They're not quite Neanderthals and not quite
modern humans. They're something else, but
no one is sure what.
Newly-examined fossils suggest that an
unknown species of human was roaming parts
of northern China between 60,000 and 120,000
years ago. Alternatively, the fossils could be
the result of interbreeding between two of the
known species.
We know there were as many as four other
early humans living on Earth when modern
humans were still confined to Africa. The
Neanderthals lived in Europe, the Denisovans in
Asia and the "hobbit" Homo floresiensis in
Indonesia: plus there was a mysterious fourth
group from Eurasia that interbred with the
Denisovans.
The new findings suggest the picture is even
more complicated.
The Chinese remnants were first discovered in
a cave in the Xujiayao site in 1976. They
consist of some skull fragments, and nine teeth
from four individuals. A comprehensive analysis
of the teeth has now been published in the
American Journal of Physical Anthropology.
Teeth are like 'landscapes in
miniature'. Each of those slopes, grooves,
valleys define a pattern or combination of
features that can be distinctive of a
population
María Martinón-Torres of the National Research
Centre on Human Evolution in Burgos, Spain
and her colleagues looked at the size and
shape of the crown and root system, the
grooves, cusps and crests, and their positions
relative to each other. These were then
compared to a pool of over 5,000 teeth
representing nearly all the known hominin
species.
"Teeth are like 'landscapes in miniature'," says
Martinón-Torres. "Each of those slopes,
grooves, valleys define a pattern or combination
of features that can be distinctive of a
population."
It was clear that the teeth did not resemble
those of modern humans, H. sapiens. Instead,
they have several primitive features, some of
which look like the older species H. erectus,
while some look more like Neanderthals.
Other skeletal parts found at the same
site, described last year , don't neatly fit the
known species either.
Nevertheless, Martinón-Torres is reluctant to
claim that the teeth represent a new species.
"What we have seen is an unknown group for
us," she says. "It's not H. sapiens and it's not
H. neanderthalensis . They have a mixture of
something very primitive, which is currently
unknown. We cannot go further to say it's a
new species because we need to compare it to
other things."
They might actually fit an existing species.
"They could even be Denisovans," adds
Martinón-Torres.
The Denisovans co-existed and even interbred
with us. But hardly anything is known about
them. The only fossils come from a cave in
Siberia and consist of two teeth and a tiny
finger bone. DNA analysis revealed that they
were distinct from both Neanderthals and
modern humans but had aspects of both.
The Xujiayao teeth show a similar pattern,
Martinón-Torres says.
Not everyone agrees. While the sample is
small, it "strongly suggests the presence of a
previously unrecognized species," says Darren
Curnoe of the University of New South Wales in
Sydney, Australia. "There's little doubt in my
mind that these teeth stand out as something
unique." The surface features on the teeth
alone should be enough to argue for a new
species, he says.
Conceivably the remains come from a
hybrid of modern humans and Denisovans,
but that is pure speculation
Curnoe previously described another set of
mysterious hominin fossils from China, the " Red
Deer Cave People ", though these lived more
recently than the Xujiayao hominins.
Others echo Martinón-Torres' caution. Matthew
Skinner of the University of Kent, UK says
fossil samples from Asia are so sparse that it
is hard to infer species status.
Fred Spoor of University College London in the
UK agrees with Skinner. He says the remains
show a mix of modern and primitive features.
"What it means is another matter." Conceivably
the remains come from a hybrid of modern
humans and Denisovans, "but that is pure
speculation".
Many of the supposedly separate Homo
species might just be variants of a single
species, says Erik Trinkaus of Washington
University in St Louis, Missouri. "As the fossil
record fills in, most of the purported gaps
between such 'species' are gradually
disappearing," he says. "Real species in the
real world, especially for large bodied animals
like us, are widespread and variable."
On that view, finding teeth that don't fit the
known "species" just isn't surprising.
More bones would help, and they might turn up
soon, as parts of Asia are turning out to be rich
in fossils.
But it may be that only DNA evidence will offer
definitive answers, says Matthias Meyer of the
Max Planck Institute for Evolutionary
Anthropology in Leipzig, Germany. "It would be
great to get more data from east Asia, but
obviously, this is difficult."
"There was probably more than one species of
early human in Asia, which wouldn't be
surprising considering the size of the continent
and how isolated it is," says Martinón-Torres.
Last year she helped describe some teeth from
the same time period in east China, which also
did not neatly fit the known species.
Some of these populations could even have
been ancestors of modern Europeans,
according to some researchers. Most think
Africa was the cradle of modern humans, so
this is controversial. But Martinón-Torres thinks
people will return to the idea, as more and
more Asian fossils are analysed.
Curnoe agrees. "We've neglected East Asia for
far too long," he says.
"Now we're starting to get a few surprises that
don't fit with conventional wisdom based on
fossils from Europe and Africa."

One slowpoke would soon come and draw a full half-human creature by just looking at teeth fossils.

wit all d well we don dig for lag before borehole dey rain. i no eva see fossil lol.

Animals or human? ?

Summary then I will comment

If only I can read all that