Before triceratops, there was this prickly fellow
Scientists in Alberta have identified a new type of horned dinosaur that looked like Triceratops but lived 15 million years earlier.
Called Xenoceratops foremostensis, it was a 2-ton vegetarian that flourished 80 million years ago, making it the oldest known large-bodied horned dinosaur to be found in Canada.
"This guy was the size of a large bull, with two big brow horns over its eyes and a big shield off the back of its skull," said Michael Ryan, head of vertebrate paleontology at the Cleveland Museum of Natural History and an author of a study describing the species in the current issue of The Canadian Journal of Earth Sciences.
"And it had a beak at the front of the mouth, very much like a turtle."
Fossils of Xenoceratops were first collected in 1958, but were left unidentified at the Canadian Museum of Nature in Ottawa.
Ryan and a co-author, David Evans of the Royal Ontario Museum and the University of Toronto, are working on a larger effort, the Southern Alberta Dinosaur Project, that has identified about 10 new dinosaurs, including Xenoceratops.
Most of the known dinosaurs from Alberta were found farther north, in Dinosaur Provincial Park and Drumheller. The dinosaurs to the south, like Xenoceratops, lived at least 15 million years earlier than those in the north, Ryan said.
"We're trying to find enough new dinosaurs further south to help us understand what led up to the extinction event," he added.
For maya, climate change may have been blessing and curse
The ancient Maya civilization may have risen — and then fallen — in response to climate change, scientists report after creating precise climate records going back 2,000 years.
The researchers, whose findings appear in the current issue of the journal Science, reconstructed rainfall patterns using cross-sections of stalagmites from a cave near the ancient city of Uxbenka, in what is now southern Belize.
First, they dated the samples with the technique called uranium-thorium dating; then, to generate a climate record, they measured oxygen isotopes, which are sensitive to rainfall.
The early classic Maya period — about A.D. 450 to 660 — "was remarkably wet," said an author of the study, Douglas Kennett, a geo-archaeologist at Penn State.
"There was a proliferation of population, an increase in agriculture and a rise in divine kings that became prominent leaders."
But then things dried up. The researchers compared the climate record with an existing "war index" — a log of hostile events based on how often certain keywords occurred in Maya inscriptions on stone monuments — and found a strong correlation between drought and warfare between cities.
"About A.D. 660, you get indications of some social stress that goes up in tandem with this drying period," Kennett said.
Maya cities were linked, but each operated with its own autonomous political structure.
When resources were strained, the groups may have turned against one another.
Over several hundred years, "the social fabric was eventually destabilized," Kennett said.
Most Maya cities collapsed between A.D. 800 and 900.
New York Times Service
