Dinosaur with 15 horns found on lost continent of Laramidia
Fossils were discovered in U.S.'s 'last great, largely unexplored dinosaur boneyards.'
Fri, Sep 24, 2010 at 11:27 AM
A bizarre dinosaur with 15 horns is one of two new close relatives of Triceratops that scientists unearthed in southern Utah from lands once part of a now-lost continent called Laramidia.
The dinosaur, named Kosmoceratops richardsoni, had a horn over its nose, one atop each eye, one at the tip of each cheekbone, and 10 across the rear margin of its bony frill. Its head is the most ornate of any dinosaur known.
The name comes from the Latin "kosmos" for ornate, the Greek "ceratops" meaning horned face, and the latter part honors Scott Richardson, the volunteer who discovered two skulls of this animal in 2007.
"Kosmoceratops is one of the most amazing animals known, with a huge skull decorated with an assortment of bony bells and whistles," said researcher Scott Sampson, a research curator at the Utah Museum of Natural History.
Kosmoceratops was perhaps 15 feet (5 meters) long and weighed about 5,500 pounds (2,500 kilograms) when alive.
Its larger relative, also newly discovered, is named Utahceratops gettyi – honoring Mike Getty, paleontology collections manager at the Utah Museum of Natural History, who discovered this behemoth in 2000. It possessed a large horn over the nose, and short, blunt eye horns that projected strongly to the side rather than upward, much more like the horns of modern bison than those of Triceratops and its other relatives, known as ceratopsians.
Utahceratops was roughly 18 to 22 feet (6 to 7 meters) long and about 6 feet (2 meters) tall at the shoulder and hips, and overall weighed about 6,600 to 8,800 pounds (3,000 to 4,000 kilograms).
Utahceratops possessed a skull about 7 feet (2.3 meters) long, prompting researcher Mark Loewen, a paleontologist at the Utah Museum of Natural History, to liken it to "a giant rhino with a ridiculously super-sized head."
Although scientists have speculated that the ornate horns and frills of ceratopsians might have helped fight off carnivores, for the newly discovered dinosaurs "most of these bizarre features would have made lousy weapons to fend off predators," Sampson said. "It's far more likely that they were used to intimidate or do battle with rivals of the same sex, as well as to attract individuals of the opposite sex."
Land of the lost
These new beasts were unearthed in Grand Staircase-Escalante National Monument in southern Utah. "Grand Staircase-Escalante National Monument is now one of the country's last great, largely unexplored dinosaur boneyards," Sampson said.
Back when these behemoths were alive roughly 76 million years ago, the area was part of the island continent of Laramidia, which was born when a warm, shallow sea dubbed the Western Interior Seaway flooded the central region of North America 95 million years ago. This split the eastern and western portions of the modern continent for 27 million years until sea levels fell again. Western North America formed a roughly Australia-sized continent called Laramidia, stretching from Mexico in the south to Alaska in the north, while Eastern North America was known as Appalachia.
Most known dinosaurs from Laramidia were concentrated in a narrow belt of plains sandwiched between the seaway to the east and mountains to the west. Utah was located in the southern part of the continent, and Kosmoceratops and Utahceratops lived in a swampy, subtropical environment about 60 miles (100 kilometers) from the seaway.
These new dinosaurs are part of a wave of discoveries made in the southern part of Laramidia that could help solve a mystery roughly a half-century old.
Starting about 50 year ago, paleontologists began noticing that although they found major groups of dinosaurs all throughout Laramidia, different species of these groups appeared in the north than in the south — for example, Alberta and Montana versus New Mexico and Texas. Such provincialism seemed odd, given the small size of the continent. For comparison, there are currently five rhino- to elephant-sized mammals on the entire continent of Africa, while there may have been more than two dozen giant dinosaurs living on Laramidia, a landmass about one-quarter that size.
Apparently, some kind of barrier existed near the latitude of northern Utah and Colorado that limited the exchange of dinosaur species north and south. Perhaps there were physical barriers such as mountains or rivers, "but we have no evidence of such then," Sampson said. "That means that perhaps these areas were separated by ecology, with different plants found in both regions, which in turn would spur different sets of herbivores to evolve and then different sets of carnivores."
Investigations into the roots of this provincialism have been severely limited by the dearth of dinosaurs found in the southern part of Laramidia compared with the north. Scientists are now overcoming this shortfall, unearthing more than a dozen species of dinosaurs in the last decade in Grand Staircase-Escalante National Monument.
"One reason that these dinosaurs weren't found before was the challenge that Grand Staircase-Escalante National Monument poses," Sampson said. "It's nearly 2 million acres of high desert, and it's so rugged that indigenous peoples to pioneers to people today usually go around it instead of trying to go into it."
Many places the researchers dug at were 25 miles (40 km) from the nearest paved roads. "We often had to hike up rugged terrain, bringing in not just food and water, but jackhammers and rock-saws, as well as plaster and burlap to wrap the fossils in big protective jackets that we would get helicopters to airlift," Sampson told LiveScience. "These relatively unexplored treasure troves were exciting places to be."
Too many giants?
In addition to Kosmoceratops and Utahceratops, scientists have unearthed a variety of other plant-eating dinosaurs in the national monument, including duck-billed hadrosaurs, such as Gryposaurus monumentensis, armored ankylosaurs, and dome-headed pachycephalosaurs. They have also dug up large and small carnivorous dinosaurs, from raptor-like predators, such as Hagryphus giganteu, to mega-sized tyrannosaurs — not T. rex, but its smaller relatives. These findings help confirm that dinosaurs living on Laramidia were divided into provinces.
Paleontologists have also found a variety of fossil plants, insect traces, clams, fishes, amphibians, lizards, turtles, crocodiles, and mammals, helping them picture this ancient ecosystem in its entirety.
The mystery of why these provinces occurred remains. There is also the enigma of how so many giant animals could live in such a relatively small area — perhaps food was abundant, or they needed to eat less than large herbivores do today.
"Now we get to try and put together the world of dinosaurs, to understand the ecosystems they lived in," Sampson said. "Their world was similar in many ways to our own, but in some ways was radically different, and we may have to rethink some of our basic assumptions of how such large-bodied animals lived."
Many more dinosaurs likely remain to be unearthed in southern Utah. "It's an exciting time to be a paleontologist," Sampson added. "With many new dinosaurs still discovered each year, we can be quite certain that plenty of surprises still await us out there."
The scientists detailed their findings online September 22 in the journal PLoS ONE.