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Utah's dino hotbed yields 4 skulls of new sauropod

PROVO — Utah's newest dinosaur is getting a lot of attention for leaving behind what few of its relatives did — its skull.

A team of paleontologists hit the post-Jurassic jackpot with the discovery of four rare skulls within Dinosaur National Monument — so rare that park paleontologist Dan Chure said they have the only complete Cretaceous sauropod skull in the Western Hemisphere.

"When we started digging there … I don't think anyone believed we'd find such spectacular skull material," Chure said. "You always hope you're going to find something like this, but the reality is that so few of them have good skull material preserved that you could go your entire scientific career and never find anything like this."

The new 105 million-year-old plant-eating dinosaur has been named Abydosaurus mcintoshi, and is part of the sauropod family, which also claims the familiar brachiosaurus.

Finding sauropod skulls is such a big deal, says BYU geology professor and paleontologist Brooks Britt, because only eight of the 120 known varieties of sauropods have a complete skeletal reconstruction that includes a skull.

Most skulls, which were composed of thin, fragile bones and soft tissue, quickly decomposed after the dino died.

So it's amazing to find one skull, let alone several, within a designated dinosaur monument, Britt said.

"(They were found) within a quarter of a mile from the visitors center," he said. "(Dinosaur National Monument) is one of the most famous dinosaur localities in the world and has been producing dinosaurs for over 100 years. So here we are, over 100 years later, finding new dinosaurs in the Mecca for dinosaur paleontology."

The skulls were found in the Cedar Mountain Formation, not previously known for its fossil deposits, Chure said.

However, in the mid-1980s, several large bones were collected because they were exposed and being damaged by erosion. Researchers noticed additional bones underneath but had to finish other projects before they could dig there.

The first complete skull was discovered there in the late 1990s, and as Britt and several BYU students began digging their way through an excavated 6,000-pound block of stone in 2004, they unearthed three more skulls, including one fully intact.

However, nothing in paleontology happens overnight, Britt quipped, which explains why it took several years to get the bones out of the rocks and properly identified.

They will be returning this summer to excavate additional Abydosaurus bones.

Their research will be published in the journal Naturwissenshaften, The Science of Nature, accessible on Wednesday at www.springerlink.com/content/100479/.

Other co-authors include University of Michigan researchers John Whitlock and Jeffrey Wilson.

"I just can't convey how exciting it is to work with such well-preserved and rare materials," Britt said. "To hold these in your hands is just amazing."

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The Abydosaurus mcintoshi, at 105 million years old, is clearly related to its brachiosaurus ancestors of 150 million years ago, but it has some interesting differences, Britt explains.

Older sauropods' teeth resembled C or D-batteries — broad, peg-shaped chompers.

However, the Abydosaurus' teeth look more like short AAA-batteries, and because the teeth are smaller, its mouth has more teeth than its predecessors.

"It's just a strange thing about sauropods," Britt said, "none could chew their foods, they just bit it off and swallowed it. The point is, they've made themselves more efficient at biting."

The additional teeth also meant more enamel, which could keep the teeth from wearing out as quickly.

e-mail: sisraelsen@desnews.com