Sterkfontein again: the slow reconstruction of an Australopithecine

[Jacques Cinq-Mars]

This, from the BBC, at: http://news.bbc.co.uk/1/hi/sci/tech/2709797.stm

On the recent reconstruction of  3.5 my Australopithecus individual (by R. Clarke) who wants to distance itself from ancestral chimps.

It would appear, therefore, that the strong opposable thumb evolved in the human ancestral stock for grasping branches. Then, in the mainly terrestrial subsequent descendants in the form of Homo, it was to prove useful for tool-making and manipulation.

"The suggestion in reconstructions and in the scientific literature that human ancestors were transformed into an upright position from a knuckle-walking ancestor is not supported by this new and important addition to the fossil record.

People having full access to the most recent issue of the South African Journal of Science <http://www.nrf.ac.za/sajs/index.stm> will be in a position to tell us more about this.

Jacques Cinq-Mars

[Daryl Habel]

This, from the BBC, at: http://news.bbc.co.uk/1/hi/sci/tech/2709797.stm

On the recent reconstruction of  3.5 my Australopithecus individual (by R. Clarke) who wants to distance itself from ancestral chimps.

It would appear, therefore, that the strong opposable thumb evolved in the human ancestral stock for grasping branches. Then, in the mainly terrestrial subsequent descendants in the form of Homo, it was to prove useful for tool-making and manipulation.

"The suggestion in reconstructions and in the scientific literature that human ancestors were transformed into an upright position from a knuckle-walking ancestor is not supported by this new and important addition to the fossil record.

People having full access to the most recent issue of the South African Journal of Science <http://www.nrf.ac.za/sajs/index.stm> will be in a position to tell us more about this.

Jacques Cinq-Mars

Ron Clarke probably has something interesting to say in the new issue of South African Journal of Science, but I doubt if BBC reporters would understand it.  The SAJS website at the moment still promotes the "current issue" as that of three months ago.  On the other hand, SAJS has made free pdf's available of previous papers concerning this 3.5 million year old skeleton (see icons at the right hand side of the home page:

http://www.nrf.ac.za/sajs/index.stm

so it would pay to keep watching to see what appears on the website when they update it to the new "current issue".

It would seem that they have managed to extract some of the skeleton ("pelvis, upper leg, ribs and backbone" according to BBC), enough so that they can say that this 3.5 My-old  Australopithecus (presumed) was bipedal and did not knuckle-walk like a chimp (Duh!!!).

Apparently the main argument Clarke will put forth will be that the ape/human last common ancestor was also not a knuckle-walker, based on this 3.5 million-year-old skeleton's limb proportions and hand/foot morphology (having a "powerful thumb and a vice-like grip"). The issue of whether the ape/human LCA was a knuckle-walker or not has been argued since forever, and if evidence of a powerful gripping thumb in a skeleton approximately 3 million years evolved from the LCA is the argument's strong point,  I doubt whatever Clarke (or Robin Crampton) has to say will put the issue to rest as decided.

Still, it's nice to hear that they've made some progress removing the skeleton from the matrix, and whatever the paper has to say, I'm sure it will be both interesting and informative.

Dar

(modified 3/14/2003 only with correction spelling of Clarke)

[Jacques Cinq-Mars]

This, from the BBC, at: http://news.bbc.co.uk/1/hi/sci/tech/2709797.stm

On the recent reconstruction of  3.5 my Australopithecus individual (by R. Clarke) who wants to distance itself from ancestral chimps.

It would appear, therefore, that the strong opposable thumb evolved in the human ancestral stock for grasping branches. Then, in the mainly terrestrial subsequent descendants in the form of Homo, it was to prove useful for tool-making and manipulation.

"The suggestion in reconstructions and in the scientific literature that human ancestors were transformed into an upright position from a knuckle-walking ancestor is not supported by this new and important addition to the fossil record.

