Latest news with #Gorgosaurus
National Geographic
23-07-2025
- Science
- National Geographic
Different dinosaur species may have really traveled together like in the movies
A newly discovered trove of fossilized footprints provides what may be the first evidence of prehistoric diversity in dinosaur herds, though not everyone is convinced. A herd of ceratopsians (Styracosaurus albertensis) accompanied by an ankylosaur (Euplocephalus tutus) walk through an old river channel under the watchful eyes of two tyrannosaurs (Gorgosaurus libratus). Illustration by Julius Csotonyi Across the African savanna, zebras and wildebeests travel together in massive herds often peppered with impalas and gazelles. The larger the herd, the safer its members are from predators like lions, hyenas and African wild dogs. Scientists have wondered whether dinosaurs similarly engaged in mixed-species herding behavior. Children's movies like ' The Land Before Time ' series and ' Dinosaur ' (2000) often depict motley crews of dinosaurs migrating together, like apatosaurs and triceratops or iguanodons and parasaurolophus (despite often living in different time periods). But evidence that different dinosaur species actually travelled with each other was lacking in the fossil record. Now, paleontologists working in the badlands of Dinosaur Provincial Park in Alberta, Canada, have uncovered fossilized footprints they say provide the first evidence of different species of dinosaurs herding together—though not everyone is convinced. The finding was published Wednesday in PLOS One . The 76-million-year-old footprints tell the story of a small group of horned dinosaurs, called ceratopsians, that may have formed a Lord of the Rings-esque traveling party with an armored ankylosaurid and, perhaps, a small two-legged theropod. And like Tolkien's famous fellowship, this band of travelers may have been stalked by fearsome foes: a pair of large carnivorous tyrannosaurs. RTMP technician working on Skyline tracksite Photograph by Dr Brian Pickles, University of Reading In the summer of 2024, Brian Pickles , a paleontologist at the University of Reading in England and his colleague Phil Bell were searching for fossils in the park when they came across something strange sticking out of the ground. 'We'd gone out prospecting for bones and weren't having much luck,' says Pickles. But then Bell, a paleontologist from the University of New England in Australia, came across a raised rim of iron stone. 'He started poking around and realized that it was a dinosaur footprint.' The 48 hours that followed the find were a whirlwind of frantic excavation and profound discoveries that culminated in what he calls 'a revolution in dinosaur paleoecology at Dinosaur Provincial Park.' In a patch of land roughly the size of two parking spaces, the team was able to excavate over a dozen fossilized footprints. Unlike other dinosaur track sites where footprints often overlap, these tracks were evenly spaced and showed no signs of crowding. Based on their size, shape, and direction, the researchers concluded they were likely made by a mixed-species group of at least five dinosaurs walking together. The team also found the fossilized footprints of two large tyrannosaurs that may have been walking side-by-side near the herd. Digital Elevation Model of Skyline tracksite (elevation scale in m) and key tracks (scaled to relative elevation) Illustration by Dr Brian Pickles, University of Reading Were these apex predators working together to hunt? And was the herd formed as a way to defend against such predation? In the grasslands of Africa, lions will often follow mixed species herds of herbivores and work together to hunt them. Could these footprints have captured a similar situation unfolding? 'It's quite evocative to think of this situation as being similar to what we see on the African plains today,' says Pickles. 'We don't know the specific timing. The tyrannosaurs could have been there first.' 'Weak feet?' Some researchers not involved in the work questioned the team's conclusions. Anthony Romilio , a paleontologist at the University of Queensland in Australia, says that although some dinosaurs likely did form mixed-species herds, he disagrees with how the authors interpreted the footprints. 'As researchers, we're naturally drawn to the possibilities these fossils offer—but that excitement can sometimes lead to interpretive overreach,' Romilio says. In his view, the ceratopsian and ankylosaurid tracks look similar in shape, and he thinks they are more likely to be poorly preserved footprints of large-bodied hadrosaurs. 'That interpretation may not be as headline-grabbing, but it aligns better with what we know from both fossil footprints and trackways,' he says. Christian Meyer, a paleontologist from the University of Basel in Switzerland, is also skeptical, and calls the findings "speculative." "I find that the preservation of the tracks, including their taxonomic assignment, is on weak feet, as there are no complete trackways preserved that show also the walking pattern," he says. "Moreover, the interpretation of mixed herding is—given the facts—in my view a bit overstretched." Since the excavation that sparked this new study, Pickles and his colleagues say they have found over ten additional dinosaur trackways. With this many trackways, Pickles says, figuring out whether some dinosaurs formed mixed-species herds is just the beginning. 'There's potentially a lot more going on there than we've been able to expose so far,' he says.
