
Two spectacular new hominid fossils found in a cave at Malapa in South Africa in 2008 and 2009 have been assigned to a new species,
Australopithecus sediba ('sediba' means 'wellspring' in the local seSotho language). Discovered by a team led by Lee Berger and Paul Dirks, it is claimed by them to be the best candidate yet for an immediate ancestor to the genus
Homo. The fossils are between 1.78 and 1.95 million years old, about the same date of the oldest
Homo erectus fossils.
The first fossil, MH1, found by Lee Berger's son Matthew, is an almost complete skull and partial skeleton of an 11 to 12 year old boy. The 2nd fossil, MH2, is a partial skeleton of an adult female, including some jaw fragments. The boy's brain has a typical australopithecine size of 420cc, compared to the smallest
Homo brain of 510cc. Both skeletons are small, about 130cm (4'3") tall.
Au. sediba is most similar to, and quite likely descended from,
Au. africanus. The upper limbs are long, and similar to other australopithecines. Many features of the hip, knee and ankle bones show it was bipedal, like other australopithecines, but the foot bones are still quite primitive. However Berger et al. list many other features of the skull, teeth, and pelvis in which it resembles early
Homo fossils.
The discoverers have suggested that
Au. sediba might be ancestral to either
Homo habilis or
Homo rudolfensis, or that it might be a closely related sister group to
Homo - not a direct ancestor, but a close cousin. As the authors admit, these two individuals existed after the earliest known
Homo fossils (at about 2.3 million years), so they can't be human ancestors. However, it's possible that the
sediba species had already existed for a few hundred thousand years and that early members of it could have been human ancestors.
Interestingly, prominent scientists quoted in the media have split fairly evenly on the question of whether
sediba should have been assigned to
Homo or
Australopithecus - Bill Kimbel, Don Johanson, Susan Anton and Colin Groves went for
Homo, while Meave Leakey, Tim White and Ron Clarke didn't. Some scientists have even suggested that it may be a late-surviving variant of
Au. africanus.
However, the authors argued that the overall body plan was australopithecine, and hence put it in that genus. This seems to be the conservative and safest plan; even if they are right in their claims about
sediba, the fossils do not seem out of place in
Australopithecus, whereas putting them in
Homo would have run the risk of needing to reclassify them later if they did not turn out to be very closely related to
Homo. It would also, as Chris Stringer pointed out in an interview, require "a major redefinition" of the genus
Homo.
In summary, it's an important discovery even though we don't yet know exactly how it fits into the family tree and what it means for human origins. Refreshingly, the discoverers have been fairly restrained in their claims about the fossil, and are keeping other options in mind.
The creationist organization Answers in Genesis
has already taken note of the fossil. One might have expected that such small, and small-brained, fossils would be dismissed as apes. A few years ago, I'm sure AIG would have done so unhesitatingly. But AIG has strongly backed the idea that the similarly-sized
Hobbit from Flores is a pathological human. Because of that, and probably also because some scientists have said
Au. sediba should have been classified as
Homo, AIG was surprisingly cautious. After referring to a quote by Berger that the small brain size of
sediba (an australopithecine feature) is similar to that of the Flores Hobbit, AIG says that:
Berger's comment suggests the Australopithecus sediba fossils may in fact be misclassified Homo individuals who were fully human.
and
Creationists must be cautious interpreting news like this.
But whatever happened to
this earlier claim by AIG:
When complete fossils are found, they are easy to assign clearly as either 'ape' or human, there are only 'ape-men' where imagination colored by belief in evolution is applied to fragmented bits and pieces.
What happened to it is that creationists have been slapped around by reality: there are too many cases where creationists have classified fossils differently, and even cases of creationists changing their mind about some fossils. In spite of having an almost complete skull of
sediba, AIG
still can't decide whether it's an ape or a human. If they can't tell if it's an ape or a human, they obviously can't rule out the possibility that it is an intermediate. The fact that they can't tell is strong evidence that it is intermediate, because modern apes and humans are extremely easy to distinguish.
Brian Thomas of the Institute for Creation Research
has also written about sediba. Unlike AIG however, ICR had no hesitation in calling it an ape. Thomas even disputes the claim that
sediba was bipedal, saying
... in neither A. ramidus' nor Au sediba's remains were found the relevant hip bones to even make such a determination!
Odd. MH1 has a good specimen of the os coxa bone, more commonly known as "the hip bone", which is, funnily enough, the "relevant hip bone" for diagnosing locomotion. And let's not forget that Berger et al. said that the hip, knee and ankle bones all show evidence of bipedality. I think the experts have a bit more credibility here than the ICR's science writer.
One last gripe: it was depressing to see how many newspaper headlines used the term "missing link". It's a misleading and meaningless term, as
Carl Zimmer explains well.
