Allosaurus fragilis (Jurassic,
140 million years) was a large theropoddinosaur with
a length of up to 12 meters, and can be recognized by sharp claws
on hands and feet and sharp, serrated teeth. The skull shows evidence
of being composed of separate modules, which could be moved in relation
to one another, allowing large pieces of
meat to be swallowed. A famous fossil
bed can be found in the Cleveland Lloyd Quarry in Utah,
USA.
This fossil bed contains over 10,000 bones of mostly Allosaurus. It
is still a mystery how the remnants of so many allosaures can be found
in one place, because normally the ratio of fossils of carnivorous
animals over fossils of plant eaters is very small. Findings like
these can be explained by pack hunting, although this is difficult
to prove.
The
skeleton
of
allosaurus
and
of
all
theropods
shows
birdlike
features
like
fragile,
hollow
bones