National Geographic
12-06-2025
- Science
- National Geographic
Scientists discover ‘dragon prince' dinosaur, the T. Rex's missing ancestor
Khankhuuluu mongoliensis was slender with features like no other member of the tyrannosaur family tree. This illustration depicts how the slender Khankhuuluu mongoliensis may have appeared as it roamed Mongolia during the Cretaceous period. The newest addition to the tyrannosaur family, the discovery of this "dragon prince from Mongolia" sheds light on the origins of Tyrannosaurus rex. Illustration by Julius Csotonyi Tyrannosaurus rex is a carnivorous icon. Exceeding 40 feet in length and nine tons, the bone-crushing giant stands out as the largest and last of its meat-eating family. Now a new and far smaller tyrannosaur is filling in the famous dinosaur's evolutionary backstory. The newest addition to the tyrannosaur family tree is named Khankhuuluu mongoliensis, which translates to 'dragon prince from Mongolia.' Described this week in the journal Nature, the dinosaur has been identified for the first time from two partial skeletons that include skull bones, vertebrae, part of the hips, and limb bones. Altogether, the pieces reveal a slender tyrannosaur that roamed Cretaceous Mongolia about 86 million years ago and was about 13 feet long—or about the size of juvenile T. rex that would stalk North America 20 million years later. In fact, Khankhuuluu even looked like a juvenile of later, larger tyrannosaurs, with round eye sockets, blade-like teeth, and long, shallow jaws better suited to biting fast rather than hard. (T. rex had lips, upending its enduring pop culture image.) Khankhuuluu does more than simply add another dinosaur to the ever-growing roster of dinosaurs. 'Khankhuuluu gives us the origin story of tyrannosaurs,' says University of Calgary paleontologist and study co-author Darla Zelenitsky. Comparing the fossils of mature Khankhuuluu (a, d, g) with fossils of mature Gorgosaurus (c, f, i) and juvenile Gorgosaurus (b, e, h) provides new insights into the evolutionary lineage between the smaller-bodied tyrannosauroids, such as Khankhuuluu, and the larger eutyrannosaurians like Gorgosaurus and Tyrannosaurus. Silhouettes compare the sizes of Khankhuuluu (left) with a juvenile (right) and adult (middle) Gorgosaurus. Scale bars, 5 cm (individual elements) and 1 m (silhouette). Illustration by Voris et al. (2025), Nature In the early 1970s, Mongolian paleontologist Altangerel Perle found a pair of partial tyrannosaur skeletons in the eastern part of the country. The bones seemed similar to a small tyrannosaur that had been named before, Alectrosaurus. But when University of Calgary paleontologist and study co-author Jared Voris studied the bones during a research trip to Mongolia in 2023, he soon realized that the bones did not belong to Alectrosaurus at all. The bones from the two skeletons belonged to a new form of tyrannosaur that had been waiting to be discovered in collections for half a century. 'It had features like a hollow air chamber in side its nasal bone, which no other tyrannosaur species has,' Voris says. The fossils deserved a new name and have been recategorized as Khankhuuluu. Voris has found tyrannosaurs hiding in plain sight before. In 2020, Voris and colleagues named the 80 million-year-old tyrannosaur Thanatotheristes from bones assigned to another species found in Alberta. ("Reaper of Death" tyrannosaur discovered in Canada.) The finds are part of a burgeoning array of tyrannosaur discoveries. Instead of a simple line of evolution from early tyrannosaurs to T. rex, paleontologists have uncovered a wildly branching evolutionary bush of different tyrannosaur subgroups that came and went through the Cretaceous. The glut of new tyrannosaur species is allowing experts to piece together how big tyrannosaurs, including the gigantic T. rex, evolved and spread across vast stretches of the planet. What the 'dragon prince' tells us about the evolution of T. rex When compared to other tyrannosaurs, the researchers found that Khankhuuluu is a close relative of the broader group of tyrannosaurs that include Gorgosaurus from Alberta, the bumpy-snouted Alioramus from Mongolia, and the iconic T. rex. The new family tree, as well as where the fossils were uncovered, create an updated picture of how tyrannosaurs evolved over 20 million years. 'It is a pivotal species in understanding the evolutionary success of T. rex and its relatives,' says University College London paleontologist Cassius Morrison, who was not involved in the new study. In particular, the new analysis reveals how tyrannosaurs evolved into many different species as the carnivores wandered into new landscapes. Sometime around the time of Khankhuuluu, Voris and colleagues propose, such small, slender tyrannosaurs were dispersing from prehistoric Asia into North America over a land bridge. 'Tyrannosaurs evolved into those giant apex predators and diversified very rapidly across North America,' Voris says, the first of what Zelenitsky calls 'two explosions of tyrannosaurs.' Some of the predators remained slender and chased smaller prey while others became bulkier and hunted larger dinosaurs, and they roamed habitats from southern California to New Jersey. (See how these fierce dinos evolved in our pages over 100 years.) The new study suggests, however, that the direct ancestors of T. rex, did not evolve in North America. Voris and colleagues propose that around 79 and 78 million years ago at least one lineage of tyrannosaurs ventured back into Asia. The researchers know this because of the close relationship of two tyrannosaur groups that at a glance might seem very different. When tyrannosaurs returned to Asia during this period and underwent their second explosion, one group was relatively slender and had long snouts decorated with small horns, like the 'Pinocchio' dinosaur Qianzhousaurus. The other group began to grow larger, with deep skulls adept at crushing bones, like Tarbosaurus. T. rex evolved from ancestors in the second group, a lineage of bone-crushers that once again crossed the land bridge back into North America between 73 and 67 million years ago—making T. rex a new form of predator that arrived from another continent. 'The new analysis provides strong support that the ancestors of T. rex evolved from a group of tyrannosaurs that ventured back to Asia after they had undergone an evolutionary radiation in North America,' Morrison says. Ultimately, the study suggests that the rise of one of Earth's largest carnivores was due to a back-and-forth between North America and Asia that took place over a period of 20 million years. Had a devastating asteroid impact not abruptly ended the Cretaceous 66 million years ago, tyrannosaurs would have undoubtedly kept changing.
