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Discoverer of “Lucy” raises questions about Australopithecus sediba, the new human species from South Africa

The views expressed are those of the author and are not necessarily those of Scientific American.


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By now you’ve probably heard of Australopithecus sediba, the 1.95-million-year-old human species that made news on April 8. In a nutshell, researchers have found two beautifully preserved partial skeletons that they say represent a previously unknown member of the human family–one that may have given rise to our genus, Homo. You can read my story on the find here.

There’s a lot to talk about with this discovery, so I thought I’d supplement the story with some tidbits from the cutting room floor and material that came in after my deadline.

First, some tidbits:

  • Lead investigator Lee Berger’s nine-year-old son Matthew spotted the first A. sediba fossil–a collar bone that turned out to be from a juvenile individual around Matthew’s age. Matthew was originally listed as a co-author on the Science paper describing the fossils, but the reviewers of the paper rejected that idea, according to a news story that accompanied the technical reports in the journal.
  • The skeletons don’t have nicknames (a la Lucy) yet, because a contest is planned to allow the children of South Africa to come up with them.
  • When asked during a press teleconference whether he had found any tools at the site, Berger said he had not commenced formal excavation of the site and so did not want to talk about artifactual remains. He noted that the presence of tools would have enormous ramifications and that he would want to have substantial evidence before commenting on that. When pressed for more information by another reporter, he said he was not willing to comment on the presence of artifacts at this time. (The reason why tools would be such a big deal is that A. sediba‘s brain was really small–about a third as large as ours. Also, all the toolmakers on record belong to the genus Homo, not Australopithecus.)
  • You may have wondered why none of the media stories have included an illustration of what A. sediba looked like in life. According to Berger, such an effort is under way and before long we will see a reconstructed face. He said he thinks it will look like that of Homo erectus, but paired with a tiny brain case.

 

Lee Berger with Australopithecus sediba skull

With regard to that last point about A. sediba’s small cranium, this photo of Lee Berger holding the skull of the juvenile male specimen gives a sense of how tiny it is. Granted, it’s a juvenile (the adult female skeleton does not include a skull, although the discovery team expects to find that with further excavation), but the researchers say it had probably already attained at least 95 percent of adult brain size.The cranial capacity of this fellow is an estimated 420 to 450 cubic centimeters. In contrast, we modern humans have brains that typically range from about 1,200 to 1,600 cubic centimeters.

 

As I mentioned in the news story, what’s really striking about A. sediba is its mix of primitive and advanced traits. Here’s an image of the new fossils, superimposed over an illustration of an A. africanus skeleton (Berger and his colleagues argue that A. sediba is descended from A. africanus.) A list of representative primitive and advanced characteristics follows below.

 

Australopithecus sediba skeletons

 

PRIMITIVE TRAITS

  • Long arms (comparable to an orangutan’s)
  • Small brain case
  • Small body

DERIVED TRAITS

  • Long legs
  • Robust pelvis
  • Flat face with projecting nose
  • Small teeth

Lastly, here’s another perspective on A. sediba, from paleoanthropologist Donald Johanson, discoverer of the Lucy skeleton (full disclosure: I co-wrote a book with Johanson called Lucy’s Legacy: The Quest for Human Origins). He e-mailed the following comments, which I received after my news story had already been published:

"The South African finds from Malapa are most interesting, but I find it curious that the authors point to so many anatomical features that indicate that the finds belong to our genus, Homo, yet they place it in Australopithecus, so I think they missed the boat here. Finding 1.8-million-year-old Homo in southern Africa is news-worthy since previous traces have been fragmentary and controversial.   

Additionally, I do not see these fossils as evolving from Australopithecus africanus, which I believe gave rise to A. robustus in South Africa. The specimens from Malapa are not the ancestor to later all Homo as the authors believe, since we have evidence of Homo in eastern Africa at 2.33 million years. My team found an upper jaw of this age in the younger sediments at Hadar where Lucy was found, and this palate represents the oldest anatomical evidence, thus far, for our genus. It is probably best attributed to Homo habilis. Let us not forget that the Turkana Boy is about 1.8 million years old and is without doubt Homo and is attributed to Homo ergaster.  

