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early dino news from Madagascar
Earliest Known Dinosaurs Found In Madagascar
By Maggie Fox, Health and Science Correspondent
WASHINGTON (Reuters) - The jawbones of two
kangaroo-sized dinosaurs found in Madagascar may
be the remains of the oldest dinosaurs ever found,
The trove of fossils unearthed on the west side of the
Indian Ocean island, already renowned for its
unusual modern-day flora and fauna, includes some of
the earliest ancestors of mammals, researchers
John Flynn of the Field Museum in Chicago and colleagues said.
The two dinosaurs were prosauropods -- plant-eaters with small heads and
long necks that could walk on two or four legs.
``They are at least as old as any dinosaurs that have been described
before,'' Flynn said in a telephone interview. ``We think they
could be the oldest known.''
Circumstantial evidence dates them to the early Triassic period, 230
million years ago, Flynn, along with colleagues at the University
of California at Santa Barbara, Northern Illinois University and the
University of Antananarivo in Madagascar report in the journal
Fossil Quality ``Exquisite''
``It's a very exciting set of discoveries because the quality of
preservation of the fossils is very exquisite and happens to come from a
time period when things were happening to both mammal and dinosaurs,''
``So we are looking at the origin of two very important kinds of fossils.''
The report describes a range of strange creatures.
``We have a series of different things -- parrot-beaked reptiles which
would have been sort of the sheep of that time,'' Flynn said.
``They would have been very abundant.''
Living nearby were the kangaroo-sized dinosaurs.
``That is a good analogy because kangaroos have powerful hind limbs and
smaller front legs,'' Flynn said. ``When (these dinosaurs)
were feeding and walking about, they probably were ambling about on all
four legs and then were able to rear up on hind legs and
feed from trees. They couldn't hop like kangaroos do but that body shape
Then there were five species of early ancestors of mammals known as
mammal-like reptiles or synapsids. These include a class
known as cynodonts.
``There is a major transition going on in this interval -- a transition
from big, cold-blooded creatures evolving into very tiny,
warm-blooded mammals,'' Flynn said.
``These very beautifully preserved skulls and skeletons will help us
understand that transition.''
Local Residents To Be Honored
None of the new species has been officially named yet but geologist Andrew
Wyss of the University of California at Santa Barbara,
who worked on the study, said some of the names would honor local residents
who found the fossil bed.
``A boy said that his older brother had found some bones,'' Wyss said in a
statement. ``So we waited around a half day for the
brother, Mena, and sure enough, he showed us a hill with a mound of them.''
Mena's name will be included in some of the new names.
Flynn said none of the rocks found in the sediments with the fossils are
suitable for use in traditional methods of radio-dating. But
other, time-honored methods suggest the dinosaurs are the earliest ever
``We have got some groups of reptiles that typically co-occur with known
early dinosaurs and those particular groups are not present
at our site in Madagascar,'' he said.
He said carbon dating is only useful back to about 50,000 years.
Flynn said 230 million years ago Madagascar was just splitting off from
what would become Africa. They were all part of a vast
land mass known as Pangea.
``It almost certainly was wetter,'' he said. ``It was even more sort of
tropical. There were big rivers running through this area. I
would imagine it being something like the Mississippi river valley.''
He said more interesting creatures may be dug up.
``We continue to identify even more sites in that area that produce
fossils,'' he said.