A reconstructed version of the new mammalian fossil is on...

A reconstructed version of the new mammalian fossil is on display at Stony Brook University Hospital on Nov. 5, 2014. Credit: Heather Walsh

The discovery of a prehistoric skull throws a wrench into theories about mammalian development and suggests furry creatures of considerable size roamed Earth alongside the dinosaurs, a Long Island scientist announced Wednesday.

David W. Krause, a professor of anatomical sciences, unveiled a model of the fossil during a lecture on his find Wednesday at Stony Brook University Hospital. Krause, who also is a paleontologist, said his newly identified creature looked like a giant groundhog.

"It has features that are both distinctive and downright bizarre," Krause said. "It has flanges on the side of its head and the brain case is oriented at a funny angle. Those are features we don't see in other Mesozoic animals." Flanges are bony structures that helped the herbivorous animal gnaw through jungle vegetation in what today is Madagascar.

"This animal was a chewing machine," Krause said. He and his colleagues reported on the giant rodentlike creature, christened Vintana sertichi, in Wednesday's journal Nature.

Unlike modern rodents, this creature weighed around 20 pounds and roamed Earth's Southern Hemisphere 70 million years ago. It measured about 24 inches, nose to rump.

John Flynn, an expert in fossil mammals at the American Museum of Natural History in Manhattan, called the find "fantastic" because of its preservation and relative completeness, compared with other Southern Hemisphere fossils. Flynn was not part of the research.

Yet as rodentlike as the fossil appears, it wasn't an early ancestor of modern mice or shrews but stands out as a unique creature. Its discovery, Krause said, "shakes up the early part of the mammalian family tree."

The fossil counteracts previous theories on mammalian evolution, Krause said, because of its size and presence in Madagascar. The Southern Hemisphere's early history hasn't been as well explored as its northern counterpart, he noted.

"It's huge, about twice the size of a modern groundhog and belongs to the group of mammals known as Gondwanatherians," Krause said of an extinct group of mammals that lived during the Cretaceous through Miocene periods.

Gondwana or Gondwanaland was the southernmost of Earth's two vast supercontinents 180 million years ago, the other was Laurasia.

Krause isn't the only Stony Brook anatomical scientist to make a key paleontological find this year. In July, assistant professor Alan Turner announced the discovery of a gliding forerunner to modern birds that he unearthed in China.

Vintana sertichi, however, was essentially an accidental discovery.

"In 2010 I sent a field crew to a remote area of Madagascar to find fish fossils," Krause said, adding that a graduate student returned with a huge piece of sandstone, which was examined via CT scan. "When we scanned it, we were absolutely stunned to see this mammalian fossil staring back at us."

With AP

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