The Malapa [hominids], with so many Homo features but with relatively short limbs, resemble Olduvai Hominid 62 which we found in the mid-80s. Although fragmentary, OH 62 does have relatively shorter legs and longer arms, like earlier Australopithecus, and the appearance in the fossil record of a more modern body built, as in the Turkana Boy, comes later. However the Olduvai material, OH 62 and several other specimens, are attributed to Homo on the basis of diagnostic features in the teeth, jaws and cranium. Some scholars have suggested we place H. habilis into the genus Australopithecus and until there is a modern body build Homo should not be used as the genus for these fossils.

It is also rather possible that Homo, like Australopithecus underwent a diversification (adaptive radiation) resulting in several different species, this would not be unusual. However, within the greater framework of Australopithecus and Homo, I believe emphasis should be placed on the diagnostic anatomy of the teeth, jaws and cranium…so, I would continue to use Homo for habilis, and for these new specimens from Malapa. Until a more comprehensive comparative study is undertaken (I know other specimens have been recovered from the site), the relationship between the Malapa material and Homo in eastern Africa is not very clear. I would not be surprised if the Malapa material represents a newly recognized species of Homo.

The South African finds about a half a million years younger are probably descendents of the eastern Africa Homo.   500,000 years is a long time and Homo could easily have migrated from eastern to southern Africa in that time.  

There are two partial skeletons, one a female and the other a male. The skull of the male is refreshingly complete and should be attributed to Homo. Just after Lee found the first hominids at Malapa, he invited me to see the material at Witswatersrand. The mandible is lightly built, not very deep or thick resembling Homo. The first and second permanent molars are erupted and there is little occlusal wear, suggesting a diet quite different from Australopithecus. In Australopithecus, by the time the second molar erupts the first shows rather heave wear. Also, the teeth are small in size, like in Homo, and unlike Australopithecus.

We have a very comprehensive understanding of the dating, diversity and relationships between the species of Australopithecus, but we know relatively little about the origins of our own genus, thus anything found that represents early Homo is potentially of some importance.  I think these finds will re-focus attention on the South African fossil sites and strengthen the importance of these sites for a more complete understanding of the human family tree."

 

Images: Photo courtesy of Wits University; skeletons courtesy of Science/AAAS

 

 

 





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  1. 1. jtdwyer 11:46 pm 04/9/2010

    The perceived importance of a new hominid find is certainly enhanced if it is found to be one of our direct progenitors. Meanwhile, there are an unknown number of hominid ‘dead ends’ that are not nearly as newsworthy. This must place a great deal of pressure on discoverers, who most often seem understandably enthusiastic about the import of their find. On the other hand, prior discoverers of important finds tend to be more skeptical…

    Link to this
  2. 2. doug l 8:01 am 04/10/2010

    Very nice summation of what’s generally known along with interesting speculation and the reasons behind it. Looking forward to more of this writer’s insights regarding these particular fossils and what seems like a sure bet to find more in the Malapa site’s deposits and others in the region. Also very tantalizing references to evidence of the presence of tools.

    Link to this
  3. 3. lowndesw 8:48 am 04/10/2010

    THANK YOU, Kate Wong, for a very interesting, well written article, especially because it is a follow-up or supplement to a previous interesting, well written article. THIS is an excellent example of why I and many others enjoy and subscribe to SciAm: clear, no-hype writing, excellent images, list of contrasts, comments by other authorities with other perspectives.

    I agree with jtdwyer’s, too.

    Link to this
  4. 4. tharriss 10:29 am 04/10/2010

    What woudn’t "fool you" jorgipogi? Is there any evidence that could ever convince you of anything? Just curious.

    Link to this
  5. 5. jtdwyer 2:45 pm 04/10/2010

    jorgipogi – If that’s true, you’ve got to admit the fake skeleton technology is now just as good as the real stuff…

    Link to this
  6. 6. jmelhus 9:24 pm 04/10/2010

    You are right SciCat, I’m not a scientist, but I am not a fool by any means. If you want to see some scientists that share my views on evolution please give this website a look. http://www.rae.org/darwinskeptics.html
    God Bless SciCat and I apologize if I offended you with my comments.

    Link to this
  7. 7. mikedave 9:52 pm 04/10/2010

    I always feel so sorry for people like this, so dumb and blind. Wake up, pull your nose out of your bible; it is just a bunch of crap written by Bronze Age goat herders, mistranslated and miscopied into complete gibberish over the years. To reject evolution is to reject basic science in every disciple. It is to reject basic science proven repeatedly in science classrooms everywhere. It is to reject experiments Ive done myself, do you think Im lying. Do you think everyone with a basic education is lying? Is it some huge conspiracy theory? Or is it, maybe, more likely that that you have been taught a bunch of BS from a book of BS.

