Thanks to Eric Klaver for the link.

Reposted from:
http://www.cbc.ca/technology/story/2008/02/13/science-bat-flying.html

ROM researcher helps uncover the earliest fossil yet of a prehistoric bat

A rare fossil of a prehistoric bat provides the first evidence that the tiny mammals could fly before they developed the ability to use sound to navigate and locate prey at night.

The discovery of the most primitive bat ever found answers a long-standing question about which distinct ability bats evolved first: flying or echolocation, the ability to emit high-pitched sounds and then interpret the sounds that bounce back to find objects or prey.

It's been a difficult question to answer for years because of the scarcity of fossil evidence, said Kevin Seymour, the assistant curator for vertebrate paleontology at the Royal Ontario Museum and one of the authors of a study on the find to be published Thursday in the journal Nature.

"Bats have been a real problem for evolutionary biologists because all the bat fossils we've found look like bats," Seymour told CBCNews.ca. "Up until now, the question of which ability came first has involved a lot of hand-waving, but we've had no data to prove either theory," he said.

"This is the first evidence of an ancestor with only some of the features."

The fossil, found in Wyoming, shows the tiny mammal that lived about 25.5 million years ago possessed many of the features found in bats, including skeletal features that suggested it could fly.

It also had claws on all of its fingers instead of just one or two fingers, suggesting it was capable of climbing and hanging from branches as a tree sloth might.

But an examination of its skull revealed that the shape of the bat's ear would not have supported echolocation, said Seymour.

Two fossils discovered

Getting an intact sample of the fossil was the first challenge for the researchers, said Seymour. There were actually two fossils of the bat, known now by its official name Onychonycteridae finneyi. The bats name honours the commercial collector, Bonnie Finney, who first found the fossil in 2003.

But that fossil had a crack in the back of its skull, which complicated the research into its ability to echolocate, said Seymour.

When a second fossil emerged from the same fossil find, Seymour and the ROM arranged to purchase the specimen in 2004 and bring it to the museum for preparation and examination.

That's where noted bat expert and lead author of the Nature paper Nancy Simmons came in, said Seymour. Simmons, the chair of the vertebrate zoology division at the American Museum of Natural History in New York, was able to assess the fossil in relation to other bat finds.

Two other researchers, Gregg Gunnell with the University of Michigan and Jorg Habersetzer with the Forschunginstitut Senkenberg, have since taken the second fossil find to Germany to run additional tests and see if they can create a three-dimensional picture of the bat's skull to learn more about features such as its eye sockets — which could provide insight into whether the early bat was a night-flyer like its modern relative, said Seymour.

Once the fossil has been examined thoroughly, it will return to the ROM in Toronto, said Seymour. But a cast of the first fossil is already on exhibit at the museum, he said, although right now it is simply labelled as "unidentified bat."

"I've got one spare label holder and a new label with the bat's name on it all ready," he said. "Thursday morning I'm going to change the name myself before our doors open."