"Ganlea megacanina"
Carnegie Museum of Natural History artist's conception
By MICHAEL CASEY, AP Environmental Writer -
Thu Jul 2, 11:00am ET
BANGKOK, Thailand – Fossils recently discovered in Myanmar could
prove that the common ancestors of humans, monkeys and apes evolved
from primates in Asia, rather than Africa, researchers contend in a
study released Wednesday.
However, other scientists said that the finding, while
significant, won't end the debate over the origin of anthropoids —
the primate grouping that includes ancient species as well as
modern humans.
The pieces of 38 million-year-old jawbones and teeth found near
Bagan in central Myanmar in 2005 show typical characteristics of primates, said Dr. Chris Beard, a paleontologist at the Carnegie Museum
of Natural History in Pittsburgh and a member
of the team that found the fossils.
"When we found it, we knew we had a new type of primate and
basically what kind of primate it was," Beard said in a telephone
interview from Pittsburgh. "It turns out that jaws and teeth are
very diagnostic. ... They are almost like fingerprints for fossils
like this."
The findings were published in the Proceedings of The Royal
Society B, a London-based peer-reviewed journal.
Beard and his team from France, Thailand
and Myanmar concluded that the fossils — which they dubbed Ganlea
megacanina — came from 10 to 15 individuals of a new species that
belonged to an extinct family of Asian anthropoid primates known as
Amphipithecidae.
Wear and tear found on the canine teeth
suggest the tree-dwelling, monkey-like creatures with long tails
used their teeth to crack open tropical fruit to get to the pulp
and seeds — behavior similar to modern South American saki monkeys that inhabit the Amazon basin, Beard
said.
"Not only does Ganlea look like an anthropoid, but it was acting
like an anthropoid 38 million years ago by having this feeding
ecology that was quite specialized," Beard said.
His team determined that the fossil was 38 million years old,
making it several million years older than any anthropoid found in
Africa and the second-oldest discovered in Asia.
In 1994, Beard and his Chinese colleagues found fossilized foot
bones of the anthropoid Eosimias — one of the worlds smallest
primates — which lived between 40 million and 45 million years ago
and roamed ancient rain forest on the eastern coast of China.
Beard said the age of both fossils was the evidence he needed to
challenge contentions that anthropoid primates had evolved in
Africa, where Lucy, a 3.2 million-year-old fossil, was discovered
in 1974.
"This new fossil Ganlea definitely helps us argue — and we think
the argument is pretty close to settled now — that when you go back
this far in time, the common ancestor of monkeys, apes and humans
was definitely in Asia, not in Africa," Beard said.
In May, researchers unveiled a nearly intact skeleton of a 47
million-year-old primate — found in Germany and dubbed "Ida" — that
they said provides a glimpse into how our distant ancestors may
have looked.
"We wouldn't claim Ganlea is missing link, but we know Ganlea is
much more closely related to our ancestors than Ida ever was — even
though, unfortunately, we don't have complete skeleton like they
did for Ida," he said.
Jorn Hurum, who brought Ida to the University of
Oslo Natural
History Museum, said that it was too early to draw
conclusions from the Myanmar fossils because
only jawbones and teeth were found.
"These fragments are still too few and far between," Hurum said.
"This is the kind of scientific debate that will continue until
more complete skeletons like Ida has been found, and this may take
several hundred years."
Stony Brook University Prof. John G. Fleagle, a paleontologist,
said the discovery of Ganlea is important because it shows how
several different primates found in Myanmar are related and
provides interesting suggestions about a unique dietary
specialization.
But he said the Myanmar fossils do little to prove whether
anthropoids evolved in Asia or Africa — or even whether Ganlea was
an anthropoid or an early relative of lemurs.
"This doesn't add anything new about whether anthropoids came
from Africa or Asia or the broader evolutionary relationships of
these particular primates ," Fleagle said.
"The definitive features that would resolve it in people's mind
would be in the skull," he said. "Without a skull to demonstrate
the distinctive anthropoid features of the eye and ear regions,
scientists will still continue to debate whether the dental
similarities just indicate similar diets or are the result of a
common heritage."
Beard isn't letting the criticism slow him down. He and his team
expect to return in November to Myanmar to continue searching for
more fossils and exploring how anthropoids evolved in Asia and then
migrated to Africa.
"The question is when and how did this big evolutionary shift
occur from Asia to Africa," Beard said. "That is something we are
trying to establish. We have a team working in Myanmar which has
ideas of places to go in Africa to try and pick up thread
there."