Protarchaeopteryx
was a small, feathered, bird-like dinosaur that lived in China. This
animal is considered to be more primitive than Archaeopteryx
as it was a little more like the non-avian theropods. The
resulted in its name "first ancient-wing" or before
Archaeopteryx, Like its namesake, the Protarchaeopteryx specimens were found
with feather impressions. The best preserved of the newest specimens
definitively shows feathers attached to the front leg and tail. Unlike
Archaeopteryx, however, Protarchaeopteryx's feathers are
symmetrical, indicating that Protarchaeopteryx may not have
been able to fly.
Discovered in 1996, Protarchaeopteryx is based on a
remarkable fossil preserved in the fine-grained stone from Liaoning,
China. It laid to rest the argument about dinosaurs being feathered.
Now discussion has shifted to the type of feathers that were on the
dinosaurs and when flight feathers evolved. Although the new fossils closely resemble Archaeopteryx in some
ways, they lack the precise form of true birds -- in particular the
length of wing and design of individual feathers. For this reason, the
researchers believe the fossils were true dinosaurs that are the
immediate ancestors of the first birds. "They represent a missing link between dinosaurs and birds which we
had expected to find," said Ji Quiang, director of the National
Geological Museum in Beijing, who worked on the fossils.
It is one of two feathered dinosaurs found in China. The
other is Caudipteryx zoui, or "tail feather." Both were fast runners
and were probably unable to fly, judging from the short arms and long
legs. Their feathers may have been for insulation or display. Protoarchaeopteryx
was about the size of a modern-day
turkey, is the more primitive and earlier of the two fossils, said
Mark Norell, who also worked on the fossils. Norell is chairman and
associate curator in the department of vertebrate paleontology at the
American Museum of Natural History in New York.
Philip Currie of the Royal Tyrrell Museum of Paleontology,
Drumheller, Alberta, Canada, said,
"For the first time we have something that is unquestionably a
dinosaur with unquestionable feathers. So what we have is a missing
link between meat-eating dinosaurs and the earliest bird.'' He
added, "This shows that dinosaurs are not extinct, but are
well-represented by 10,000 species of birds." The existence of
Sinosauropteryx and the dinosaur with even more feathers,
Caudipteryx, lends credence to the theory the
birds are descended from theropod dinosaurs and not from 4-legged
arboreal (tree living) reptiles. There are, however, dissenting voices
who point out that the new feathered fossils are from a time after
that of
Archaeopteryx, the first bird (which lived about 147 million years
ago, before Caudipteryx and Protarchaeopteryx). This suggests that
perhaps the fossils' resemblance to birds could be a case of
convergent evolution and that their feathers evolved for insulation,
not flight, indicating a warm-blooded physiology.
Protarchaeopteryx presents an interesting
contradiction. It is more primitive than
Archaeopteryx, so it should have occurred in the fossil record
before
Archaeopteryx. But that was not the case. It
appeared ten million years later. One explanation is that both species
evolved from a common ancestor, but one evolved faster than the other.
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