Fossil feud.

Scrambled dino eggs for breakfast? Feeding bread crumbs to dinos in your neighborhood park? Seeing dinos nest and chirp outside your bedroom window? Jurassic Park let loose??? Well, maybe. Paleontologists (fossil scientists) claim dinosaurs never really went extinct 65 million years ago--they're alive and feathered today ... as birds!

Could birds really be modern-day dinosaurs? A hard-boiled dispute has had paleontologists and a few ornithologists (bird scientists) squawking at each other for more than a century. On one hand, paleontologists insist that birds are not merely descendants of dinos--they are actual living dinosaurs. "Birds are a kind of theropod dinosaur, two-legged meat-eating dinosaurs," says paleontologist Mark Norell at the American Museum of Natural History (AMNH) in New York City.

Nonsense, say some ornithologists. "Paleontologists don't have any piece of evidence that remotely resembles a common dino-bird ancestor," says ornithologist Alan Feduccia at the University of North Carolina.

New evidence may make Feduccia and fellow ornithologists eat crow. Chinese paleontologists have recently discovered new dino fossils--with the clear imprint of feathers! This could be the strongest proof yet that birds are living dinos--though it's hard to imagine the ferocious raptors in Jurassic Park and Lost World shaking fluffy little feathers. Or is it?

"The new finding in China suggests that tyrannosaurs and velociraptors at least had a fluffy body covering, if not true feathers," Norell says.

FOR THE BIRDS

Of all living creatures on Earth, only birds sport feathers. But the feathered fossils uncovered in China's Liaoning Province indicate that bird-like dinos had feathers, too. Careful examination of the creatures' skeletal structure reveals that the fossilized animals are most closely related to theropod dinosaurs.

Scientists have named the turkey-size dinosaurs caudipteryx (pronounced cow-DIP-tuh-riks) and protarchaeopteryx (pro-tar-kee-UP-tuh-riks). They lived more than 120 million years ago. Feathers covered most of the caudipteryx's body, including its arms and tail. Paleontologists think the caudipteryx, whose name means "tail feathers," may have fanned out the large feathery plumes on its tail much like a peacock.

The protarchaeopteryx also displayed feathers on its tail, some of them about 15 to 20 cm (6 to 8 in.) long. Even though a dinosaur, the protarchaeopteryx ("first ancient wing") looked like a primitive archaeopteryx--the earliest known bird, which lived about 150 million years ago.

But neither feathered dinosaur could fly, says AMNH paleontologist Luis Chiappe. They were similar to feathered birds today that can't get off the ground, like ostriches and kiwis. "The proportion of the wing to the body and size of the feathers are too small," he explains. Well, if dinos didn't use feathers to soar into the air, why have feathers in the first place?

FEATHERED FRIENDS

Some scientists maintain that birds evolved feathers strictly for flight. But Chiappe disagrees: "Even though feathers are very important for flight now, in the beginning they had nothing to do with it." Instead, he explains, dinos evolved feathers to regulate their body temperatures and keep them insulated against cold. Maybe dinos even shook a tail feather or two to attract mates.

Regardless of feathers' functions, finding them on dinos is for scientists like finding the goose that laid the golden egg. That's because soft, delicate feathers decay much faster than hard bones, so they're less likely to form fossils--remains of ancient plants or animals usually preserved in rock. For fossilized feather impressions to form, a feather must be buried in sediments made of very fine grains that help preserve a feather's minute details and keep out decay-promoting oxygen. As a result, very few fossil-hunting grounds have yielded feathered fossils.

The Chinese discovery would seem to cinch the dino-bird debate. So, why are some scientists still pecking away at the evidence? See "Ruffled Feathers" (right) for more on bird scientists' eye view.

WEB SITES:

To find out more about the dino-bird theory, visit: http://www.ucmp.berkeley. edu/diapsids/avians.html

Check out birds' family tree at: http://phylogeny.arizona.edu/ tree/eukaryotes/animals/ chordata/dinosauria/aves/ neornithes.html

RELATED ARTICLE: Runway to Flight

Cladistics is a method scientists use to rank and group organisms according to characteristics, shared with a common ancestor. This family tree, or cladogram, doesn't show birds' direct ancestry, but rather how wing traits evolved in dinos birds at different times.