    Link to this
  8. 8. mikedave 9:54 pm 04/10/2010

    jorgipogi & jmelhus

    I always feel so sorry for people like this, so dumb and blind. Wake up, pull your nose out of your bible; it is just a bunch of crap written by Bronze Age goat herders, mistranslated and miscopied into complete gibberish over the years. To reject evolution is to reject basic science in every disciple. It is to reject basic science proven repeatedly in science classrooms everywhere. It is to reject experiments I’ve done myself, do you think I’m lying. Do you think everyone with a basic education is lying? Is it some huge conspiracy theory? Or is it, maybe, more likely that that you have been taught a bunch of BS from a book of BS.

    Link to this
  9. 9. buzzi bee 10:59 pm 04/10/2010

    jorgepogi
    Please save us the search for the truth about the A. sadiba fossils. Scientists researched and learned the crystal skulls were fakes, as was the case with other fake fossils or artifacts. Please inform us of the fake information for sadiba so we can move on to real fossils. We want the truth, so be kind and relate the details to us. The credit may be all yours.
    I was so excited about this sadiba find, but your proof for a big lie will end that for me. Thanks.
    busy bee

    Link to this
  10. 10. hotblack 1:06 am 04/11/2010

    "My great great great… grandparents were not primates or anything near them. In fact they were human beings just like myself."

    Whew, what a relief! I’m so glad we have you to remember the beginning of time. We’ve all been stuck with having to devote lifetimes of study in an effort to glean a detail or two out of this gigantic mountain of physical evidence, the genetic record, the fossil record, the geological record… Thank Mithra we can knock all that difficult work off and simply have you let us in on the truth. I look forward to seeing how your story resolves all this evidence without any dynamism at all! So exciting! Who would have guessed your pagan-egyptian religious amalgam was right all along. Lucky for you, being a devotee. And lucky that Constantine wasn’t just another opportunistic politician as indicated by everything he wrote, but actually divinely inspired when he picked & chose the Council of Nicea and fused all the clashing cults of rome into one.

    Link to this
  11. 11. G.Wiz 4:56 am 04/11/2010

    So jmelhus – if your grandparents (& you) aren’t primates, how do you explain the fact that you share over 99% of your critical DNA sites with a chimp?

    http://www.newscientist.com/article/dn3744

    Link to this
  12. 12. tulcak 6:48 am 04/11/2010

    don’t bother discussing anything with these nut cases who talk about god and fake fossils. they are able to make themselves blind and deaf to all of reality…

    Link to this
  13. 13. jmelhus 6:48 am 04/11/2010

    G. Wiz- I am not arguing with science, and agree that yes humans share somewhere between 95-99% of their DNA with chimpanzees. But also noteworthy here is the fact that humans share 50% of their DNA with bananas. Also, humans share 60% of their DNA with fruit flies. With sharing this much DNA with bananas/fruit flies you would sure think we would have some physical similarities. If evolution is true, then you must claim common ancestry with the banana and fruit fly as well. God Bless

    Link to this
  14. 14. tulcak 6:52 am 04/11/2010

    we should look like bananas and fruit flies? wow. ok, with that logic, we should all look like stars because that is where ultimately the more complex elements are made. and with which we are composed of.

    Link to this
  15. 15. jtdwyer 5:15 pm 04/11/2010

    jmelhus – You have a point there, but I don’t think it’s valid. As I understand, much of the DNA in an organism’s cells do not produce distinguishing characteristics, but regulate common cellular functions. Much of the DNA determines how how other DNA sequences are decoded. In fact, we do share some low level cellular functions with other complex organisms such as fruit flies and bananas, I suppose.

    The fact that bananas and me both require that some material passes into cellular membrane while others do not has little affect on my ability to identify an inadequately constructed argument. Apparently, some people do not share that ability, making them somewhat more similar to bananas than I am.

    Link to this
  16. 16. mihondo 7:18 pm 04/11/2010

    It seems that differentiating various traits into primitive and evolved assumes that the development of traits happens only in one direction. There was a comment that the ancestral remains of other apes have not been found. Maybe they have been. We seem to be fixated on assigning our own lineage and not considering that perhaps some of these could have developed into the other apes of modern time.

