Kurt (Sphincter) Schlichter
2017-08-10 23:01:41 UTC
http://www.sciencemag.org/news/2017/08/ancient-infant-ape-
skull-
sheds-light-ancestor-all-humans-and-living-apes
*Ancient Infant Ape Skull Sheds Light on the Ancestor of All
Humans and Living Apes* by Michael Price
Aug. 9, 2017
Anthropologists have waited decades to find the complete
cranium of a Miocene ape from Africa -- one that lived in the
hazy period before the human lineage split off from the common
ancestors we share with chimpanzees some 7 million years ago.
Now, scientists in Kenya have found their prize at last: an
almost perfectly preserved skull roughly the size of a
baseball. The catch? Itâs from an infant. That means that
although it can give scientists a rough idea of what the common
ancestor to all living apes and humans would have looked like,
drawing other meaningful conclusions could be challenging.
âThis is the sort of thing that the fossil record loves to do
to us,â says James Rossie, a biological anthropologist at the
State University of New York in Stony Brook who wasnât
involved with the study. âThe problem is that we learn from
fossils by comparing them to others. When there are no other
infant Miocene ape skulls to which to make those comparisons,
your hands are tiedâ.
The remarkably complete skull was discovered in the Turkana
Basin of northern Kenya 3 years ago. As the sun sank behind the
Napudet Hills west of Lake Turkana, primate paleontologist
Isaiah Nengo of De Anza College in Cupertino, California, and
his team started walking back to their jeep. Kenyan fossil
hunter John Ekusi raced ahead to smoke a cigarette. Suddenly he
began circling in place. When Nengo caught up, he saw a
dirt-clogged eye socket staring up at him. âThere was this
skull just sticking out of the ground,â Nengo recalls. âIt
was incredible because we had been going up and down that path
for weeks and never noticed itâ.
The team carefully extracted the fossil from the rocky ground
using small dental picks and brushes. Nengo knew immediately it
was a primate skull, but that he wouldnât learn much more
until he and colleagues performed a more sophisticated
analysis.
At the Noble Gas Laboratory at Rutgers University in New
Brunswick, New Jersey, researchers measured argon
isotopesâwhich decay at a fixed, predictable rateâwithin
the fossilâs rock layer, revealing that it was about 13
million years old. Back then, the dry, rocky landscape of
todayâs Turkana Basin was a lush rainforest.
Although the fossil looks a bit like a gibbon skull on first
blush, Nengo says, its dental pattern and teeth shape suggest
its closest relatives are other Miocene fossil primates from
the genus *Nyanzapithecus*, also found in Kenya. Yet its molars
are much larger than those of the known nyanzapithecines,
indicating a new species. The researchers named it *N. alesi*,
or Alesi for short, after the Turkana word for âancestorâ.
Extremely sensitive x-ray imaging performed at the European
Synchrotron Radiation Facility in Grenoble, France, allowed the
team to count growth lines in the fossilâs unerupted adult
teeth like tree rings, telling them Alesi was about 485 days
(or 1 year and 4 months) old when it died. The x-rays also
revealed the presence of bony ear tubes in the skull, which act
as a balance organ. Primatologists have long debated whether
the Nyanzapithecus genus belonged to the ape or monkey line,
but the presence of these tubes, combined with the size and
shape of the teeth, solidly mark Alesi -- and by extension the
other nyanzapithecines -- as apes
[http://www.nature.com/nature/journal/v548/n7666/full/nature234
5
6.html?foxtrotcallback=true], the researchers report today in
'Nature'. Whatâs more, they claim, the ear tubes present
strong evidence that itâs an evolutionary cousin to the
ancestral line of apes from which humans and living apes
derive.
That could help answer a long-standing question in primate
evolution: Did the common ancestor to living apes and humans
evolve in Africa or Eurasia? Nengo says the new finding
supports an African origin. âAfrica has been acting like a
petri dish for millions of years, conducting experiments in
evolution,â he says. âHumans and our close ape relatives
are just the latest evolutionary experiments to come out of
that petri dish.â
David Begun, an anthropologist at the University of Toronto in
Canada, isnât convinced. He points to the fact that fossil
homininesâa group whose descendants include African apes and
humansâhave been found in Europe dating to 12.5 million years
ago, but they donât conclusively show up in the African
fossil record until 7 million years ago. To him, that suggests
the common ancestor evolved in Europe before heading back into
Africa. The discovery of N. alesi does nothing to change that.
â*Nyanzapithecus* is an early ape,â Begun says. âWhether
itâs the closest thing we know to the last common ancestor...
is questionable.â ----------
Another step forward in understanding ourselves.