Update: See also this later Panda's Thumb blog entry by Nick Matzke:
Creationist vs. creationist on Homo habilis.
References
Australopithecus sediba: a new species of Homo-like Australopith from South Africa, by Berger et al. 2010. Science 328:195-204.
Yet Another "Missing Link", by Carl Zimmer
News to Note, April 10, 2010, by Answers in Genesis
A New Evolutionary Link?, by Brian Thomas, Institute for Creation Research
84 Comments
eric · 27 April 2010
MikeMa · 27 April 2010
Fascinating image of MH1 showing the actual bones superimposed over the speculative majority of missing stuff. I like jigsaw puzzles but my hat is off to the folks who created so much from so little. Well done.
I hope they find more and can piece together a more definitive lineage.
Chris · 27 April 2010
"In spite of having an almost complete skull of sediba, AIG still can’t decide whether it’s an ape or a human. The fact that they can’t tell is strong evidence that it is intermediate, because modern apes and humans are extremely easy to distinguish."
I don't think AIG's inability to distinguish fossils - these or any others - ever qualifies as "strong evidence."
ppb · 27 April 2010
MikeMa · 27 April 2010
AiG is not a scientific group but a political one. Their opinion on science is like asking George W Bush about the constitution. There is no connection.
wamba · 27 April 2010
Thomas even disputes the claim that sediba was bipedal, saying:
"Really, they didn't find any shoes!"
Graeme · 27 April 2010
How odd. I have read this post 10 minutes are returning from Maropeng at the Cradle of Humankind (http://www.maropeng.co.za/) where I saw the very same picture as in this post, but life-size, along with heaps of other hominid fossils and fossil replicas.
JohnW · 27 April 2010
afarensis, FCD · 27 April 2010
Sounds like the hobbit has freaked AIG out. Are they abandoning brain size as a criteria for membership in Homo?
MikeMa · 27 April 2010
stevaroni · 27 April 2010
e-dogg · 27 April 2010
RBH · 27 April 2010
John Kwok · 27 April 2010
John Kwok · 27 April 2010
Just to get back on topic, yes, that piece from Carl is an excellent summary as to what we ought to see with regards to the "shape" of the hominim family tree across the period from approximately 3.5 to 1.8 million years ago. At the very least, this new fossil merely illustrates not only that the australopith phylogenetic "bush" was wider than we thought, but does illuminate a bit more knowledge regarding how the earliest Homo hominims divulged from their australopith relatives.
As for the nonsense from AiG and ICR, I'll leave at that, since it's mendacious intellectual pornography that I have no desire to comment further on
Stanton · 27 April 2010
Henry J · 27 April 2010
This find just increases the number of gaps!!111!!!eleven!!!
DiscoveredJoys · 27 April 2010
Just a minor quibble "but the foot bones are still quite primitive" could be read as implying some directionality in evolution. "but the foot bones are more similar to earlier fossils" would have been better.
mplavcan · 27 April 2010
mplavcan · 27 April 2010
MikeMa · 27 April 2010
Wheels · 27 April 2010
Even if the mainstream news doesn't cover this accurately, or if anti-evolutionists still want to tow the party line and call it a "mere ape," I still get all giddy over finds like this. I love it when we find pieces of the puzzle that increase our knowledge of the natural world; it fills me with hope for our species.
Robin · 27 April 2010
Jim Foley · 27 April 2010
Jim Foley · 27 April 2010
Hansen · 27 April 2010
Reinard · 27 April 2010
AiG seems to be overly cautious about making any positive claims lately. They did the exact same thing with the Noah's Ark story. I guess they finally got burned one too many times. Perhaps they are capable of learning.
Robert Byers · 27 April 2010
i think AIG gave a intelligent and conservative responce.
First creationists are not studying these bits of bones.
So the only way to judge is from reports of how alike they are with humans or apes.
In fact there is a great sameness between people and apes in mere skeleton looks.
It probably is just apes of a type.
The clincher would be if a female was found in which it could be seen if the body had the configuration that would give pain at childbirth like our women.
Animals, apes, don't have pain for structural reasons.
Jim Foley · 27 April 2010
Stanton · 27 April 2010
Stanton · 27 April 2010
Thomas · 28 April 2010
Article seems like wishful thinking. AIG hasn't changed position.
AIG: When *complete* fossils are found, they are easy to assign clearly as either ‘ape’ or human...
PT: In spite of having an almost complete skull of sediba, AIG still can’t decide whether it’s an ape or a human.
I'd bet AIG doesn't have "an almost complete skull," or even seen more of it than the picture in the article.
AIG: The bones have been examined by only one group of scientists... Creationists, in particular, do not routinely have access to such finds until much time has passed...
hoary puccoon · 28 April 2010
According to Thomas, AIG says "the bones have been examined by only one group of scientists."
