSMC). "Any end result will not, cannot be, a moa — a unique treasure created through millennia of adaptation and change."

Following the dire wolf announcement, Colossal's chief scientist Beth Shapiro clarified in an interview with New Scientist that the animals are actually "gray wolves with 20 edits" and that "it's not possible to bring something back that is identical to a species that used to be alive." Shapiro also argued that Colossal had never tried to hide these facts, but when Live Science contacted Colossal for comment, a spokesperson doubled down on the company's original claim that it has brought back the dire wolf.

In the moa announcement, Shapiro says Colossal will "bring the moa back to life" and Ben Lamm, the company's co-founder and CEO, says scientists will "return it back to the ecosystem."

"Despite Colossal Biosciences' eventual reframing of dire wolf de-extinction as actually creating an ecological replacement using a genetically modified grey wolf, there is no hint in their recent press release that the best we can hope for is an ecological replacement for a New Zealand moa," Seddon told NZSMC.

To recreate the giant moa, scientists will extract DNA from the remaining bones of all nine species and compare it to the DNA of living birds, Shapiro told Time Magazine. Researchers will then be able to pinpoint the specific genetic characteristics of moas and make those changes in the genome of either an emu or a tinamou, the two closest living relatives of moas, she said.

"It makes sense to use tinamous and emus as templates from which to align DNA of moa," Worthy said in his email. "Much work on DNA has shown tinamous are the sister species to moa. Emu are a reasonably close relative as well."

Genetically modified tinamou or emu cells will then be implanted into a surrogate from one of the two birds and left to gestate. Hatchlings will not be released into the wild nor kept in a zoo, according to the announcement, suggesting the birds will live out their lives in a fenced-off nature reserve.

Should the birds escape, Worthy said they wouldn't pose a danger to humans. "Moas wouldn't see humans as a threat, unless perhaps you tried to hug it, and in scaring it likely you would get kicked and quite likely, badly hurt," he said.

Colossal says moa de-extinction will bring benefits for endangered birds along the way; for example, it could inform the development of artificial eggs, which, in turn, may help preserve endangered species.

"There will be undoubted great advances in knowledge along the path towards de-extinction," Worthy said. "We will get [unprecedented] knowledge of the target animals' DNA and for extinct groups such as the moa this will potentially [be] very interesting regarding their evolution, relationships, etc."

But creating an animal that is only like the extinct species in appearance remains "straight out of Frankenstein," Stuart Pimm, a professor of conservation ecology at Duke University in North Carolina, told Time Magazine.

Researchers have unearthed the oldest pterosaur ever discovered in North America and named it the "ash-winged dawn goddess."

The 209 million-year-old pterosaur was among a cache of more than 1,000 Triassic fossils extracted from rocks in the Petrified Forest National Park in Arizona. Eotephradactylus mcintireae is partly named after volcanic ash found in the fossil bed and Eos, the Greek goddess of the dawn, because it evolved near the beginning, or dawn, of pterosaurs' evolutionary history.

Pterosaurs, informally called "pterodactyls," were flying reptiles that dominated the skies during the age of dinosaurs. The group produced many giants, some with wingspans stretching to around 36 feet (11 meters), but E. mcintireae and the other early members were tiny by comparison.

"This pterosaur would be the size of a small seagull, and could have sat on your shoulder," study lead author Ben Kligman, a paleontologist at the Smithsonian's National Museum of Natural History in Washington, D.C., told Live Science in an email.

E. mcintireae was just one member of a lost ecosystem described in the study, published Monday (July 7) in the journal PNAS. The cache of Arizona fossils also included giant amphibians, freshwater sharks, armored crocodile-like creatures and one of the oldest known turtle fossils.

These finds help researchers understand what animals were alive before the violent mass extinction event, likely triggered by volcanic eruptions, that brought the Triassic period to a close around 201 million years ago.

Related: Giant pterosaurs weren't only good at flying, they could walk among dinosaurs too

Towards the end of the Triassic, northeastern Arizona was located just above the equator in the middle of the supercontinent Pangaea. At the time, the semi-arid landscape was marked with small rivers and channels that were likely prone to flooding, according to a statement released by the Smithsonian. Researchers suspect that a flood washed over the tiny pterosaur and other animals living in the region at the time, burying their bodies in sediment and ash.

