Sunday, February 21, 2010
N.M. Tyrannosaur Is Officially Dubbed Bistahieversor sealeyi
By John Fleck
Copyright © 2010 Albuquerque Journal
Journal Staff Writer
It took 74 million years, but the sharp-toothed, flesh-tearing dinosaur dubbed "Bisti Beast" finally has a real name.
But it might want to stick with the nickname.
In the January issue of the Journal of Vertebrate Paleontology, scientists formally bestowed the name Bistahieversor sealeyi on the dinosaur, a relative of Tyrannosaurus rex discovered 13 years ago in the wilderness of northwest New Mexico.
It was the most fearsome killer of the jungle it inhabited, said Tom Williamson, curator of paleontology at the Museum of Natural History and one of the scientists responsible for giving Bisti Beast its formal name.
The novelty of a new species of tyrannosaur, meat-eating monsters that dominated their world, makes the creature a prized attraction at the New Mexico Museum of Natural History and Science, where the beast's skull is now on display.
Its connection to T. rex, the most famous of dinosaurs, only adds to the marketing appeal.
But for science, Bisti Beast's real importance is the light it sheds on the complex evolution of meat-eating dinosaurs at an important time in their history, a subject that is still something of a mystery, said Randy Irmis, a curator at the Utah Museum of Natural History and professor at the University of Utah.
The new name, Bistahieversor sealeyi, comes from the place the dinosaur was discovered and the person who found it.
Museum of Natural History volunteer Paul Sealey was on a fossil-hunting trip when he spotted a bit of fossilized bone sticking out of a rock on federal land in the Bisti/De-Na-Zin Wilderness Area south of Farmington.
Only a bit of bone was sticking out of the rock, but museum scientists could tell it was a potentially important find, and a team of scientists and volunteers returned numerous times over the summer to dig out the 4-by-15 foot block of stone that held the dinosaur's bones.
The fieldwork culminated with a ride out of the wilderness for Bisti Beast's bones aboard a New Mexico National Guard helicopter.
A new species of dinosaur is always cause for attention, but Bisti Beast is especially valuable because of the detail it helps to provide about the complex relationship among dinosaurs alive at the time it lived, Irmis said in a telephone interview.
Across what is now North America, a number of species similar to Bisti Beast lived at the same time, each confined to a separate range, each the dominant predator at the top of the food chain, Irmis explained.
While Williamson and his colleagues were working on Bisti Beast, for example, Irmis and his colleagues have been studying a different species that lived simultaneously in what is now southern Utah.
A similar pattern is found in fossil beds from that time period across North America, Irmis explained. Each region has its own unique tyrannosaur, slightly different from the others.
Williamson and colleague Thomas Carr of Carthage College knew the Bisti Beast was unique because of a large, bony protuberance on its skull that no other known dinosaur has.
"If you had just this bone," Williamson said, pointing to the piece of the skull that contained the protuberance, "you could identify this dinosaur."
The question now is why each region had a different tyrannosaur. One possible explanation is that there were physical barriers, such as mountain ranges or seas, separating the regions, but Irmis said there is no evidence for that.
Another possibility is climate: different climates in different parts of the continent favored different creatures. That is the hypothesis Irmis is now looking at, but he admits he does not yet know if it is right.
"I don't think we have a great answer yet," Irmis said.