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Illustration:
Portia Sloan for IVPP |
Incisivosaurus:
A Strange New Dinosaur From China
by
David Board
9/21 If you had a hunch weird- looking
creatures roamed the earth 128 million years ago, your suspicions
have just been confirmed. The evidence is a newly discovered
dinosaur called Incisivosaurus gauthieri, the oldest known oviraptorosaur.
It's often been suggested that Oviraptors
were egg-eaters. Incisivosaurus probably did not eat eggs. And there
are many other distinguishing characteristics of this new bipedal
dinosaur.
Incisivosaurus
has probably the most unique teeth from front to back of any similar
dinosaur. One of the characteristics of reptiles is undifferentiated
teeth. That is, their teeth are mostly the same shape and size from
the front to the back of their mouths. Mammals, on the other hand,
may have molars, premolars, canines, and incisors-all very unique
from one another-in the same mouth. Incisivosaurus approaches this
kind of variation in tooth structure and size with its large,
beaver-like front teeth and it's row of tiny peg-like cheek teeth
behind.
These
smaller teeth behind the large front teeth resemble those of known
plant eaters like Brachiosaurus and Apatosaurus. If so, Incisivosaurus
would be the first of the theropod dinosaurs-the group of
meat-eaters which includes T. rex and Velociraptor-to exhibit
evidence for a herbivorous diet in it the design of its teeth.
But its the front teeth of Incisivosaurus
that really stand out-literally. The Chinese paleontologists who
studied the fossil describe them as "greatly enlarged" and
see similarities to teeth in rodents who use their buck-teeth for
gnawing.
It has recently been suggested that Oviraptorosaurs
may have been a group of early birds that lost the ability to fly,
similar to ostriches. Incisivosaurus, however, refutes this idea
because it appears to be an early oviraptorosaur but lacks many
bird-like skeletal features. This suggests that oviraptorosaurs as a
group were more distantly related to birds and not an assemblage of
secondarily flightless birds.
The description of Incisivosaurus was
published in the science journal Nature.
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