People having full access to the most recent issue of the South African Journal of Science <http://www.nrf.ac.za/sajs/index.stm> will be in a position to tell us more about this.

Jacques Cinq-Mars

Ron Clark probably has something interesting to say in the new issue of South African Journal of Science, but I doubt if BBC reporters would understand it.  The SAJS website at the moment still promotes the "current issue" as that of three months ago.  On the other hand, SAJS has made free pdf's available of previous papers concerning this 3.5 million year old skeleton (see icons at the right hand side of the home page:

http://www.nrf.ac.za/sajs/index.stm

so it would pay to keep watching to see what appears on the website when they update it to the new "current issue".

It would seem that they have managed to extract some of the skeleton ("pelvis, upper leg, ribs and backbone" according to BBC), enough so that they can say that this 3.5 My-old  Australopithecus (presumed) was bipedal and did not knuckle-walk like a chimp (Duh!!!).

Apparently the main argument Clark will put forth will be that the ape/human last common ancestor was also not a knuckle-walker, based on this 3.5 million-year-old skeleton's limb proportions and hand/foot morphology (having a "powerful thumb and a vice-like grip"). The issue of whether the ape/human LCA was a knuckle-walker or not has been argued since forever, and if evidence of a powerful gripping thumb in a skeleton approximately 3 million years evolved from the LCA is the argument's strong point,  I doubt whatever Clark (or Robin Crampton) has to say will put the issue to rest as decided.

Still, it's nice to hear that they've made some progress removing the skeleton from the matrix, and whatever the paper has to say, I'm sure it will be both interesting and informative.
Dar

This, from the BBC, at: http://news.bbc.co.uk/1/hi/sci/tech/2709797.stm

On the recent reconstruction of  3.5 my Australopithecus individual (by R. Clarke) who wants to distance itself from ancestral chimps.

It would appear, therefore, that the strong opposable thumb evolved in the human ancestral stock for grasping branches. Then, in the mainly terrestrial subsequent descendants in the form of Homo, it was to prove useful for tool-making and manipulation.

"The suggestion in reconstructions and in the scientific literature that human ancestors were transformed into an upright position from a knuckle-walking ancestor is not supported by this new and important addition to the fossil record.

People having full access to the most recent issue of the South African Journal of Science <http://www.nrf.ac.za/sajs/index.stm> will be in a position to tell us more about this.

Jacques Cinq-Mars

Ron Clark probably has something interesting to say in the new issue of South African Journal of Science, but I doubt if BBC reporters would understand it.  The SAJS website at the moment still promotes the "current issue" as that of three months ago.  On the other hand, SAJS has made free pdf's available of previous papers concerning this 3.5 million year old skeleton (see icons at the right hand side of the home page:

http://www.nrf.ac.za/sajs/index.stm

so it would pay to keep watching to see what appears on the website when they update it to the new "current issue".

It would seem that they have managed to extract some of the skeleton ("pelvis, upper leg, ribs and backbone" according to BBC), enough so that they can say that this 3.5 My-old  Australopithecus (presumed) was bipedal and did not knuckle-walk like a chimp (Duh!!!).

Apparently the main argument Clark will put forth will be that the ape/human last common ancestor was also not a knuckle-walker, based on this 3.5 million-year-old skeleton's limb proportions and hand/foot morphology (having a "powerful thumb and a vice-like grip"). The issue of whether the ape/human LCA was a knuckle-walker or not has been argued since forever, and if evidence of a powerful gripping thumb in a skeleton approximately 3 million years evolved from the LCA is the argument's strong point,  I doubt whatever Clark (or Robin Crampton) has to say will put the issue to rest as decided.

Still, it's nice to hear that they've made some progress removing the skeleton from the matrix, and whatever the paper has to say, I'm sure it will be both interesting and informative.

Dar

Nothing very substantive, here.

