Study: Human Ancestors Originated in Asia
By Jennifer Viegas
Discovery News, May 31, 2005
Three newly discovered primate species that lived 30 million years ago suggest that our first ancestors originated in Asia and not in Africa, challenging the well-known "Out of Africa" theory about human evolution.
The actuality 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 traveled both in and out of Africa.
According to a study published in this week's Proceedings of the National Academy of Sciences, numerous fossil teeth for the three new anthropoids were found in the Bugti Hills of central Pakistan.
Scientists believe our world-traveling animal cousins were anthropoids, which means "apes" and refers to the group of primates from which humans evolved.
"The Oligocene period (30-25 million years ago) in South Asia was so far totally undocumented paleontologically," said Laurent Marivaux, lead author of the paper.
"So, it is not surprising that the discovery of fossilized 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 anthropoid primates."
He added, "The evolutionary history of these old anthropoid lineages represents the beginnings of the evolutionary history of humans."
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, according to Marivaux, who is a paleontologist at the Institute of Evolutionary Science at Montpellier II University in France.
Their small, underdeveloped teeth reveal that 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 previously were 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 Pakistan.
Christopher Beard, curator and head of the Section of Vertebrate Paleontology at the Carnegie Museum of Natural History in Pittsburgh, told Discovery News that he generally agreed with the new conclusions.
"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 said.
He added that the new evidence, to him, indicated that "an early member 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, agreed that early anthropoid evolution likely did not just occur in Africa.
Wills told Discovery News that the evolution probably included "substantial migrations over long distances, in and out of Africa perhaps."
Beard and Marivaux said the early anthropoids that stayed in Asia continued to evolve too, but not in a direction that led to apes and humans. The consensus among most experts is that humans only emerged in Africa.