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First Dinosaur Tracks Found on Arabian Peninsula

Anne Casselman
for National Geographic News
May 20, 2008
 
More than a hundred dinosaur footprints have been found on the Arabian Peninsula, the first time that tracks have been unearthed in the region, a new study says.

The 150-million-year-old tracks were made by ornithopods and sauropods—large two- and four-legged plant-eaters, respectively—in modern-day Yemen.

"The first day in the field we had a herd of eleven sauropods and over a hundred prints," said lead author Anne Schulp, a paleontologist at the Natuurhistorisch Museum Maastricht in the Netherlands.

"It's providing the first data point, at least in terms of trackways from this part of the world," she said.

The tracks were first discovered by Mohammed Al-Daheri, a Yemeni journalist, about 31 miles (50 kilometers) north of Yemen's capital, Şan'ā'. (See a Yemen map.)

The journalist alerted Mohammed Al-Wosabi, a paleontologist at Şan'ā' University. Al-Wosabi contacted colleagues abroad, including Schulp, who visited the region in December 2006.

(See a photo of newfound dino tracks made by a meat-eating dinosaur.)

Leisurely Stroll

The footprints are a good example of herding behavior along a coastal mudflat in the late Jurassic period, which lasted from about 200 million to 150 million years ago, experts say.

The paleontologists were also able to infer the size, age, and speed of the sauropods based on their prints.

"We've got young dinosaurs and old ones—[or] at least small ones and big ones—in the same herd," Schulp said.

"The nice thing is they're all traveling together at the same speed"—something like a leisurely stroll, he added.

(Read: "Dinosaur Tracks Shed Light on Sauropod Evolution" [May 30, 2002].)

Martin Lockley, curator and director of the University of Colorado, Denver's Fossil Footprint Collection, was also not involved with the research.

"Tracks are a sort of snapshot—almost like a movie of a living animal—whereas bones tell you about the dead ones," Lockley said.

The find may also "spark some ecological debate," Lockley said, since "there's conventional wisdom that the two types of herbivorous dinosaurs—the ornithopods and sauropods—do not commonly co-occur or co-exist together," he said.

"My guess is that this is opening up a new frontier."

The study appears in this week's issue of the journal PLoS ONE.

Changing Assumptions?

Ornithopods are thought to have grown in size and number in the Cretaceous period, which followed the Jurassic and lasted until about 65 million years ago. (Test your dino IQ.)

But the large Yemeni footprints suggest instead that beefier ornithopods were stomping around earlier than previously believed.

"It's a pretty large one for late Jurassic standards," lead author Schulp said, "and it tells us right now that big ornithopod dinosaurs maybe appeared a little bit earlier than was assumed so far."

Nancy Stevens, a paleontologist at Ohio University in Athens, was a co-author on the study.

"This find is encouraging," she wrote in an email, "in that it represents what we hope is the first of many discoveries from this part of the Arabian Peninsula."
 

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