Reading the Bones

Jun 20, 11:19 AM

Current Headlines: By RITA SHERROW

Scientists discover skeleton of Australia's marsupial lion

Australian paleontologist John Long has been dusting off bones ever since he was a kid.

But his eureka moment came in 2002.

That was when he opened an unexpected e-mail that contained a photo of a pristine skeleton of a Thylacoleo carnifex -- Australia's own marsupial lion (a "lion" with a pouch). It was "a bit like finding the Holy Grail of Australian vertebrate paleontology," Long said in an ABC "Science" interview in 2002.

Long's expedition to the site -- a series of three caves in the vast Nullarbor Plain in Western Australia -- is featured in the "Nova" documentary "Bone Diggers," airing Tuesday on PBS.

Seeing the skeleton in person was "one of the most exciting paleontological moments of my life," said Long, head of sciences for the Museum Victoria.

An estimated half a million years old, the skeleton was in pristine condition, neither fossilized nor covered with debris, he said in a recent phone interview from his office in Melbourne.

Traveling to the skeleton's final resting place involved taking a circuitous route to throw off any would-be fossil poachers and splitting up so no tracks would give away its position. Then the team had to drop more than 65 feet into the blackness of a small cave, first spotted by an explorer in an ultralight aircraft.

"It was breathtakingly scary to lower yourself down a rope in a hole with blasting air all around," said Long. "The caves breathe because of the differential of air temperature above and below the ground. You lower yourself down into the lowest part of the cave, crawl around and there was a whole, complete skeleton of one of the most elusive fossils. The Holy Grail of Australia was to find the first complete skelton. Because the caves breathe, no dust or dirt had settled on it."

Long's expedition, the first of three over subsequent years, was possible because of the cavers who originally found Thylacoleo. The cavers knew enough to take pictures of the skeleton but not disturb it.

"The cavers were very clever," said Long. "They were like a model for people discovering fossils. They didn't touch it or go near it, but they knew it was something of great scientific importance. The expeditions involved bringing them back to the site so we could all work together. It was a model for how musuems and communities can work together."

What the the cavers discovered were the bones of a tree-dwelling creature weighing upwards of 200 pounds, an estimated 6 feet long, with a stout tail for balance (like a kangaroo), thumbs with huge slashing claws for disemboweling prey, long back teeth for shearing off flesh, and two prominent incisors, shaped into a structure similar to a parrot's beak. It is this beak-teeth arrangement that is a characteristic of marsupials such as kangaroos, possums, koalas and wombats, said Long.

"It had these distinctly large teeth," he said. "If you've ever seen one, you will never forget it."

The skeleton was dated to 400,000 to 800,000 years old. It probably died where it was found, according to the film.

To get it safely to the museum was a feat for Long and his co- workers, who spent five tedious days painting each bone with glue to strengthen it from the inside out before numbering and wrapping each piece for transport. Unlike hard, fossilized bone, the skeletal parts could have disintegrated to dust if moved without proper preparation.

"It was quite an amazing specimen," said Long, who has written more than 200 scientific papers and more than 60 popular science articles. "We thought we have to take this one very carefully because it was a once in a lifetime find. It was incredibly fragile."

The same cavern -- the size of a football stadium -- also contained a treasure trove of other astonishing fossils. In addition to 11 incomplete skeletons of Thylcoleo, scientists also have identified more than 60 species of mammals, reptiles and birds, including eight new species of kangaroos (one with horned or bony protusions over its eyes), giant kangaroos over nine feet tall and wombats the size of ponies.

There is an on-going project studying the bones in the sediment, which scientists hope will reveal a history of the Nullarbor Plain and its animals, Long said.

Rita Sherrow 581-8360

rita.sherrow@tulsaworld.com

Nova: Bone Diggers

"Nova: Bone Diggers"

When: 7 p.m. Tuesday

Where: PBS, channel 11

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