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2 new african dinoaurs



CACHE OF DINOSAUR SKELETONS UNEARTHED 

 'SURPRISE':   Two new species call into question theories of continental
breakup.
By BOYCE RENSBERGER 
Washington Post 

Buried in the sands of the Sahara in Niger, 500 miles from the nearest road,
paleontologists have discovered a major trove of dinosaur skeletons,
including two from previously unknown species.

One, for example, is a meat-eating predator that looked like a scaled-up
version of Velociraptor, the villain of the movie ''Jurassic Park,'' or a
scaled-down version of Tyrannosaurus rex. The other new dinosaur was a
four-legged, plant-eating sauropod akin to a brontosaur.

When the dinosaurs were alive, the region that is now arid desert was an Eden
-- a lush, tropical habitat near the equator with conifer trees, streams and
ponds.

The discoveries are leading scientists to question a long-standing assumption
about how the breakup of the ancient supercontinent Pangaea affected dinosaur
evolution. This is because the new African dinosaurs seem to have resembled
their North American cousins, whose continent broke away long ago, more
closely than they resembled the dinosaurs of South America, which was linked
to Africa until more recent times.

The discovery indicates present-day Africa was connected to Europe by a land
bridge at Gibraltar longer than had been suspected, the researchers said.

''That was a surprise,'' said Paul Sereno, a University of Chicago
paleontologist who led the group that found the skeletons. Sereno and his
colleagues published their findings in this week's issue of the journal
Science.

When dinosaur evolution began, about 225 million years ago, there was just
one land mass -- Pangaea -- and the great beasts are thought to have
inhabited much of it. Then about 170 million years ago, Pangaea split into
two land masses: a northern section called Laurasia (including the future
North America, Europe and Asia) and a southern portion called Gondwana
(comprising the crustal plates that would become South America, Africa,
India, Antarctica and Australia).

This event, according to the old assumption, split the dinosaur world into
two parts, each of which would go on evolving independently.

Then, about 40 million years later, Gondwana began to break up and South
America parted from Africa. The dinosaurs that Sereno found date from shortly
after this time -- the early Cretaceous, around 130 million years ago. This
is why it was expected that African dinosaurs -- relatively few of which have
been found until now -- would resemble South American types.

Sereno has named the new predatory dinosaur Afrovenator abakensis, which he
said means ''African hunter from In Abaka,'' the region of Niger where the
bones were found. It stood 7 feet tall at the hip and stretched 27 feet from
head to tail.

The herbivorous dinosaur has not been named but is unusual because it
represents a form -- typified by broad teeth -- that was thought to have
become extinct more than 20 million years earlier. It was about 55 feet long.
Its thigh bone is six feet long.

''It is very likely that they were prey and predator,'' Sereno said of the
two discoveries.


IF YOU'RE INTERESTED

The expedition last fall that found the new dinosaurs -- among nearly six
tons of dinosaur bones -- will be the subject of Wednesday's episode of ''The
New Explorers'' series on PBS.


MERCURY CENTER ID: me51820d


Transmitted:  94-10-14 06:03:20 EDT