A team of scientists first discovered what remained of the Triassic bonebed in 2011. The fossils were mostly small and delicate, so rather than trying to excavate them in the field, the team extracted large chunks of sediment and worked through them in labs. Many chunks went to the Smithsonian National Museum of Natural History, where volunteers spent thousands of hours carefully extracting the fossils. A volunteer named Suzanne McIntire extracted a jaw belonging to the pterosaur in 2013 — the species name mcintireae honors her discovery.

Kligman began working on the fossils in 2018, after the jaw had been discovered, and said he doubted the fossil was a pterosaur at first — at the time, researchers had only found one early pterosaur in North America, and none had ever been found in sediment deposited in a river.

"When I finally examined the jaw my doubts were put to rest — the distinctive teeth and jaw anatomy was unmistakably from a pterosaur," Kligman said. "I was most surprised by the fact that a delicate, tiny jaw like this one had not been destroyed by the movement of river gravel prior to it being fossilized, suggesting that the bonebed was preserving a unique fossilization setting."

The bonebed revealed a community of evolutionary newcomers, such as pterosaurs and turtles, sharing the landscape with each other and more ancient animals, such as giant amphibians, before the latter went extinct at the end of the Triassic.

"The presence of the pterosaur Eotephradactylus living and interacting in a community alongside groups like frogs, lizard relatives, and turtles is the first occurrence of this community type in the fossil record — these groups are commonly found living together in post-Triassic communities from the Jurassic and Cretaceous, however they had never been found together preceding the end-Triassic extinction event 201 million years ago," Kligman said.

Dinosaurs are hitting movie theaters this summer with "Jurassic World Rebirth" debuting on Wednesday (July 2). The series that started more than 30 years ago with "Jurassic Park" is still one of the only major live action blockbuster franchises that has propelled dinosaurs to the big screen. So, what's it like being a paleontologist who advises Hollywood on these Mesozoic creatures?

Steve Brusatte, a vertebrate palaeontologist and evolutionary biologist at the University of Edinburgh in Scotland, is the scientific advisor to the "Jurassic World" movies, including the latest, which stars Scarlett Johansson, Mahershala Ali and Jonathan Bailey. Live Science emailed Brusatte several questions to get to the meat of the matter: What's his favorite scene from "Jurassic World Rebirth," what's an inaccuracy from the "Jurassic Park" films he'd like to correct, and, most importantly, if a dinosaur were to attack, which one would he prefer?

Hannah Osborne: How different would the first films be now knowing what we know about dinosaurs today?

Steve Brusatte: The first Jurassic Park came out in 1993, and in the more than 30 years since, we've learned a tremendous amount about dinosaurs. There have been something like 1,000 or more new dinosaur species discovered since then. CT scanning and molecular sampling of fossils have revolutionized our understanding of how dinosaurs grew, moved, reproduced, hunted and socialized. And we now know that a lot of dinosaurs had feathers. But still, even with all of that, the image of dinosaurs in the original film is not too far removed from what we know today. Those dinosaurs still feel realistic in their postures and behaviors. They still look good on the screen. The film has aged well!

But of course, we can incorporate the newer scientific discoveries into the new films.

HO: If you could go back in time to study one period of the Mesozoic in person, which would it be?

SB: Although T. rex will always be my favorite dinosaur, and it lived right at the end of the Age of Dinosaurs, in the closing moments of the Cretaceous period 66 million years ago, my choice would be another period entirely: The Triassic. The time spanning between about 252 [million] and 201 million years ago, bookended by two of the worst mass extinctions in Earth's history, each caused by apocalyptic volcanic eruptions.

This was the time of the supercontinent Pangaea, when all of the world's land was gathered together. And on this supercontinent the very first dinosaurs took their very first steps. These pioneering dinosaurs looked nothing like T. rex or Brontosaurus. They were merely the size of cats or dogs. But they were smart, and ran fast, and lived active and energetic lifestyles. How glorious it would have been to see them — the forebears of the dinosaur dynasty to come.

HO: What's the biggest inaccuracy from past Jurassic Park films you'd like to set the record straight on?

SB: It has to be the feathers. The original Jurassic Park rampaged with all sorts of green scaly dinosaurs, which looked like overgrown lizards or crocodiles. That was in line with what we knew about dinosaurs at the time, in 1993. But then, three years later, in China, a farmer out working his fields stumbled upon a gorgeously preserved dinosaur skeleton embedded in rock. Petrified feathers surrounded the bones. This was the first of many discoveries of similar dinosaurs, rapidly buried by volcanic eruptions, covered in feathery fluff.

