One of the last of the dinosaurs to
evolve, the Triceratops
lived and died during the Late Cretaceous Period - more than
136
million years ago. A large bony frill which partially encircled its
neck separated the creature's massive body and elongated head. Two
long, bony horns measuring more than three feet in length jutted from
its forehead, while another short horn curved slightly up from its
snout. The weight of its heavy body was borne by stout hind legs and
shorter forelegs, which suggested a bipedal ancestor. Paleontologists
have estimated that the Triceratops weighed eight to nine tons and
supported its enormous bulk by browsing continuously, for this dinosaur
-- like so many others of formidable appearance- was an herbivore.
Its beak-like mouth ripped fibrous vegetation such as palm fronds,
while its teeth sheared through the stringy pulp and chopped it finely
to allow for easy mastication. Scientists believe that the Triceratops
grazed and traveled in groups or herds which provided additional
protection from hungry predators such as the Tyrannosaurus Rex. A
latecomer to the Age of Dinosaurs, this species was also among the last
of the reptilian giants to become extinct.
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The late Jurassic Period produced one of the dinosaur era's most
unusual creatures- the Stegosaurus.
It developed as a biped, but through the eons it reverted to a
quadruped, thus accounting for its high haunches and short forelegs.
Measuring approximately twenty feet in length, the Stegosaurus was
armored -- with two offset rows of large, triangular, horn-covered bony
plates along its back and two pairs of long, pointed bony spikes at the
end of its tail. This battle-ready, ponderous body completely dwarfed
the creature's comically-small head and suggested a pugnacious nature.
But the Stegosaurus was a peaceably-natured dinosaur which grazed on
soft vegetation and counted on its formidable appearance to ward off
predators. Closer examination of Stegosaurus fossils in the late 1970s
revealed that the bony plates contained a network of canals which
probably contained blood vessels. Many scientists is now speculate that
the vessels served as a convective heat-loss system, enabling the
dinosaur to control its own body temperature. Such startling
information suggests that dinosaurs were warm-blooded creatures - not
cold-blooded like modern reptiles- and add extra dimension to the
continuing quest to explain their mass extinction.
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The Protoceratops
was one of the most primitive species of dinosaur. A predecessor of
later great horned dinosaurs, the Protoceratops was slightly larger
than the modern alligator and probably evolved -- like so many other
herbivores -- from a bipedal ancestor. The Protoceratops' large head
was partially encircled by a bony frill which protected its vulnerable
neck area from a predator's deadly attack, but this dinosaur lacked the
sharp horns which gave its Triceratops descendents their fierce and
combative appearance. A beak-like mouth suited its vegetarian diet, but
the creature possessed only a few teeth in its upper jaw and probably
eschewed fibrous palm fronds in favor of tender, easily masticated
shoots. The animal's well-developed tail contained long vertical
spines, indicating to some researchers a partially-aquatic lifestyle.
Like other larger herbivores, the Protoceratops traveled in groups or
herds. In recent decades, scientists have uncovered more than eighty
individual specimens in all stages of development -- from whole,
unbroken eggs complete with intact embryo to older animals at the end
of their lifecycle. These valuable finds -- many of them unearthed in
Mongolia -- will in time produce priceless additional data on this
ancient creature. The Protoceratops was one of the Dinosaur Era's first
species and one of science's most fertile sources for paleontologic
research.
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In 1842 British anatomist Sir Richard Owen coined the word dinosaur
from two Greek words meaning "terrible lizard." Although dinosaurs were
not lizards, the term aptly applied to the best known and most fearsome
of all dinosaurs -- the Tyrannosaurus.
Its name meant "tyrant lizard," and this ravenous meat-eater conducted
an unrivaled reign of terror as master of the Mesozoic Era. Towering
twenty feet above the ground, the Tyrannosaurus possessed an enormous
head and six-inch, dagger-like teeth which slashed into prey with
merciless efficiency. Its short forelimbs served little function other
than grasping objects at close range, and the behemoth's long tail
acted as a counter-balance for its cumbersome body. While the
Tyrannosaurus was undoubtedly the most powerful and dangerous dinosaur,
it was also one of the rarest. Scientists estimated that one hundred
square miles of territory served as the habitat for only one
Tyrannosaurus. Its remains are generally uncovered in the same deposits
as the remains of its most likely prey -- the more plentiful great
armored dinosaurs such as Triceratops and Protoceratops. Millions of
years after the last Tyrannosaurus died, this terrifying creature
continues to stimulate scientific investigation and linger in the
mythological fantasies of mankind.
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