New massive dino species dispels previous assumptions about sauropodomorphs

Thursday, January 22, 2009

Researchers digging in Antarctica have stumbled upon a new giant, plant-eating dinosaur that dates back to the Early Jurassic period, about 190 million years ago.

Named Glacialisaurus hammeri, the dino is a primitive sauropodomorph - a group of dinosaurs that produced the largest animals to ever walk the earth, including the long-necked herbivores, Diplodocus and Apatosaurus.

The find helps quench two aspects of the debate involving the evolutionary development of these giants: It tells palaeontologists more about where they lived and who they shared their world with.

"They help to establish that primitive sauropodomorph dinosaurs were more broadly distributed than previously thought, and that they coexisted with their cousins, the true sauropods," says Nathan Smith, a graduate student at The Field Museum. (Sauropods are another order of the sauropodomorpha.)

These dinos were widely distributed in the Early Jurassic, appearing not only in China, South Africa, South America and North America, but also in Antarctica.

"This was probably due to the fact that major connections between the continents still existed at that time, and because climates were more equitable across latitudes than they are today," Smith said.

The recent discovery of a possible sauropod from the same region that dating back to roughly the same period lends additional credence to the theory that Glaci coexisted with sauropods.

All that remains of the dino today are a partial foot, leg and ankle bones, but these are enough to tell scientists how big the creature was: About 20 to 25 feet long and weighing roughly 4 to 6 tonnes.

Scientists discovered Glaci's remains on Mt. Kirkpatrick, near Beardmore Glacier, at an elevation of 13,000 feet.

"The fossils were painstakingly removed from the ice and rock using jackhammers, rock saws and chisels under extremely difficult conditions over the course of two field seasons," says Smith.

The findings appear in the online edition of Acta Palaeontological Poiloncica.


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