The peculiar dinosaurs of Laramidia: weird horns and more
The discovery of two new dinosaur species in the American West – which, 76 million years ago, was part of a continent called Laramidia – has scientists thinking about odd horns and why certain species didn't appear to spread out across all Laramidia.
Two new species of horned dinosaurs from the vanished continent of Laramidia – now western North American – are creating a buzz.Skip to next paragraph
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The creatures' arrangement of horns are unique among the broader group of dinosaurs they belong to, a group that includes animals such as Triceratops.
Moreover, the find appears to lends support to a contentious notion that dinosaurs were quite provincial on Laramidia. The same broad groups of large dinosaurs were present along the north-south reach of the narrow continent, but the species within each broad group differed north and south.
This contrasts with the appearance of large animals in the fossil record from more-recent times. During the last ice age, for example, one could hop into a hypothetical Land Rover, drive from the east coast to the west coast, marvel at the mammoths, mastodons, and giant sloths along the way, and each is "pretty much the same species from the Atlantic coast to the La Brea tar pits," says Thomas Holtz Jr., a paleontologist at the University of Maryland in College Park.
Horns: 'lousy weapons,' but stylish
One of the new dinosaurs, dubbed Utahceratops gettyi, not only sported a sizable horn on its nose. It also sprouted small horns protruding from its skull over each eye. Researches estimate that the beast stood about six feet tall at the shoulders, spanned up to 22 feet from nose to tail, and tipped the scales at about 2.5 tons.
Find No. 2, named Kosmoceratops richardsoni, sports a more-bizarre set of horns – 15 in all – that include a long nose horn, eye horns much longer than Utahceratops's, and another 12 along the bony, fan-like "frill" at the back of its skull.
Both animals lived some 76 million years ago, estimates the research team reporting the results this week in the on-line journal PLoS One, published by the Public Library of Science.
The finds come from the Grand Staircase-Escalante National Monument, a rugged patch of southern Utah that represents "one of the country's last great, largely unexplored dinosaur bone yards," says Scott Sampson, a curator at the Utah Museum of Natural History in Salt Lake City, who led the effort.
Between 95 and 68 million years ago, western North America formed a mini-continent, separated from the rest of what was to become North America by a shallow sea that stretched the from Arctic Ocean south to the Caribbean. Mountains dominated much of the continent. But the east coast sported a broad coastal plain where dinosaurs thrived in the warm, humid climate that dominated the planet.