The recent discovery of 800,000-year-old fossils may provide an insight into the last common ancestor of modern humans and Neanderthals
THE last common ancestor of
modern humans and their extinct
cousins, the Neanderthals, may
have been found. The claim was
made by Spanish palaeontologists
after they found 800,000-year-old
fossils, in May, in an ancient lime-
stone cave in Spain, which they say
represent an entirely new species.
Other scientists are, however,
sceptical about these claims. They
agree that the fossils, whatever
their species, are the remains of the
earliest known Europeans. As such,
the fossils are critical to the understanding of how Europe was first
inhabited by hominids, the family
of all human species. But the scientists have expressed serious reservations about assigning the Spanish
fossils a separate limb on the family tree.
A team of palaeontologists, led by
low M Bermudez of the National
Museum of Natural Sciences and Juan
Luis Arsuaga of the Complutense
University, both in Madrid, made their
case for a new hominid species after
examining the bones of a boy with a
remarkably modern face. The partial
remains of the boy - about 10- 11 years
old - and five other individuals, were
discovered two years ago at the Gran
Dolina cave in the Atapuerca hills near
Burgos, Spain.
The boy's cranium, lower jaw and
teeth, were seen by researchers as primitive. But between the brow and the jaw, the sunken cheeks, the projecting nose
and other traits suggested "a completely
modern pattern of midfacial topography", the palaeontologists wrote in a report in Science. This combination of modern and primitive characteristics seem to set the Atapuerca boy apart
from any previously recognised species,
they said. No hominid had been known
so have developed such a modern face
carber than 200,000 years ago. And the
primitive aspects do not seem to be like
those of the Homo Heidelbergensis, the
Heidelberg Man of 50-0,000 years ago,
which is the earliest known hominid in
western Europe.
The Spanish team invited further
controversy by identifying Homo antecessor - the name given to the species and derived from the Latin for "going
before" - and not Homo Heidel-bergensis or the even earlier Homo erectus - as the probable common ancestor
of Neanderthals and modern humans,
the Homo sapiens. The robust, heavy-
browed Neanderthals appeared in
Europe about 200,000 years ago and
vanished about 28,000 years ago. Many
scientists think that Homo sapiens
evolved in Africa 200,000 to 100,000
years ago and arrived in Europe about
40,000 years ago.
A journal quoted Antonio Rosas,
another palaeontologist from the
Madrid museum and member of the
team, as saying that the boy's facial traits
are "exactly the morphology we would
imagine in the common ancestor of
modern humans and Neander-
thals". According to the Spanish
researchers, one way to account for
the Homo antecessor's role as the
ancestor to both Neanderthals and
modern humans, is to postulate the
origin of the new species in Africa,
although no similar fossils have
been found there. Some members of
the Homo antecessor in Africa gave
rise eventually to Homo sapiens,
according to the hypothesis, while
others migrated to Europe, possibly
about a million years ago. The
European branch then evolved into
Homo Heidelbergensis, which in
turn evolved into Neanderthals.
But many palaeontologists are
not yet prepared to accept the Homo
antecessor as a distinct species. "I am
reluctant to endorse this new
species," said Philip Rightmire, a
palaeontologist at the State University
of New York at Binghamton. "I wonder
if the facial characteristics of one juvenile are really diagnostic. It's tricky to compare children to adults and on that
basis, establish a new species."
Fred H Smith, a palaeontologist at
Northern Illinois University in DeKalb,
who specialises in European hominids,
said that the Gran Dolina fossils were
"interesting and important", but were
"insufficient evidence for a new
species". Smith said that the fossils
would probably turn out to be either an
early Homo Heidelbergensis or late
Homo erectus.
Rosas said that the few pieces of
facial bones from some adults collected
in the Dolina cave - a discovery that
was announced in 1995 - also showed
characteristics similar to the features
found in the boy's face. He insisted
that the team had enough evidence to
support the designation of a new
species, although "people are probably
going to need some time to accommodate this proposal".
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