. . .
skull-
sheds-light-ancestor-all-humans-and-living-apes
*Ancient Infant Ape Skull Sheds Light on the Ancestor of All
Humans and Living Apes* by Michael Price
Aug. 9, 2017
Anthropologists have waited decades to find the complete
cranium of a Miocene ape from Africa -- one that lived in the
hazy period before the human lineage split off from the common
ancestors we share with chimpanzees some 7 million years ago.
Now, scientists in Kenya have found their prize at last: an
almost perfectly preserved skull roughly the size of a
baseball. The catch? Itâs from an infant. That means that
although it can give scientists a rough idea of what the common
ancestor to all living apes and humans would have looked like,
drawing other meaningful conclusions could be challenging.
âThis is the sort of thing that the fossil record loves to do
to us,â says James Rossie, a biological anthropologist at the
State University of New York in Stony Brook who wasnât
involved with the study. âThe problem is that we learn from
fossils by comparing them to others. When there are no other
infant Miocene ape skulls to which to make those comparisons,
your hands are tiedâ.
The remarkably complete skull was discovered in the Turkana
Basin of northern Kenya 3 years ago. As the sun sank behind the
Napudet Hills west of Lake Turkana, primate paleontologist
Isaiah Nengo of De Anza College in Cupertino, California, and
his team started walking back to their jeep. Kenyan fossil
hunter John Ekusi raced ahead to smoke a cigarette. Suddenly he
began circling in place. When Nengo caught up, he saw a
dirt-clogged eye socket staring up at him. âThere was this
skull just sticking out of the ground,â Nengo recalls. âIt
was incredible because we had been going up and down that path
for weeks and never noticed itâ.
The team carefully extracted the fossil from the rocky ground
using small dental picks and brushes. Nengo knew immediately it
was a primate skull, but that he wouldnât learn much more
until he and colleagues performed a more sophisticated
analysis.
At the Noble Gas Laboratory at Rutgers University in New
Brunswick, New Jersey, researchers measured argon
isotopesâwhich decay at a fixed, predictable rateâwithin
the fossilâs rock layer, revealing that it was about 13
million years old. Back then, the dry, rocky landscape of
todayâs Turkana Basin was a lush rainforest.
Although the fossil looks a bit like a gibbon skull on first
blush, Nengo says, its dental pattern and teeth shape suggest
its closest relatives are other Miocene fossil primates from
the genus *Nyanzapithecus*, also found in Kenya. Yet its molars
are much larger than those of the known nyanzapithecines,
indicating a new species. The researchers named it *N. alesi*,
or Alesi for short, after the Turkana word for âancestorâ.
Extremely sensitive x-ray imaging performed at the European
Synchrotron Radiation Facility in Grenoble, France, allowed the
team to count growth lines in the fossilâs unerupted adult
teeth like tree rings, telling them Alesi was about 485 days
(or 1 year and 4 months) old when it died. The x-rays also
revealed the presence of bony ear tubes in the skull, which act
as a balance organ. Primatologists have long debated whether
the Nyanzapithecus genus belonged to the ape or monkey line,
but the presence of these tubes, combined with the size and
shape of the teeth, solidly mark Alesi -- and by extension the
other nyanzapithecines -- as apes
[http://www.nature.com/nature/journal/v548/n7666/full/nature234
5
6.html?foxtrotcallback=true], the researchers report today in
'Nature'. Whatâs more, they claim, the ear tubes present
strong evidence that itâs an evolutionary cousin to the
ancestral line of apes from which humans and living apes
derive.
That could help answer a long-standing question in primate
evolution: Did the common ancestor to living apes and humans
evolve in Africa or Eurasia? Nengo says the new finding
supports an African origin. âAfrica has been acting like a
petri dish for millions of years, conducting experiments in
evolution,â he says. âHumans and our close ape relatives
are just the latest evolutionary experiments to come out of
that petri dish.â
David Begun, an anthropologist at the University of Toronto in
Canada, isnât convinced. He points to the fact that fossil
homininesâa group whose descendants include African apes and
humansâhave been found in Europe dating to 12.5 million years
ago, but they donât conclusively show up in the African
fossil record until 7 million years ago. To him, that suggests
the common ancestor evolved in Europe before heading back into
Africa. The discovery of N. alesi does nothing to change that.
â*Nyanzapithecus* is an early ape,â Begun says. âWhether
itâs the closest thing we know to the last common ancestor...
is questionable.â ----------
Another step forward in understanding ourselves.
. . .