    Even with genetic information (which really is the primary way that we can connect evolutionary dots), gazing into the deep past only gives us momentary glimpses over a vast periods of time. I think it highly probably that our current hypothesis of lineage have little to do with reality. For sure some set of evolutionary steps got us here … but I think it unlikely we we really know what those steps really were.

    Link to this
  17. 17. jtdwyer 7:25 pm 04/11/2010

    jmelhus – Fine. I respect you, too. Go with God, but go.

    Link to this
  18. 18. blindboy 5:19 am 04/12/2010

    Of course evolution is wrong. God just created all that evidence to confuse us!

    Link to this
  19. 19. blindboy 5:43 am 04/12/2010

    "I believe that I was fearfully and wonderfully made by the Lord Jesus Christ. "

    So he went back in time to make Adam and Eve? Since according to your text book they existed long before JC himself was born. Or is it just you, and not the rest of the human race, who he made? Or are you theologically and chronologically, as well as scientifically, challenged?

    Also please explain exactly what parts of the atomic theory you believe in, since the model of the atom that we use to explain nuclear energy is the same as the one that we use to date fossil material. If you accept that nuclear energy actually exists you need to come up with some pretty fancy footwork to disbelieve in isotope dating! But hey give it a try, we need a laugh!

    More seriously, trying to fit new fossils into the already confusing hominid family tree is always going to produce disagreement. I think we have a "lumpers" vs "splitters" debate beginning here. Lumpers try to place new discoveries into established species, splitters try to create new ones. The outcome of these debates is probably less important than the debates themselves since reclassification can always occur.
    The really important thing is that the gradual accumulation of evidence has already given us a good overview of human evolution from the Miocene apes, through the Austalopithecines, to early Homo and on to H. sapiens sapiens. Yes, there is a huge amount of detail to fill in but the achievement of this much already counts as one of science’s greatest triumphs.

    Link to this
  20. 20. jmelhus 8:08 am 04/12/2010

    In the beginning was the Word, and the Word was with God, and the Word was God. The same was in the beginning with God. All things were made by him; and without him was not any thing made that was made. In him was life; and the life was the light of men. And the light shineth in darkness; and the darkness comprehended it not. John 1:1-5

    Christ is the visible image of the invisible God. He existed before anything was created and is supreme over all creation.Colossians 1:15

    http://www.answersingenesis.org/media/video/ondemand/creation_confirms_bible/creation-confirms-bible

    God Bless

    Link to this
  21. 21. jtdwyer 12:04 pm 04/12/2010

    jmelhus – If I had more energy and wasn’t dying I’d go to your site and preach the gospel of evolution. You’ve got no more right to come here talking creationism than I would showing up at your church and disrupting the proceedings with polite questions about Genesis. I am also more considerate of others than that.

    The fact that I was expelled from my Sunday school class in 1960 for asking the polite questions of a 10 year old who had heard of evolution makes this issue somewhat personal with me.

    I do respect your right to practice your religion, but I have to say that you are far more obnoxious than most. For your sake I hope your faith is stronger than your arguments. You too may be called upon soon.

    Link to this
  22. 22. jmelhus 2:37 pm 04/12/2010

    I know that I am obnoxious, nuts, and even related to trolls apparently. All I wanted to do was to share my views and people ridiculed me for doing so. I thought science was open to debate, but I guess that I was wrong. This is my last post and then this nut case will hit the road. If evolution is true, then show me where to find the answer to this …Which came first, the chicken or the egg? If it was the chicken, then how did it reproduce? And if it was the egg likewise.

    The Bible teaches that God created two of every living creature and that they reproduce after their own kind.

    jtdwyer I am sorry to hear about your experience in Sunday school when you were younger. Please don’t let what happened in that church keep you from knowing and seeking God personally. I will keep you in my prayers.

    I apologize again for upsetting or offending anyone here with my comments. I will not post anymore. If anyone wants to make any further remarks regarding my posts or views you can email me at jared_melhus@hotmail.com

    God Bless

    Link to this
  23. 23. Grasshopper1 6:48 pm 04/12/2010

    Everyone:

    jmelhus was just trying to share his views. I know this site was the wrong place to share them, but he is not nuts, obnoxious, and certainly not "related to trolls".

    Though most of the commenters here (including myself) disagree with his views, we must acknowledge that people have different beliefs, and we must be tolerant of other people’s beliefs.

