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Dromaeosaur
"Running
Lizard"
EARLY TO LATE to
CRETACEOUS PERIOD: 110 - 65
million years ago
The
dromaeosaurs are popularly known (especially in the movie "Jurassic
Park") as "raptors", a group of fascinating extinct
creatures. They were a group of meat-eating small to medium size
bird-like theropod dinosaurs.
Dromaeosaurs
first evolved in the Early Cretaceous and survived right up to the end of
the Late Cretaceous suggesting they were adaptable and capable hunters,
surviving such a prolonged period yet, remaining virtually unchanged in
overall design. Isolated fossil teeth have been discovered as early
as the Middle Jurassice Period from England but the lack of any skeletal
remains should preclude making scientific statements about their
definitive existence at this earlier time.
Raptors ranged in size from
about the size of a small dog
on
up to 20 feet long with some remains of Utahraptor indicating this
dromaeosaur exceeded 35 feet in length! They are theropods that possessed specialized
features: a well-developed slashing talon on their second toe, a stiffened
tail, and large grasping hands.
The
"killing claw" of raptors was a terrifying and incredibly efficient
weapon. As they moved, it was held off the ground and fully retracted. When the
muscles of the toe were contracted, the claw swept down quickly, providing for
a powerful slash that may have been able to disembowel prey swiftly. The
stiffened tail would have been good to stabilize the body while the grasping
arms and jaws held onto the prey for balance. It has been suggested that raptors could
have performed leaps onto large prey and used all four limbs to rip wounds in
them.
Raptors
were ferocious predators that some scientists believe hunted in packs and
attacked much larger dinosaurs by slashing their underbellies. It is
also believed that they were similar to lions in predatory behavior,
preferring ambushes and quick chases using their high maneuverability
along with strategic pack-hunting tactics. A human could be torn to
shreds by a pack of raptors in less than 30 seconds.
Recent
discoveries in China have shown feathered species existed. Some
remains have been found fully covered in feathers and with developed
wings. Others even had what appear to be secondary gliding wings
on their legs. This has
revolutionized paleontologists' view of what not only these creatures
could have looked like when alive, but of possible plumage on other theropod dinosaurs. Dromaeosaurs share other characteristics with
birds and theories now place these vicious predators as being the earliest
ancestors of birds.
Dromaeosaur
fossils have been found in North America, Europe, Africa, Japan, China,
Mongolia, Madagascar, Argentina, and Antarctica.
Misspellings:
Dromiosaurs, Dromeosaurs, Dromosaurs, Dromosars, Dromaoesaurs
- copyright Paleo Direct, Inc.,
(art by Mineo Shiraishi / Frank Denota)
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