July 16, 2010

Ancient Marsupial Skulls Unearthed In Cave

Scientists have discovered a cave housing 15-million-year-old fossils of prehistoric marsupials in the Outback.

The researchers unearthed 26 skulls from an extinct, wombat-like marsupial called Nimbadon lavarackorum, which is an odd sheep sized creature with giant claws.  The findings were reported this week in the Journal of Vertebrate Paleontology.

"It's extraordinarily exciting for us," said University of New South Wales paleontologist Mike Archer, co-author of the article. "It's given us a window into the past of Australia that we simply didn't even have a pigeonhole into before. It's an extra insight into some of the strangest animals you could possibly imagine."

The scientists have been digging at the site since 1990 and discovered the first of the Nimbadon skulls in 1993.  They said they were amazed at how many fossils they found and how well preserved they were.

Paleontologist Karen Black, who led the research team, said that discovering such a large cluster suggests that the animals may have traveled in herds like modern-day kangaroos.

It remains a mystery how the animals ended up there.  One theory is that they accidentally plunged into the cave through an opening obscured by vegetation and either died from the fall, or became trapped and later perished.

The skulls included babies still in their mother's pouches, allowing the researchers to study how the animals developed.  The scientists found that bones at the front of the face developed quite quickly, which would have allowed the baby to suckle from its mother at an extremely young age.

Black told The Associated Press (AP) that those findings suggest the Nimbadon babies developed similarly to how kangaroos develop today.

The Nimbadon also has something in common with koalas.  Black said the fossils revealed the creatures had large claws, which may have been used to climb trees.

Paleontologist Liz Reed of Flinders University in South Australia said the discovery of the fossils is very significant.

"To find a complete specimen like that and so many from an age range is quite unique," Reed, who was not affiliated with the study, told AP. "It allows us to say something about behavior and growth and a whole bunch of things that we wouldn't normally be able to do."

Image credit: Karen Black


On the Net: