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Huge nose on new dinosaur species may not have helped it smell

July 17, 2013|By Melissa Pandika
  • Paleontologists have discovered a strange new dinosaur -- a relative of Triceratops with a humongous honker. Nasutoceratops titusi, whose genus name means "big-nose horned face," roamed present-day Utah about 76 million years ago. This is an artist's rendition of Nasutoceratops.
Paleontologists have discovered a strange new dinosaur -- a relative of… (Lukas Panzarin )

Paleontologists have discovered a strange new dinosaur -- a relative of Triceratops with a humongous honker. Nasutoceratops titusi, whose genus name means “big-nose horned face,” roamed present-day Utah about 76 million years ago. The find sheds further light on the dinosaur communities that inhabited what’s now the western edge of North America.

Similar to its relative Triceratops, Nasutoceratops measured about 15 feet long and weighed roughly 2.5 tons. Its colossal 4.5-foot skull bore a single horn over the nose, along with a horn above each eye and an elongated, bony frill toward the rear. Its large, flat teeth were perfect for shearing plant matter.

But the dinosaur also possessed an array of unique features, according to a report published Wednesday in the Proceedings of the Royal Society B.

For one, the bony cavern housing Nasutoceratops’ nose was remarkably large compared with those of other horned dinosaurs. But that doesn’t necessarily mean the creature had a more refined sense of smell, since the olfactory receptors would have sat farther back in the skull, said Scott Sampson, a paleontologist at the Denver Museum of Nature & Science who co-wrote the study.

University of Utah paleontologist and study coauthor Mark Loewen said he suspected prospective mates found the oversized nose attractive, since the rapid change previously observed among related species is characteristic of sexual selection--when animals select for certain physical characteristics in choosing a mate. This selection might have then “fixed” the trait within the species over time.

Nasutoceratops’ horns, which measured 3.5 feet long, were about twice as long as those of its relatives. They were also curved and forward-facing instead of stubby and pointed upward. However, it probably used its horns for similar purposes — attracting mates and intimidating or combating members of the same sex, Loewen explained.

The new species also differed in its bony frill, which lacked the “bells and whistles”  of its relatives, such as horns or spikes, Sampson said. Rather, the frill was relatively unadorned, with a simple, scalloped edge, although it could have still served as a mating display. Sampson added that Nasutoceratops probably moved its head back and forth, similar to how the modern-day peacock shakes its plumage to and fro.

Paleontologists unearthed the Nasutoceratops skull and other bone fragments in Utah’s Grand Staircase-Escalante National Monument in 2006 while on an excavation to understand how Tyrannosaurus rex and Triceratops communities had formed. The region was once part of Laramidia, the westernmost island that formed when a shallow sea flooded central North America.

Study coauthor Eric Lund, a University of Utah graduate student at the time, spotted the bones protruding from the ground. For the next few weeks, he and the other team members worked on excavating the remains. After encasing the fossils in protective plaster, they hauled them onto a rescue board — the same used by paramedics — and transported them to Salt Lake City, where they used miniature jackhammers to chip away the plaster and remaining sediment, a process that took roughly three years.

“When we saw the curved horns we knew we had something pretty cool,” Loewen said. Later, when he and his colleagues exposed the no-frills frill at the back of the skull, they knew that they had found a “completely new” species.

To make sure, though, the team spent three more years traveling the world, comparing the fossils’ physical characteristics to all known plant-eating specimens, some housed as far away as Sweden and China. Their analysis revealed that the bizarre behemoth did indeed represent a new branch on the dinosaur family tree.

Nasutoceratops’ discovery also offered evidence of a larger divergence that separated the Laramidian dinosaurs into two distinct, distantly related communities.

Today, specimens from several species can be found in both Mexico and Canada. But fossil evidence suggests that species didn’t roam so widely in the Late Cretaceous period, about 100  million years ago.

Beginning in the 1960s, paleontologists began finding different types  of dinosaurs in northern Laramidia — near Alberta, Canada, and Montana, for example — and southern Laramidia — around Utah and Texas. The Nasutoceratops fossils add to the roster of species found in one area only.

Researchers have found this evidence of “dinosaur provincialism” puzzling.  Currently, five large mammal species — weighing about a ton or more — live on the African continent. But about 76 million years ago, at least 20 giant dinosaur species lived on a land mass one-quarter that size, Sampson said.

“How can you fit so many huge creatures on such a small chunk of real estate?” he said.

He pointed to food as a possible factor. Perhaps warmer temperatures yielded an abundant food supply, or being cold-blooded meant that dinosaurs didn’t have to eat as much.  (Cold-blooded animals don’t need to expend energy to maintain a high body temperature, unlike their warm-blooded counterparts.)

But why the northern and southern communities didn’t mingle remains a mystery. Loewen thinks they might have had different food preferences, favoring the plants in one region over the other. Alternately, a physical barrier might have separated the two communities.

“We’re still trying to figure that out,” he said.

The Nasutoceratops find “tells us we really don’t know much about dinosaurs,” Sampson said. “We’re just beginning to unravel the secrets of that world.”

Return to Science Now.

melissa.pandika@latimes.com

Twitter: @mmpandika


 

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