DRUMHELLER, Alberta --- Paleontologists searching the Alberta badlands have
made a fossil discovery they say supports the theory that birds are direct
descendants of dinosaurs.
Scientists working in Dinosaur Provincial Park in southern Alberta have
discovered a small beak attached to the skull of an immaculately preserved
carnivorous dinosaur known as an ornithomimid, a 75-million-year-old
ostrich-like dinosaur. The discovery of a beak on a meat-eating dinosaur
adds another layer of evidence to the theory that the prehistoric creatures
are the ancestor's of today's birds.
"This is a hotter topic than extinction," said Philip Currie. "In a way, it
means there was no extinction."
Dr. Currie is one of a half-dozen researchers exploring the theory that
dinosaurs may still be with us in the form of birds. The idea was first put
forward by zoologist Thomas Huxley but was denounced in the early 1900's
when a Danish scientist argued that birds could not be descended from
dinosaurs because dinosaurs lacked the wishbone near the chest that enables
flight.
Researchers have since found evidence of the wishbone in several dinosaur
species --- particularly the Tyrannosaurus rex --- and have also discovered
a beak in the plant eating duck-billed dinosaur. Scientists also believe
that carnivores had beaks, and Dr. Currie said his discovery finally proves it.
Dr. Currie explained that the beak, which does not protrude but rather
remains within the mouth, was likely used for tearing and cutting, in the
same manner as that of some birds of prey. The beak is composed of the same
substance as human fingernails and allowed ornithomimid to prey on small
mammals, lizards and infant dinosaurs. It has two parts, and covers both
the top and bottom of the inside of the mouth.
The dinosaur probably developed a beak after one too many run-ins with
bigger carnivores, Dr. Currie said. Ornithomimids, which stood about 2
meters tall, probably lost their teeth in an evolutionary change that made
them lighter and faster, allowing them to get away more easily from
rampaging carnivores.
"The key was to become as lightweight and agile as possible, which is
probably why their teeth were eventually replaced," he said.
In fact, there is evidence that the specimen animal, found near Brooks south
of Calgary, may have met its fate while trying to escape a tyrannosaur or
some other huge relative. The animal, which could run up to 100km/hour, has
a broken leg, which Dr. Currie believes snapped while it was still alive.
"This poor little guy probably died trying to get away."
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Hope this makes for some interesting discussion.
Darrin R. Brooker