We now know that many dinosaurs were fuzzy, and some, like the real Velociraptor, even had wings on its arms. In an alternative history, those first feathered dinosaurs would have been found a few years earlier, and Steven Spielberg could have put some feathers on his Velociraptors.

Related: Jurassic Park movies ranked, worst to best

HO: How does the science advisor process work? Does the studio come up with ideas and then you say yes/no, or vice versa? At what point do you get involved?

SB: My job is advisory. I am always on call, whenever the director, or artists or writers have any questions about dinosaurs. I see myself as an advocate for the science, and my mission is to make sure that the science behind dinosaurs is always there, in the ears of the creative geniuses who are writing and making the films. Most of my work happens early on, when the script is being ironed out and the designs for the dinosaur characters are being developed. It entails a lot of Zoom chats, phone calls and emails. A lot of talking, really.

Me giving feedback on ideas, whether it is a plot line, or more usually, the design of a dinosaur. It's not my job to approve or veto anything, but just to give my opinion. And I know that opinion will be weighed against many other things as the film takes shape.

HO: How do you balance entertainment with scientific accuracy?

SB: Ultimately these films are summer Hollywood monster movie blockbusters. They are not nature documentaries. They are meant to entertain. And more than anything, I am impressed and thankful that the Jurassic Park and Jurassic World series has always had paleontology advisors, for all seven films. They don't need to do this. I don't think most sci-fi films in outer space have astrophysics consultants. But the Jurassic franchise has always valued real dinosaurs.

Of course, scientific accuracy is just one component to making a dinosaur character memorable on screen. The character has to be recognizable, it has to have personality, it has to carry a story line, and it has to be dramatic. The same way that biopics of famous humans might exaggerate their features or personalities for dramatic effect, the Jurassic dinosaurs might not hew exactly to scientific precision. And I am OK with that. Because after all, we are talking about extinct species that lived millions of years ago. Nobody has seen these dinosaurs alive. There is so much we don't know about how they looked and behaved. So we always need some artistic license when it comes to imagining them.

HO: How do you become a science advisor on a big movie like this?

SB: By a stroke of incredible luck and good fortune. It's not like there is an application process. Instead, the timing just worked out. The eminent paleontologist Jack Horner served as consultant for the first five films, but then he retired. When Colin Trevorrow, the director of two of the Jurassic World films, was starting to develop Dominion in 2018, he had read a book I had recently written (The Rise and Fall of the Dinosaurs). He reached out, and I obviously thought his email was a joke — a trick being played by one of my colleagues or students. But we connected and it turned out to actually be Colin, and then we met up in Edinburgh where I live, and had a great chat, and he offered me the position. And then I was thrilled to return for Rebirth, as Colin handed the reins over to Gareth Edwards to direct the latest installment.

HO: To have a fresh supply of villains, the Jurassic World franchise keeps inventing new dinosaurs that are scarier than T. rex. Do you think there are any real-life dinosaurs that are actually scarier than T. rex?

Short answer, no. I think T. rex was the ultimate dinosaur. It was a bus-sized monster, with a head the size of a bathtub, with over 50 railroad spike teeth that could crush the bones of its prey. And it was smart, with a big brain for a dinosaur, and keen senses of smell and hearing and vision. It doesn't get any badder than that.

SB: What's your favorite dinosaur in the new movie and why?

I love the titanosaurs, the giant long-necked sauropods. They are simply awesome — in the literal sense of the word. Colossal creatures heavier than jet airplanes, with necks that could reach several stories into the sky. And the way they are portrayed in the film, the way Gareth celebrates their massive size and scale, it is just mesmerizing. My favorite scene in the film is when the paleontologist, played by Jonathan Bailey, encounters these dinosaurs for the first time and just emotionally gets lost in them. It's beautiful. It's how I would imagine I would react if I saw a real-life giant dinosaur.

HO: If you had to be eaten/killed by a dinosaur, which one would it be and why?

SB: I suppose T. rex, because it would be a quick death. Crushed in those jaws and swallowed.

Editor's note: This Q&A has been lightly edited for style.