Sinosauropteryx The first dinosaur discovered with feather-like structures along its back. Like modern-day birds. sinosauropteryx had three fingers on each hand.

Velociraptor A flexible wrist. a requirement for flight, allowed this ferocious dinosaur's hand to swivel so it could catch prey.

Unenlagia This flightless dino. whose name means "half bird." could move its arms up and down, somewhat similar to a bird flapping its wings.

Protarchaeopteryx Symmetrical feathers on its arms and tail indicate that this dinosaur could not have flown.

Caudipteryx This dinosaur was a fast runner, but its feathers couldn't have helped it lift off the ground.

Archaeopteryx This ancient bird had streamlined and asymmetrical feathers that helped its wings slice through the air for flight.

Eoalulavis Feathers attached to its thumb gave this bird control and maneuverability while flying at low speeds.

Crow The crow and other modern birds have fully developed the art of flying, assisted by their shortened tailbones and broad wing surfaces

RELATED ARTICLE: Ruffled Feathers

Are birds dinosaurs? Here's what bird scientists have to say.

Quick: picture a dino. Giant, ferocious sweet, feathery little chirpers, right? Well, considerable evidence supports the widely accepted theory that birds are modern-day dinos. Still, a few ornithologists bristle at the idea. They insist that birds are a group separate and distinct from dinos.

Even the new feathered fossils don't convince them of the dino-bird link. Ornithologist Alan Feduccia claims the feathered fossils Chinese paleontologists recently found were not of dinos, but of flightless birds. "They're what I call `Mesozoic kiwis'," he says. (The Mesozoic era, which began about 225 million years ago and ended 65 million years ago, spans the period when dinos roamed Earth.) "Like modern kiwis, these flightless birds descended from a flying ancestor," Feduccia adds. He points to the creatures' elongated feathers and shortened tail as proof of their "flying past."

Feduccia voices other objections to the dino-bird theory:

* Archaeopteryx, the earliest known bird, dates back to 150 million years ago. The theropod dinosaurs that paleontologists lump together with birds appeared 75 million years later. So how could these dinos have given rise to birds?

"We're not talking about one being the ancestor of the other," refutes paleontologist Luis Chiappe. Also, just because scientists haven't found theropod fossils the same age as the archaeopteryx doesn't mean these dinos weren't around at the same time, he explains. The fossil record is so poor "we're getting a very incomplete sample of what's out there," adds paleontologist Mark Norell.

* The dino-bird theory doesn't adequately explain how birds started to fly. Feduccia thinks birds evolved flight by first launching themselves from tree to tree, just like flying squirrels. Paleontologists, on the other hand, speculate that small, two-legged dinos raced on the ground and found that flapping their feathery arms helped them speed up. Eventually, they reached lift-off. "I know of no aerodynamic engineer who buys into this ground-up origin of flight," scoffs Feduccia.

* Dinosaurs and birds may have similar anatomies because they shared a common ancestor, which probably lived in the Triassic period, the earliest period of the Mesozoic era. Also, it's not unusual for two animals from different lineages to look alike, especially when they have very similar lifestyles. This process, called convergent evolution, is apparent in dolphins and sharks--one's a mammal, the other's a fish.

What would convince Feduccia that birds are dinosaurs? "What paleontologists need to find are some bird-like feathered dinosaurs in the right time period with the right characteristics," he responds.

THINK ABOUT IT:

Are birds living dinos? Research your opinion and present your evidence in class. Be prepared to ruffle some feathers!

RELATED ARTICLE: CREATURE FEATURES

Scientists point to the skeletal similarities between birds and theropod dinosaurs to prove the dino-bird connection. Here are some traits the two animals share:

1. Collarbones fused to form a wishbone and breastbone 

2. Long, thin shoulder blades

3. Hollow, thin-walled bones

4. Crescent-shaped wrist bones

5. Three-fingered hands

6. Backward-facing pubic bone 

7. Bone structure and muscles for walking on two legs

8. Three forward-pointing toes and a big toe, which fully faces the rear in birds and only partially in dinosaurs