Wednesday, September 23, 2009

Dinosaur Hunter

On the weekend I went to another Bookworm event, this time a talk presented by well-known paleontologist Xu Xing (徐星), a professor of Vertebrate Paleontology and Paleoanthropology at the Chinese Academy of Sciences.
He has named over 30 dinosaurs in his career so far and published many papers in Nature magazine. One can tell from his presentation how passionate this 40-year-old is about dinosaurs and educating people about these creatures from hundreds of millions of years ago.
A lot has changed about what we know about the dinosaur world since I went to school eons ago. We used to think of them as mammoth creatures, but now we know there was a whole range of sizes.
Xu's work mainly focuses on finding more evidence to prove that birds came from dinosaurs. He says they have proof as all birds have wish bones, and as it turns out, dinosaurs do too -- even meat-eating ones. He has also found fossils showing dinosaurs in a sleeping position that are similar to birds.
However, most of the dinosaurs that were found had scaly skin and no evidence of feathers.
But in 1996, they were able to find one in Liaoning Province. They applied for permission to dig in the area, but when they got approval from the provincial government, it was in the winter time, Xu explained, showing us a picture of them digging with snow that lightly covered the ground. They dug for 30 days but found nothing. But on the last day, Xu, who was staying in a farmer's home, met with a farmer who showed him some fragments, and indeed one of the fossils showed imprints of feathers.
Xu and his team were all excited and applied to dig there again the following year, this time in the summer. They planned to be there for 70 days, but little did they know it was the rainy season, making it very difficult for them to do their work. Again nothing much turned up. Xu had to leave two days earlier to go back to Beijing. And on the last day of the dig, one of his assistants called him to say they had found a fossil of a bird-like creature that had sharp teeth.
Their theory is that feathers evolved from being like a strand of hair, into a kind of leafy fringe and then becoming like the feathers we know today.
There are also theories on how early dinosaurs flew. One is that they started from the ground by having a running head start before taking off, while the other is that they lived in trees and took off from the branches like birds today. However, scientists have yet to find evidence that dinosaurs lived in trees.

Xu and his team also named the Microraptor - a dinosaur that had four wings on its arms and legs. They also found a giant dinosaur pictured above that they called a Jinzhousaurus, a herbivore, after the place it was found. And they discovered the Gigantoraptor, a giant dinosaur with feathered wings that looks like a precursor to the ostrich.

He explained that there are many fossils under the ground, but those covered beneath vegetation are hard to find. That's why he and his team go to quarries to find fossils, mostly in the Gobi Desert, Erlian Gobi in Inner Mongolia, and Xinjiang. The fossils are found in slate, which is made of layers of rock.

China Central Television (CCTV) and NHK (Japan Broadcasting Corp) have both filmed Xu and his team, and each time they resulted in finding more dinosaur fossils.

CCTV wanted to do a documentary so Xu invited them along. After the interviews, they wanted to film them pretending to dig. So his assistant threw her hat into the air and where it landed they started digging. About half an hour later they found a new dinosaur.

Then with NHK, the crew also wanted to film them digging. One of Xu's assistants remembered there was something nearby and so they went there and there was a kind of bone fossil sticking out from a cave-like earth. They dusted it off and they surmised the bone was a kind of dinosaur, but not one that would help them futher prove that birds came from dinosaurs. But the more they uncovered it, the more they realized it was not the particular dinosaur but another one that would have been over 30 metres long.

Xu recalled he also invited a writer from National Geographic to come on a dig with them for a story. They didn't find much, but the American writer showed him some fossil fragments and Xu immediately dismissed them, saying they were not what they were looking for. Also, as Xu has been lucky finding many fossils of dinosaurs pretty much intact, he was hoping for better specimens.

However, they did bring these fragments back to the lab and later realized that it was a primitive crocodile. It has a similar skull to today's crocodiles, but had slender legs so it was very agile unlike its lumbering predecessors.

On the topic of evolution, Xu praised Charles Darwin for his theory of evolution, saying that no other person has come up with such a revolutionary concept that still basically applies to today.

While Xu has found many fossils that are strong evidence to prove that birds came from dinosaurs, he has not found all the pieces to the puzzle. But his case is getting stronger and it will only be a matter of time before most of the pieces will be discovered.

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