    Link to this
  24. 24. Piltdownman was innocent? 4:21 am 04/13/2010

    Scicat says:
    "Why do you come to a science site if you don’t believe in Science? And, yes, disbelieving evolution does mean that you do not believe in Science, as evolution is strongly supported by evidence from many scientific disciplines."

    Evolution equals CHANGE equals science. But the …..
    Theory of Evolution equals Science fiction, zero evidence & zero observations.

    Link to this
  25. 25. jtdwyer 2:30 am 04/14/2010

    Apparently, if Jesus were an evolutionary biologist, he would visit religious sites, posting blog entries explaining how Genesis is incorrect, how it simply represents a compilation of then current, regional, origin myths, based primarily on the cultural transition from roaming hunter-gatherer societies to settled agricultural based communal tribes.

    But I have more respect for others’ personal religious views than to impose on them like that. Perhaps I should not continue to be so considerate?

    Link to this
  26. 26. Piltdownman was innocent? 4:23 am 04/15/2010

    jtdwyer says:

    "Apparently, if Jesus were an evolutionary biologist, he would visit religious sites, posting blog entries explaining how Genesis is incorrect, how it simply represents a compilation of then current, regional, origin myths, based primarily on the cultural transition from roaming hunter-gatherer societies to settled agricultural based communal tribes.”

    Jtdwyer is a bit late. Jesus Christ when on our planet Earth 2,000 years ago, confirmed the Genesis account as stated in the Bible. Please see Matthew 19: 4-5 where Jesus quoted from Genesis 1:27 & 2:24.

    Link to this
  27. 27. bucketofsquid 4:08 pm 04/15/2010

    As a Christian with more than 1 brain cell I easily recognized that the Bible is not literally true. The old testament radically disagrees with the new testament on a huge range of topics. The inclusion of Jewish resistance literature written by a non-Christian is a pretty good indicator (Revelations anyone?).

    As mentioned by a prior poster – Constantine was a pagan politician concerned with the divisiveness of multiple religions and wanted to unify an empire. There is no real evidence that he actually converted – only the word of others after he died. There is nothing to show that a death bed conversion has any validity.

    If God had provided a full accounting of creating the world, in minute detail, how many illiterate goat herders would have remembered over many generations until literacy occurred and the story could be written down?

    I find it significant that at the time of Constantine most Christians followed the teachings of Arias and yet his beliefs were discarded from the orthodox/catholic versions.

    Getting back to the actual topic of this story:
    I would require a lot more evidence before forming any opinion on this ancient creature other than "ooh icky! It’s a dead thing!"

    Link to this
  28. 28. Scico 7:58 pm 04/16/2010

    Why do almost all the comment sections on this website end up as an evolution/creation arguement? This is a science magazine. Leave us science people alone to burn in hell with Darwin and Galileo. It is our choice. Let me direct the creationists to the National Enquirer website, it will be more suited to your mentality.
    Back to the article: yes this is an exciting find and should be debated. This is science, we don’t find answers only more questions.

    Link to this
  29. 29. Piltdownman was innocent? 3:48 am 04/17/2010
    Link to this
  30. 30. Piltdownman was innocent? 3:49 am 04/17/2010

    Scico argues:

    “Why do almost all the comment sections on this website end up as an evolution/creation arguement? This is a science magazine. Leave us science people alone to burn in hell with Darwin and Galileo. It is our choice.”

    You have two choices. You believe God is the creator of the Universe, planet Earth and manKIND or you believe NOBODY created everything from nothing with a lot of luck & chance.

    Australopithecus sediba gives the game away about who he is …
    “PRIMITIVE TRAITS
    *Long arms (comparable to an orangutan’s)”

    Link to this
  31. 31. Piltdownman was innocent? 4:08 am 04/17/2010

    bucketofsquid argues:

    ++ “If God had provided a full accounting of creating the world, in minute detail, how many illiterate goat herders would have remembered over many generations until literacy occurred and the story could be written down?
    I find it significant that at the time of Constantine most Christians followed the teachings of Arias and yet his beliefs were discarded from the orthodox/catholic versions.”

    I find it strange that you are an alleged Christian and fail to remember the basic truth that God inspired the many writers of the Bible who came from all walks of life. Thus it was not left to human memory. You condemn Moses (the writer of Genesis) to being a goat herder which shows further evidence that you are not a Christian, because you fail to remember that until he was 80 years of age Moses was a Prince of Egypt. Also, David became a King.

    Your remark with reference to Constantine is correct, but the truth of all things remains in the Bible.

    Link to this

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