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Dinosaurs for Thanksgiving dinner

The turkey on your Thanksgiving table is a dinosaur!

Yesterday, for Thanksgiving, my family ate a 20 pound dinosaur. Actually, before it was skinned, with feet and head and innards, it probably weighed more like 25 pounds. Meleagris gallopavo, biologists call it. It tasted good, for dinosaur.

Used to be, when I was a kid, my mother served turkey for Thanksgiving. "The bird," we called it. No longer. Birds are not what they seem, it seems. The beautiful cardinal flitting around your yard, flocks of ducks quacking their way south on their fall migration, the delicious turkey gracing our dinner table on holidays -- science now tells us they're dinosaurs!

I teach my college students that the dinosaurs all went extinct 65 million years ago , when a giant comet impacted earth near Yucatan (the part of Mexico that juts up into the Gulf of Mexico), ejecting so much debris into the atmosphere that light was blocked from reaching the ground. Its easy to see why the dinosaurs didn't make it through those terrible times. Imagine how long you would survive, living in perpetual pitch blackness at below-freezing temperatures without electricity. For just one "for instance," what would you drink?

It appears I have been wrong. One kind of dinosaur did survive. We call them birds.

The idea that birds are the direct descendants of dinosaurs is not a new one. One of the first scientists to study dinosaurs, Thomas Huxley, argued in 1878 that the skeletons of dinosaurs had many distinctive features shared with birds. They both have the little toe turned backwards, for example.

The idea fell into disrepute in 1926 when a respected Danish paleontologist named Heilmann pointed out that in birds the collar bones, called clavicles, are fused together to form the "wishbone" which braces the shoulder against the stresses of flapping the wings. Can't fly without one. The problem is that dinosaurs have no clavicle, although earlier reptiles did. Heilmann concluded that dinosaurs must have evolved from these earlier reptiles.

There the matter stood, with dinosaurs the brothers of birds rather than their ancestors, until 1964. Then the great Yale paleontologist John Ostrom discovered the first velociraptor-type dinosaurs. Looking at them, he saw something you or I would miss, but it shouted out volumes to him. The wrist of the velociraptor dinosaur had a swivel joint, swinging on a curved bone that allowed precisely controlled flexing movement -- just the sort of wrist a bird has!

Ostrom marshalled evidence over the next nine years, and then published a forceful argument that Archaeopteryx, the first bird, was virtually indistinguishable from fleet two-legged predatory dinosaurs known collectively as theropods. Marshalling a mountain of evidence, he convinced all but a recalcatrant few that birds are in fact a kind of dinosaur.

There were a few holdout, notably ornithologist Alan Feduccia, who were not comfortable with the idea. Birds, after all, have feathers. What about the feathers!

A series of remarkable fossils recently unearthed in fine clay deposits in China have settled the argument once and for all. Fine clay preserves soft tissues, and in these fossils the soft tissues provide crutial information. The first of these fossils, found in 1996, riveted the world of people who worry about things like dinosaurs. It was a dinosaur with feathers.

Called Sinornithosaurus (Latin for "China bird dinosaur"), the fossil was about a foot long, the size of a falcon. It had the distinctive tail of a therapod dinosaur -- and a body that appeared to be covered with a downy coat of simple feathers!

Any thought that perhaps these simple down feathers weren't REAL feathers was laid to rest the following year, with the discovery of a second feathered dinosaur. Beipiaosaurus is seven feet long with two-inch long feathers covering its body. No wings, though.... a faint hope for those holding out against the birdosaur onslaught.

That hope was dashed last month with the report of yet another feathered Chinese dinosaur, Archaeoraptor. This one has wings!

120 million years old, Archaeoraptor has a breast bone and wishbone similar to modern birds. Its hands have been modified to form part of the wing, just as in birds. It has a full set of feathers and a long tail to provide stability in flight. There is little doubt it could fly.

The new species has been placed in the family of dinosaurs called dromeosaurs, to which velociraptor and Tyrannosaurus rex belonged. Perhaps if Montana had the fine clays that in China have preserved fragile feathers, we would see T. rex in a different, more feathery light!

The most astonishing thing to me, though, the fact which haunted me all through Thanksgiving dinner, is the size of the new birdosaur. Archaeoraptor is the size of a turkey.

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