Scientists put together a virtual model of an extinct lemur, large as a big baboon

Washington, July 29 : Researchers from Penn State University have used computed tomography (CT) technology to virtually glue newly-discovered skull fragments of a rare extinct lemur back into its partial skull, which reveals that it was as large as a big baboon.

Alan Walker, Evan Pugh Professor of Anthropology and Biology at Penn State, and Research Associate in Anthropology Timothy Ryan, led the research.

The different fragments of this lemur's skull are separated by thousands of miles, with the partial skull in Vienna and the pieces of frontal bone in the US.

The original specimens of Hadropithecus stenognathus were found in Andrahomana Cave in Madagascar by a professional fossil-collector, Franz Sikora, in 1899.

He sent a jaw and the partial skull to Ludwig Lorenz von Liburnau in Vienna, who published a paper in 1902 describing the skull and jaw as the remains of a new species.

In 2000, Natalie Vasey, presently an associate professor of anthropology at Portland State University - initiated a project to return to Andrahomana Cave in hopes of finding new specimens.

In 2003, Vasey, along with her team, excavated new cranial fragments and new limb bones of the elusive extinct lemur.

The fossilized pieces found in 2003 were sent to Penn State, where Walker and Ryan CT scanned them at the Penn State Center for Quantitative Imaging.

"From the moment we combined the two datasets, it was obvious that the fossils all belonged to the same individual," said Ryan.

"Because the newly-discovered fragments fit into the skull so cleanly, we decided to attempt a more thorough virtual reconstruction, filling in other missing pieces using the CT data or making mirror images of undamaged sections to restore damaged ones," he added.

The result was a beautiful image and three-dimensional print of the skull of the extinct lemur species.

The digitally reunited remains offered new insights about Hadropithecus.

For the first time, its cranial capacity (115 ml.) has been measured accurately. Because the excavators also uncovered many limb and trunk bones of the same individual lemur, the team could estimate its body size reliably.

Surprinsingly, Hadropithecus was as big as a large male baboon and had a relative brain size as large as that of some large monkeys.

In fact, the extinct lemur had one of the largest brains relative to its body size of any known prosimian (a group comprised of lorises, lemurs, bushbabies, and other similar animals).

The skull shape of Hadropithecus is unusual. Its skull vault sports a large, bony crest - similar to that seen on gorillas - for the attachment of powerful chewing muscles. ith big chewing muscles, a deep jaw, and a flat face, the skull of Hadropithecus seems mechanically suited to eating hard foods, such as seeds or nuts.

ANI