Thanks for taking the time to come up with your views on this media item which, according to a recent note from Mikey Brass (I just read on another list), may well well be a rehashed story. This would not surprise me a bit, since this kind of curious journalistic behaviour appears to happen more and more frequently. In this regard, I suggest that from now on, we systematically qualify or identify (and criticize) these particular media bits as defrosted or warmed up news (some sort of a microwave food for thought). This said, one has to admit that they, nonetheless, generate an amazing amount of activity (and use of bandwidth -- this on other lists) on the part of hardcore palaeoanthropology, WEB aficionados, whose uncritical (at the very best) excitement threshold will never cease to fascinate me.

Jacques Cinq-Mars

[lagarvelho]

Jacques:

<Thanks for taking the time to come up with your views on this media item which, according to a recent note from Mikey Brass (I just read on another list), may well well be a rehashed story. This would not surprise me a bit, since this kind of curious journalistic behaviour appears to happen more and more frequently. In this regard, I suggest that from now on, we systematically qualify or identify (and criticize) these particular media bits as defrosted or warmed up news (some sort of a microwave food for thought). This said, one has to admit that they, nonetheless, generate an amazing amount of activity (and use of bandwidth -- this on other lists) on the part of hardcore palaeoanthropology, WEB aficionados, whose uncritical (at the very best) excitement threshold will never cease to fascinate me.>

You will have noticed, I hope, that I carefully said on "that other list", that the story *might* be kind of old. . . it sounded familiar to me, but I sent it on the grounds that I'd rather be safe than sorry.  And anyway, it was kind of quiet at the time.  Still, even discussion of "old" topics sometimes leads to fruitful insights.  
Anne G

[Jacques Cinq-Mars]

Jacques:

<Thanks for taking the time to come up with your views on this media item which, according to a recent note from Mikey Brass (I just read on another list), may well well be a rehashed story. This would not surprise me a bit, since this kind of curious journalistic behaviour appears to happen more and more frequently. In this regard, I suggest that from now on, we systematically qualify or identify (and criticize) these particular media bits as defrosted or warmed up news (some sort of a microwave food for thought). This said, one has to admit that they, nonetheless, generate an amazing amount of activity (and use of bandwidth -- this on other lists) on the part of hardcore palaeoanthropology, WEB aficionados, whose uncritical (at the very best) excitement threshold will never cease to fascinate me.>

You will have noticed, I hope, that I carefully said on "that other list", that the story *might* be kind of old. . . it sounded familiar to me, but I sent it on the grounds that I'd rather be safe than sorry.  And anyway, it was kind of quiet at the time.  Still, even discussion of "old" topics sometimes leads to fruitful insights.  
Anne G

And since the PALANTH - Forum is relatively quiet, I will have you notice that I have carefully used the plural ("lists"). I can assure you that there was nothing "personal", in my comments on the "excitement threshold" of a few people.

Jacques Cinq-Mars

[lizsom]

"Old" news in the sense that the find has been known about for a while, but the detailed description is still interesting. If the opinions given at the time of the original find prove correct, be even more interesting when the work has been completed on the diagnostic parts of the cranium. I can vaguely recall some talk about this possibly being a new species ..

Unless I am mistaken, this is the skeleton related to "little foot", where the hallux is somewhat divergent - combine that with a strongly grasping hand and we are clearly in the realm of facultative bipeds.

If memory serves, _A.africanus_ did not show any knuckle-walking traits in the wrist-bones in the Richmond & Strait paper, and I would rather like to see that finding corroborated for this specimen, which may be the case in the full publication.

(Richmond, B.G. & Strait, D.S. (2000) Evidence that humans evolved from a knuckle-walking ancestor. Nature 404 382-385 )

Liz Somerville
Sussex
UK

[lagarvelho]

Jacques:

"And since the PALANTH - Forum is relatively quiet, I will have you notice that I have carefully used the plural ("lists"). I can assure you that there was nothing "personal", in my comments on the "excitement threshold" of a few people."