According to mplavcan, "the team is being very good at showing the fossils around."
Major discrepancy there.
Apparently, AIG has come up with their new position that they won't assign human or ape status until the fossil is "complete." Since even well-preserved skeletons like the Neanderthal of La Chappelle-aux-Saints are probably missing a few small pieces, that means AIG never has to choose at all, do they? Seems like a major retreat to me.
Stanton · 28 April 2010
DS · 28 April 2010
I don't really care what AIG or Byers think. Clearly this is an intermediate between ancestral apes and modern humans by any reasonable definition.
I also don't want this to degrade into another "pain of childbirth" fiasco. However, I would just like to point out in passing that in a recent National Geographic program, they documented attempts to reintroduce bison into wilderness areas. One scene showed a female who had complications with a delivery and died after a prolonged period of suffering. If Robert thinks that humans are the only animal that suffers during childbirth, or that this is somehow a species specific character, he should give it a try. Until then he should keep his ignorant opinions to himself.
James F · 28 April 2010
Thomas · 28 April 2010
Article seems like wishful thinking. AIG hasn't changed position.
AIG: When *complete* fossils are found, they are easy to assign clearly as either ‘ape’ or human...
PT: In spite of having an almost complete skull of sediba, AIG still can’t decide whether it’s an ape or a human.
I'd bet AIG doesn't have "an almost complete skull," or even seen more of it than the picture in the article.
AIG: The bones have been examined by only one group of scientists... Creationists, in particular, do not routinely have access to such finds until much time has passed...
John Vanko · 28 April 2010
No doubt AIG will claim they cannot distinguish between ape or human because they won't be given direct access to these bones.
If you follow AIG very much you will recall that they often bemoan the fact that 'evolutionist' scientists won't allow creationist 'scientists' to examine their fossils.
Why don't creationist 'scientists' go find their own hominid fossils? Why not do some real science instead of spending millions on a creationist museum? Why not find their own hominids and put the lie of evolution to rest once and for all? (And win the Nobel Prize for doing it!)
I'd like Ken Ham to answer that one. (Although I can guess the answer.)
John Kwok · 28 April 2010
John Kwok · 28 April 2010
Stanton · 28 April 2010
Helena Constantine · 28 April 2010
John Vanko :
...Why don’t creationist ‘scientists’ go find their own hominid fossils? Why not do some real science instead of spending millions on a creationist museum? Why not find their own hominids and put the lie of evolution to rest once and for all? (And win the Nobel Prize for doing it!...
I understand your frustration, but think how awful that would be. Suppose by some strange mischance they actually found an important fossil. Creationists by definition don't have the requisite scientific training, so all information about its context would be lost (they know its less than 6000 years old, so why use radiometric dating on the rock strata it was found in?). They wouldn't be able to identify it or properly publish it. They certainly wouldn't allow real scientists to examine it.
stevaroni · 28 April 2010
Keelyn · 28 April 2010
eric · 28 April 2010
John Kwok · 28 April 2010
raven · 29 April 2010
Alex H · 29 April 2010
You know, I actually don't mind Byer's ranting. He's so disconnected from reality that I find him funny, and unlike AIG or the No Discoveries Institute, he's got no ability to influence people.
raven · 29 April 2010
Frank J · 29 April 2010
hoary puccoon · 29 April 2010
Poor AIG-- trying to sell a radical theory without any evidence. Here's a tip. The Smithsonian website has a large collection of hominid fossils available for study online.
But if it's really true that those mean ol' scientists won't give AIG access to research materials-- then why on earth should we pay attention to anything AIG has to say about human origins, when they freely admit their conclusions are based on absolutely no data?
stevaroni · 29 April 2010
Dave Luckett · 29 April 2010
Jesse · 29 April 2010
Mike Elzinga · 29 April 2010
W. H. Heydt · 29 April 2010
In support of Mike Elzinga's point... Consider Forrest Mims (very) short job with _Scientific American_ and just *why* it was so short.
robert van bakel · 29 April 2010
As a very interested lay-person, and just looking at the bones shown on the given picture, I would assume the following:1.) The skull, jaw, and teeth, are well preserved, giving 'experts'(ie. people who actually study this stuff)significant information about diet, and relative intelligence, including insights into possible language abilities; perhaps. 2.)The elongated arm and shortened leg suggest intermediate characteristics between apes and hominids; but I'll let the people that understand anatomy interpret this for me, not being an expert myself you understand.3.)But most significantly, the hip-thigh joint which suggests upright locomotion, or so I am reliably informed by experts who study this every hour, of almost every day, of their lives, and dammit, I am actually persuaded.
Now, what does Mr Byers come up with? Sorry, but that ham sandwich has just got to be kicked in his nethers!
