SSS 2008-09-22（在线收听）

This is Scientific American's 60-Second Science. I'm Karen Hopkin. This will just take a minute.

Fingers are pretty nifty. They let you to grab a latte, type on a keyboard, even pull up your pants. But did you ever wonder: where do fingers come from? In the 1990s, scientists gave this problem a lot of thought. And they concluded that fingers were pretty much invented by the first tetrapods: that is, critters with four limbs. One reason they thought that is because a fossilized skeleton of an ancient fish didn’t appear to have any fingers. Or at least any distinct digits in its pectoral fin. But tetrapods, which evolved from fish, did.

Now scientists writing in the September 21st online issue of Nature say that that thinking was…a little fishy. Because they’ve unearthed evidence that suggests that that ancient fish did indeed have fingers in its fins. The researchers did a CT scan on a specimen about 380 million years old. And they found that the fish’s right fin, which was unusually well-preserved, does appear to have digitlike bones. The reason other researchers previously missed them, they think, is because in their samples the fingers were hidden behind marks left by the fish’s scales. So fish, too, seem to have incipient fingers. A finding we give two thumbs up.

Thanks for the minute for Scientific American's 60-Second Science. I'm Karen Hopkin.