It appears that our earliest lineage really did operate in the trees.
Of course, it is way back then when it was a bare beginning and the
primate linage could be barely imagined from the evidence at hand.
We are also now reconstructing a full image using x-rays and
computers to avoid actually damaging the rock. This is great news as
there is plenty of potential data there easily lost on exposure.
From now on, I would expect bone beds to be readily processed in this
manner to produce the maximum possible data.
This particular 'ancestor' was about the size of a mouse.
Ancient Primate
Skeleton Hints at Monkey and Human Origins
By Tanya Lewi
The oldest
well-preserved skeleton of a primate, a 55-million-year-old specimen
found in China, has been discovered, researchers report.
The primate appears to
be the most primitive known relative of the group that
contains tarsiers, small primates found only in Southeast Asia.
The finding suggests this group diverged from anthropoids, the group
that contains monkeys, apes and humans, during the Eocene epoch (55.8
million to 33.9 million years ago), a time of widespread warming.
It's not the oldest
primate fossil, researchers say, but it is one of the oldest
most-complete skeletons of the group known as tarsiiformes.
"This discovery
is really exciting," vertebrate paleontologist Jonathan Bloch of
the University of Florida's museum of natural history told
LiveScience, "because it shows us the first really
[well-articulated] skeleton of one branch of the crown primate
tree," (the group including all primates alive today and their
common ancestor). Bloch was not involved in the study.
The fossil confirms
speculation that the earliest primates probably lived in trees, ate
insects and were active during the daytime.
The primate, now
named Archicebus achilles (roughly translated as "ancient
monkey"), would have weighed about 1 ounce (20-30 grams),
suggesting the earliest primates were very small. The skeleton shares
some features of tarsiers and some of anthropoids. For instance, the
specimen's heel bone strongly resembles those of anthropoids, hence
the species name, "achilles."
According to the
researchers, this fossil and other evidence suggest the first steps
of primate evolution took place in Asia, rather than Africa. But
Bloch and others disagree with this interpretation.
"Crown
primates appeared simultaneously in North America, Europe and Asia 56
million years ago," Bloch said. "I don't think this
specimen tells us much about where primates themselves evolved,"
he added.
The fossil was dug up
from an old lake bed in central China's Hubei Province, close to
where the Yangtze River now flows.
The fossil was
scanned with X-rays at the European Synchrotron Radiation Facility
(ESRF) in Grenoble, France, to produce a 3D digital reconstruction
without damaging the specimen.
The Archicebus
skeleton is roughly 7 million years older than the previously known
oldest fossil primate skeletons, which include Darwinius from Messel,
Germany, and Notharctus from the Bridger Basin, Wyoming.
Archicebus is not
the oldest primate, anthropologist Mary Silcox of the University of
Toronto Scarborough, Canada, told LiveScience. Nevertheless, "this
new species will significantly impact our understanding of what is
primitive for the common ancestor of living primates," Wilcox
said.
The findings were
reported online today (June 5) in the journal Nature.
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