Humans left Asia for Africa, then returned
- Humans left Asia for Africa, then returned
Wednesday, 1 June 2005
Three newly discovered primate species that lived 30 million
years ago suggest that our ancestors originated in Asia not
Africa, challenging the well-known "Out of Africa" theory of
But it could be something a bit more complicated, such as "Out
of Asia into Africa and Back to Asia", since some researchers
now think Asian primates journeyed to Africa, where they evolved
into humans, who then travelled both in and out of Africa.
According to a study published in the latest Proceedings of the
National Academy of Sciences, numerous fossil teeth found in the
Bugti Hills of central Pakistan were from three new anthropoids.
Anthropoids are the group scientists believe were our
world-travelling animal cousins, the primates from which humans
"The Oligocene period [30 to 25 million years ago] in south Asia
was so far totally undocumented palaeontologically," says lead
author Dr Laurent Marivaux.
"So, it is not surprising that the discovery of fossilised
animals from this period is totally new for science, and that
they [may] change or modify substantially our previous view on
mammal evolution, notably here, the evolutionary history of
"The evolutionary history of these old anthropoid lineages
represents the beginnings of the evolutionary history of
Marivaux and his team named the new anthropoids Bugtipithecus
inexpectans, Phileosimias kamali and Phileosimias brahuiorum.
They were tiny and somewhat similar to today's lemurs, says
Marivaux, a palaeontologist at the Institute of Evolutionary
Science at Montpellier II University in France.
Their small, underdeveloped teeth reveal the primates probably
ate insects and fruit. Climate records for this period suggest
that the animals lived in a warm, humid tropical rainforest.
Fossil remains for other animals indicate the primates shared
the Asian rainforest with more than 20 different species of
rodents, bats, carnivores, deer-like animals, pigs, a rhino-like
creature, called baluchitherium, and other primates.
Remains for later primates similar to the new anthropoids have
previously been found in China, Burma and Thailand. The newly
excavated teeth now indicate that anthropoids had a larger range
in Asia than thought, since the animals made their way to
Dr Christopher Beard, curator and head of the Section of
Vertebrate Paleontology at the Carnegie Museum of Natural
History in Pittsburgh, says he generally agrees with the new
"Together, the fossil anthropoid primates that are known from
China, Thailand, Myanmar and now Pakistan constitute an
impressive amount of data indicating that the 'higher primate'
lineage that today includes all monkeys, apes, and humans must
have originated in Asia, not in Africa as earlier scientists
believed," Beard says.
"[The new evidence indicates] early members of this [anthropoid
Asian group] made its way to Africa, where they continued to
evolve and diversify, eventually giving rise to living monkeys,
apes and humans."
Christopher Wills, professor of biological sciences at the
University of California, San Diego, agrees it was likely that
early anthropoid evolution did not just occur in Africa.
Wills says the evolution probably included "substantial
migrations over long distances, in and out of Africa perhaps".
Beard and Marivaux say the early anthropoids that stayed in Asia
continued to evolve too, but not in a direction that led to apes
Most experts say humans only emerged in Africa.
Ian Pitchford PhD CBiol MIBiol