Link in msg below takes you to NIU page which has pdf version of a 12
page paper on the find. I think this is from the J Human Evol article
referenced below.
Howard
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Fossils of Tiny Primates Found
Wednesday, 15 March 2000 (AP)
SOME ANCESTORS of monkeys, apes and humans were so tiny that they could
have stood atop a person's thumb - a new finding astonishing even to
anthropologists.
Fossilized foot bones from two species smaller than any other known
creature on the primate family tree were found at a limestone mine in
eastern China. The bones are each about the size of a grain of rice.
"This discovery reinvents our definition of what the primate order is
all about and how it arose," said Richard Stucky, curator at the Denver
Museum of Natural History. He said he was "almost at a loss for words."
At one-third of an ounce - the weight of a couple of pencils - the
smaller of the two species is dwarfed by the 1-ounce Madagascar mouse
lemur, the smallest known primate alive today. The two lived in a rain
forest about 45 million years ago, feeding on insects and sap.
Scientists from Carnegie Museum of Natural History, Northern Illinois,
Northwestern and the Chinese Academy of Sciences in Beijing detail the
species in this week's Journal of Human Evolution.
In a separate article in the journal Nature, the group reported on more
fossils from a previously discovered third primate called Eosimias
centennicus. They had discovered its teeth and jaws in the mid 1990s.
Now they've got ankle bones, which they say backs up their controversial
claim that Eosimias is an early ancestor of humans.
Eosimias and the two new tiny species all lived together around the time
when lower primates split from the higher primates.
Lower primates include lemurs. Higher primates include humans. The split
happened 40 million to 50 million years ago.
At 3 ounces, Eosimias was larger than the tiny species, which have not
been named.
The smaller of the two new species might have been below Eosimias on the
evolutionary branch, a common ancestor of higher primates and some lower
primates, said Chris Beard of the Carnegie Museum.
The larger one - weighing half an ounce - appears to be a higher
primate, perhaps in the same family as Eosimias.
"Nobody would have believed that as recently as 45 million years ago,
our ancestors were about the size of a shrew," Beard said.
Anthropologists expected to find a smallish creature at the fork between
higher and lower primates.
Because it would have needed to eat insects voraciously to keep up with
an overheated metabolism, it would have had higher primate features: two
eyes facing forward and soft hands without claws, all the better to
focus on and grab bugs.
"That said, these are really tiny," said Brian Richmond, a George
Washington University researcher.
Unlike modern higher primates, which are social and move about in the
daytime, these creatures' tiny size would have forced them to hide
during the day and feed at night.
The tiny species are the smallest of 12 to 16 species of little primates
found at the Chinese mine.
Eosimias is among them. Its ankle bones are further proof the creature
was a higher primate, Beard said. It apparently walked on all fours,
because like monkeys that scurry atop tree branches, their feet faced
downward. Lower primate cling to tree trunks, so their feet face inward.
But the evidence of Eosimias' status as a higher primate is still not
conclusive. Richmond said it is possible Eosimias was a lower primate
that evolved a few characteristics similar to higher primates.
Also, Beard's team has not found a skull or full skeleton. They inferred
the ankle fossils to be Eosimias' based on where they were found.
Stucky is convinced, calling it "significant, additional evidence" that
Eosimias is a higher primate.
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On the Net: Researchers' site: http://www.niu.edu/pubaffairs/primate
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