Dave Luckett · 30 April 2010
They have the femur, including its ball-joint, and the pronounced curve at the top that anchors the gluteus medius muscle. Most of the acetabulum is also evident. The angle of the ball with the neck of the femur is close to the human standard of 125 degrees. Separately these would strongly indicate upright bipedal walking, but together are quite definite. The icing on the cake would be a knee-joint.
Interestingly, this looks somewhat less gracile than A. afarensis, especially about the arms and shoulders, and this might support the conclusion of the discovery team, that this is a late Australopithecine, not ancestral to humans. That is, this is not a forebear, it's a cousin.
mplavcan · 30 April 2010
raven · 30 April 2010
stevaroni · 30 April 2010
Vince · 30 April 2010
CS Shelton · 30 April 2010
Congrats on not getting into it with the troll, folks... I know I am usually total troll-bait. It's hard to resist antagonism, but it helps in this case that it's so transparently a cry for attention. (Same off-topic subject that elicited several replies before? Really?)
On topic, nice post, Stevaroni. I dismissed the "god tricked you" theory of planted evidence so quick I hadn't noticed that obvious extension of it. The "false evidence" God or Satan or whoever planted must be ongoing...
When creationists try to pigeonhole these fossils into man or ape, what do we call it? Is there a category tag for it? It happens often enough.
Vince · 30 April 2010
Mike Elzinga · 30 April 2010
CS Shelton · 30 April 2010
Apehole? Nice one, Vince.
Hm... How about "He ain't monkey, He's my brother" ? Too long... Um, "ApeHomoSaysWhat?" no... I got nothing.
Vince · 30 April 2010
Jim Foley · 30 April 2010
John Kwok · 30 April 2010
This is a bit off topic, but I know of a major paleontological discovery which will be published soon. Can't say anything more about it since it is embargoed news until the scientific paper is published. Will be fascinating to see how - or whether will - the usual agitprop creo mendacious intellectual pornographers (e. g. Ham, Luskin, Nelson) will react once it is published (And no, it's not another australopithecine fossil.).
W. H. Heydt · 30 April 2010
raven · 1 May 2010
hoary puccoon · 1 May 2010
The very fact that people can do good work in agriculture, medicine, etc., while mindlessly reciting "the world is 6000 years old. Species are fixed," proves evolution is a fact.
True story: A member of a biblical-literalist church got the plumb job of managing a church-owned cattle ranch. Since he 'knew' evolution was 'just a theory' he 'knew' he could ignore breeding programs and save the church money by buying the cheapest bulls on the market. His boss, also a biblical literalist who supposedly didn't 'believe' in evolution, took one look and said, "Get your knife out and cut [i.e., castrate] those things. They won't even make good steers." But the manager was strong in his belief that evolution was 'just a theory.'
As a result, the ranch's calf weaning weights plummeted, the manager was fired and his boss hired a manager who denied evolution on Sunday morning, but treated it as fact all the rest of the week.
Evolution is a fact because even people who don't 'believe' in the 'theory' have to accept that it's true to get their jobs done.
John Kwok · 1 May 2010
For the very reason I gave. Am sure the creos will miss completely its significance (of which more will be known quite soon, trust me). Am eagerly awaiting whether they'll be as dense as they have been with this new hominid.
Frank J · 1 May 2010
Robert Byers · 2 May 2010
Dave Luckett · 2 May 2010
It's called "evidence", Byers. I know you don't understand the idea. Just as you can't understand the difference between expert evaluation of it and your own ignorance, prejudice and unreason.
Frank J · 2 May 2010
DS · 2 May 2010
Your contrariness comes easily. Indeed if its not just about “experts” then why not list points? First intelligence is not from skull size. There is no evidence that measuring heads determines intelligence, but if it is useful in distinguishing apes and humans. All they can do is speculate on intelligence by how close the head size is to people, which is plenty good enough since intelligence is not the issue. Many historically did it with people too by the way, which is irrelevant. Gibberish. If legs/arms are widely not like people then they are just apes of a type, even though they have combinations of characters that are distinctly human. I don’t know about the hip/thigh thing. However it shouldn’t just suggest but determine if a creature is upright. By the way if so then by evolutionists position the women should be having pain at birth like ours and unlike apes, which is also completely irrelevant, since this is not considered to be a species characteristic by anyone. Drawing such great conclusions on a few skeletons is poor research, so it is a good thing that we have lots of skeletons of many different intermediates. Creationists could do better as usual, but as usual they don't do anything but whine and complain.
mplavcan · 2 May 2010
harold · 2 May 2010
John Kwok · 2 May 2010
Alex H · 3 May 2010
Guys, PLEASE go to a different forum for political discussions.
notlucy · 23 June 2010
MrG · 23 June 2010