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New Dino Species Found on Dusty Shelf |
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John Pickrell for National Geographic News |
| July 10, 2003 |
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Neglected for 20 years on the dusty shelves of a South African university, paleontologists have re-discovered the 215-million-year-old fossils bones of one of the earliest giant dinosaurs. The two-ton (1.8 metric ton) species of sauropod, previously unknown to science, is the oldest known ancestor to lumbering herbivorous giants such as the well-known brachiosaurs of the Jurassic. The 215 million-year-old specimen, named Antetonitrus ingenipes, is significantly older than any previously known sauropod, a class of plant-eating dinosaurs with four legs and long necks. The new dino helps scientists to bridge a gap in their knowledge of where sauropods came from and how they evolved to be so large. The fossil bones were first unearthed in 1981 on central South African farmland by veteran fossil hunter James Kitching. But the fossils were initially misidentified. Researchers cleaned the fossils and left them on a shelf at the Witwatersrand University's Bernard Price Institute for Palaeontological Research in Johannesburg (BPI). It wasn't until 20 years later, when young Australian dinosaur researcher Adam Yates, visited the institute in 2001 that the blunder was realized. "Mounting Thrill" "It didn't take me very long to realize their significance…it was very exciting indeed," Yates told National Geographic News. "First there was the pure joy at seeing such beautifully preserved and relatively complete remains," he said. "Then the mounting thrill as it began to sink in that this creature was very advanced for its time and so much more like the giant sauropod dinosaurs of the Jurassic than any of its Triassic contemporaries." The partial skeleton (minus its skull, neck, and most of its ribs) is all that remains of a juvenile sauropod. The giant would have weighed two ton (1.8 metric tons) or more in real life, said Yates, now based at the BPI. The animal would have measured eight to ten meters (26 to 33 feet) in length—possibly longer when full grown—and two meters (6.5 feet) high at the hips. The bones were found in sediments roughly dated to 220 to 215 million years ago, during the late Triassic period, the time between 251 and 200 million years ago that saw the dawning of the age of the dinosaurs. The previous title holder for oldest sauropod, Isanosaurus, is more similar to its later relatives and provides less insight into the early evolution of the group than the new find. Isanosaurus was discovered in Thailand in sediments 10 to 15 million years more recent than those surrounding the new South African sauropod. Four-foot's First Steps Antetonitrus (pronounced ant-ee-tone-ite-rus) helps cement a gap between smaller primitive two-legged dinosaurs previously thought to be related to the well-known four-footed long-necked herbivores like the brontosaur. The new fossil fills in the time gap between the two groups. Antetonitrus appears to retain some of the more primitive features of two-legged dinosaurs while possessing the more advanced body shape of sauropods. A key difference to later sauropods is in Antetonitrus' limbs. "The hand was not transformed into the tubular weight supporting device that it is in later sauropods, it had kept a…crude grasping [thumb] seen in earlier two-legged dinosaurs," said Yates, also noting that Antetonitrus' "hind feet were not quite the stumpy broad elephant-like feet of later sauropods. The toes were still quite long." "We now know [sauropods] were present in the early history of the dinosaurs. We just hadn't recognized them," he said. Yates and Kitching will publish their new description of the species in an upcoming print edition of London's Royal Society Journal Biology Letters. Kitching has built his reputation since the 1950s uncovering great quantities of Triassic and older Permian fossils in South Africa's Karoo region. Monumental Beasts While Antetonitrus was larger than any land animal living today and its contemporaries, it pales in comparison to the monumental dinosaurs that would follow millions of years later. Brachiosaur species from the Jurassic period (200 to 144 million years ago) ranged from 22 to 30 meters (72 to 98 feet) in length and weighed a whopping 30 to 80 tons (27 to 73 metric tons). Even larger dinosaurs followed in later periods until their extinction 65 million years ago. But the newly discovered species was the first dinosaur giant, said Michael Benton, a dinosaur expert at the University of Bristol in England who commended the find. "[Antetonitrus] is a quadruped because it has to be," said Benton. "At that size it couldn't continue as a biped." The new fossil shows that the four-footed dinosaurs evolved from two-footed ancestors earlier than thought and, surprisingly, retained some grasping function in their forelimbs, Benton said. "All later sauropods have [hands] designed solely to support their weight," he said. And that transition to four-feet allowed sauropods to attain great size, and reap the benefits in more ways than one. Huge animals are more challenging snacks for predators, rarely get cold, and are able to break down large quantities of otherwise low quality plant food, by slowly fermenting it in their massively elongated guts. Naming a new dinosaur is the "realization of a lifelong dream," said Yates. While ingenipes means massive paw, Antetonitrus comes from the Latin for before the thunder, and is fitting for an early ancestor of Brontosaurus—Greek for thunder lizard. More National Geographic News Stories on Dinosaurs: Dinosaur Cannibal: Fossil Evidence Found in Africa Bizarre Dinosaurs Shed Light on Adaptation Robots Designed to Show How Dinosaurs Moved Dino Dung: Paleontology's Next Frontier? Do They Really Look Like That? The Science of Dino Art Dinosaur Footprints: Tracks Tell Prehistoric Secrets Four-Winged Dinosaurs Found in China, Experts Announce Utah Dinos May Have Been Killed By Drought Cuban Dinosaur: First Confirmed Remains Discovered Dinosaur Cannibal?—Mystery in New Mexico Tetrapod Fossil Found—First Ever in Asia New Picture of Dinosaurs Emerging Fossil Implies Our Early Kin Lived in Trees, Study Says Weird Buck-Toothed Dinosaur Found Dinosaur Tracks Preserved on Scottish Island Dinosaur Tracks Shed Light on Sauropod Evolution Comets May Have Led to Birth and Death of Dinosaur Era Fossil of Dog-Size Horned Dinosaur Unearthed in China Tyrannosaurus rex Was a Slowpoke Researchers Rethink Dinosaur Die Off Scenario Researchers Melt Polar Dinosaur Mysteries Scientist's Finds Spur New Thinking on Dino Evolution Dino-Era Vomit Fossil Found in England Additional Dinosaur Resources from National Geographic: Paul Sereno: National Geographic Explorer-in-Residence and Dinosaur Hunter Dinorama Wanted: Albertosaurus Dinosaur Eggs Pterosaurs Destinations: Dinosaur National Monument RELATED LESSON PLANS Use this National Geographic News article in your classroom with these Xpeditions lesson plans and student activity: K-2: Dinosaur Bodies 3-5: How Do Scientists Find Dinosaur Fossils? 6-8: The Science of Digging Up Dinosaurs 9-12: The Evolution of Dinosaurs Over Geologic Time K-2: Those Fussy Dinosaurs! 9-12: Physical Characteristics of Places: The Fossil Record Activity: A Dinosaur's Neighborhood |
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