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Once found almost entirely
in the western United States and ill Asia, dinosaur fossils are now being
discovered on all seven continents. A host of new revelations emerged in 1998
that promise to reshape scientists' views of dinosaurs, including what they
looked like and when and where they lived.
It is doubtful that
Tyrannosaurus Rex had lips or that Triceratops had cheeks, says Lawrence Witmer,
an assistant professor of anatomy at Ohio University in Athens, Ohio. Witmer was
a leading researcher for a study on dinosaur anatomy that was presented at the
annual meeting of the Society for Vertebrate Paleontology, which concluded on
October 3 in Snowbird, Utah.
Witmer’s study reached its
conclusions by using high-tech computerized axial tomography ( CT or CAT) scans
&long with comparative anatomy studies. For example, the theory that
Triceratops and similar dinosaur species had cheeks was based on past
comparisons with mammals such as sheep. But Witmer’s careful analysis found the
structure of the tricera tops jaw and skull made it more likely that Triceratops
had a beak like that of an eagle. Witmer said that scientists should use birds
and crocodiles as models when researching the appearance of dinosaurs.
In early October scientists announced that they had confirmed the
discovery of a new type of ceratopsian dinosaur. The dinosaur's bones, found in
New Mexico in 1996, are forcing paleontologists to rethink their theories about
when ceratopsians migrated to what is now Noah America.
Scientists previously thought that ceratopsians, the group that included
the well-known Triceratops, arrived in North America from Asia between 70
million and 80 million years ago. During this time, the late Cretaceous Period,
the cash’s two supercontinents m Laurasia in the north and Gondwanaland in the
south -- were in the process of pulling apart, cutting dinosaur populations off
from each other and interrupting migratory patterns.
The
fossilized bones, found by eight-year-old Christopher Wolfe and his father,
paleontologist Doug Wolfe of the Mesa Southwest Museum in Arizona, date to about
90 million years ago. This could mean that ceratopsians originated in Noah
America and migrated to Asia rather than the reverse, paleontologists said. Doug
Wolfe named the important new species of dinosaur Zuniceratops christopheri
after his son.
An expedition from the Universities of Alaska in
Anchorage and Fairbanks has discovered a region in remote northern Alaska so
rich in fossilized dinosaur tracks that team members dubbed it the "dine
expressway". The trampled area was found during the summer of 1998 on Alaska’s
Noah Slope near the Brooks Range.
The tom found 13 new track
sites and made casts from the prints of five different types of dinosaurs. The
rock in which the prints wore found dates to more than 100 million years ago, or
about 25 million years older than the previously discovered signs of dinosaurs
in the Arctic region. Paleontologists said that the new findings provide
important evidence that dinosaurs migrated between Asia and Noah America during
the early and mid-Cretaceous Period, before Asia split off into its own
continent.
Two rich fossil sites in the hills of Bolivia have
been recently discovered, exciting paleontologists and dinosaur buffs. This
discovery includes one of the most spectacular dinosaur trackways over
found,
The discovery of a large site in the mountain region of
Kila Kila in southern Bolivia was announced in early October. Here scientists
found the tracks of at least two unknown species of dinosaur. These included a
large quadruped ( four-foot ed) dinosaur that wall probably about 20 m ( about
70 ft) long.
The other site, located not far from the Bolivian
city of Sucre, was uncovered in a cement quarry by workers several years ago but
was not brought to paleontologists' attention until the middle of 1998. The site
features a vertical wall covered with thousands of dinosaur prints representing
more than 100 different species. The tracks date back to between 65 million and
70 million years ago. Since dinosaurs are believed to have died out around 65
million years ago, the prints were likely made by some of the last dinosaurs on
cash.
Scientists speculated that the tracks were made at the
edge of a lake or swamp and were then hardened and preserved, The rock
containing the tracks was then pushed into a vertical position over millions of
years of geologic activity. Dinosaur eggs have also been found at the site,
which paleontologists are working to preserve before it falls victim to erosion.
Paleontologists hope to study the site and learn about the diet and physical
characteristics of the dinosaurs that are represented there,