A famous “ancestor” may be ousted from the human family

Apr 24, 2017

By Ann Gibbons

NEW ORLEANS, LOUISIANA—A remarkably complete skeleton introduced in 2010 as “the best candidate” for the immediate ancestor of our genus Homo may just be a pretender. Instead of belonging to the human lineage, the new species of Australopithecus sediba is more closely related to other hominins from South Africa that are on a side branch of the human family tree, according to a new analysis of the fossil presented here last week at the annual meeting of the American Association of Physical Anthropologists.
When fossils from several individuals’ skeletons were found in a collapsed cave in Malapa, South Africa, in 2008, their discoverer, paleoanthropologist Lee Berger of the University of the Witwatersrand, noted that they helped fill a key gap in the fossil record 2 million to 3 million years ago when some upright-walking australopithecine evolved into the earliest member of our genus, Homo. But the oldest Homo fossils, at 2.4 million to 2.9 million years, are scrappy, and a half dozen more primitive hominins may have been walking around Africa at roughly the right time to be the ancestor. Researchers have hotly debated whether their direct ancestor was the famous 3.2-million-year-old fossil Lucy and her kind, Australopithecus afarensis from Ethiopia, or another australopithecine.
With its fossils dated to 1.98 million years ago, Au. sediba is too young to be directly ancestral to all members of the genus Homo. But Berger and his colleagues proposed in 2010, and again in 2013 in six papers in Science, that given the many humanlike traits in Au. sediba’s face, teeth, and body, the Malapa fossils were a better candidate than Lucy or other East African fossils to be ancestral to Homo erectus, a direct human ancestor that appeared 1.8 million years ago.

Continue reading by clicking the name of the source below.

2 comments on “A famous “ancestor” may be ousted from the human family

  • A much more recent human ancestor has now been found in Morocco which may challenge previously held views.

    http://www.bbc.co.uk/news/science-environment-40194150

    The idea that modern people evolved in a single “cradle of humanity” in East Africa some 200,000 years ago is no longer tenable, new research suggests.

    Fossils of five early humans have been found in North Africa that show Homo sapiens emerged at least 100,000 years earlier than previously recognised.

    It suggests that our species evolved all across the continent, the scientists involved say.

    Their work is published in the journal Nature.

    Prof Hublin was speaking at a news conference at the College de France in Paris, where he proudly showed journalists casts of the fossil remains his team has excavated at a site in Jebel Irhoud in Morocco. The specimens include skulls, teeth, and long bones.

    Earlier finds from the same site in the 1960s had been dated to be 40,000 years old and ascribed to an African form of Neanderthal, a close evolutionary cousin of Homo sapiens.

    But Prof Hublin was always troubled by that initial interpretation, and when he joined the MPI he began reassessing Jebel Irhoud. And more than 10 years later he is now presenting new evidence that tells a very different story.

    The latest material has been dated by hi-tech methods to be between 300,000 and 350,000 years old. And the skull form is almost identical to modern humans.

    The few significant differences are seen in a slightly more prominent brow line and smaller brain cavity.

    Prof Hublin’s excavation has further revealed that these ancient people had employed stone tools and had learned how to make and control fire. So, not only did they look like Homo sapiens, they acted like them as well.

    Until now, the earliest fossils of our kind were from Ethiopia (from a site known as Omo Kibish) in eastern Africa and were dated to be approximately 195,000 years old.

    “We now have to modify the vision of how the first modern humans emerged,” Prof Hublin told me with an impish grin.

    Before our species evolved there were many different types of primitive human species, each of which looked different and had its own strengths and weaknesses. And these various species of human, just like other animals, evolved and changed their appearance gradually, with just the occasional spurt. They did this over hundreds of thousands of years.

    Jebel Irhoud is typical of many archaeological sites across Africa that date back 300,000 years. Many of these locations have similar tools and evidence for the use of fire. What they do not have is any fossil remains.

    Because most experts have worked on the assumption that our species did not emerge until 200,000 years ago, it was natural to think therefore that these other sites were occupied by an older, different species of human. But the Jebel Irhoud finds now make it possible that it was actually Homo sapiens that left the tool and fire evidence in these places.

    “We are not trying to say that the origin of our species was in Morocco – rather that the Jebel Irhoud discoveries show that we know that [these type of sites] were found all across Africa 300,000 years ago,” said MPI team member Dr Shannon McPhearon.

    Prof Chris Stringer from the Natural History Museum in London, UK, was not involved in the research. He told BBC News: “This shows that there are multiple places in Africa where Homo sapiens was emerging. We need to get away from this idea that there was a single ‘cradle’.”

    And he raises the possibility that Homo sapiens may even have existed outside of Africa at the same time: “We have fossils from Israel that are probably the same age and they show what could be described as proto-Homo sapiens features.”



    Report abuse

Leave a Reply

View our comment policy.