Rest assured, I understood perfectly well that there was nothing "personal" intended.  I was just filtering it through what has been going on at "my end".
Anne G

[Greg Laden]

The interesting part of all of this is I think being missed by the reports:  There are one, in fact two (this news will come out later) australopith skeletons at the Transvaal Caves.  There was a time when australopith skeletons were represented mainly by Lucy, but now there are two individuals in South Africa with both skull materials and substantial postcranial material related to such features as locomotion.  The particular analyses notwithstanding, it is useful to make the point of association between particular skull adaptations (mainly related to diet) and particular postcranial adaptations (related to positional behavior, locomotion, body size, etc.) where you have parts of both from one individual.

[Daryl Habel]

Interesting news on this.

The Nov/Dec 2002 issue of the South African Journal of Science, containing the Clarke paper with new information on the StW 573 skeleton has appeared on the SAJS website, and from the website the abstract is cut-and-pasted below.  The "discovery" paper from 1998 is available in pdf (click appropriately in "Special Features" at right-hand side of webpage) at:  

http://www.nrf.ac.za/sajs/abnov02a.stm
************************************************
South African Journal of Science
Volume 98 No. 11/12 November/December 2002

Newly revealed information on the Sterkfontein Member 2 Australopithecus skeleton

R.J. Clarke*
*Sterkfontein Research Unit, School of Anatomical Sciences, University of the Witwatersrand Medical School, 7 York Rd, Parktown 2193, Johannesburg, South Africa.
E-mail: 107kath@cosmos.wits.ac.za

The continuing excavation of the Australopithecus skeleton from Sterkfontein Member 2 has uncovered the crushed pelvis together with the right upper femur, lumbar vertebrae and ribs. We now know that the breccia containing these remains had, soon after deposition, collapsed into a water-cut cavity beneath, which distorted the arrangement of the skeleton. The length ratios of the complete left arm to complete right leg appear to be subequal (although the bones are broken); these dimensions, together with the long thumb and relatively short fingers of the left hand, indicate that this individual was not a knuckle-walker nor did it derive from one. This conclusion argues against the commonly held view that humans are most closely related to chimpanzees and that both have a relatively recent common ancestor; such an ancestor would have been long-armed and knuckle-walked on the ground, in a way that is also similar to the locomotor behaviour of the gorilla. If in fact humans and chimpanzees share this ancestor, then early hominids would also have had the same knuckle-walking anatomy and it would have been a feature of Australopithecus. Instead, the Sterkfontein skeleton argues against recent shared ancestry, and reveals Australopithecus as bipedal on the ground and a branch-climber with subequal limb-lengths and long, powerful, opposable thumbs.
************************************************

[Martin Davison]

Not sure whether the following article has been mentioned in this forum but those interesed in this thread, and who may be startled by Clarke's rather radical conclusions, might like to compare his preliminary analysis of the Sterkfontein Australopithecus (africanus?) hand with the detailed work done by David Alba et al on a reconstructed A. afarensis hand from Hadar. See their article in the Journal of Human Evolution 44 (2003) 225-254, the abstract of which I append.

As for Clarke's inferences about the characteristics of the LCA and his tentative distancing of humans from chimps, I found some useful and reassuring analysis of these issues in Wolpoff's Paleoanthropology at p219.

Any comments on any of these issues from the forum experts?  

Abstract of Alba et al

The hands of apes and humans differ considerably with regard to proportions between several bones. Of critical significance is the long thumb relative to other fingers, which is the basis for human-like pad-to-pad precision grip capability, and has been considered by some as evidence of tool-making. The nature and timing of the evolutionary transition from ape-like to human-like manual proportions, however, have remained unclear as a result of the lack of appropriate fossil material. In this article, the manual proportions of Australopithecus afarensis from locality AL 333/333w (Hadar, Ethiopia) are investigated by means of bivariate and multivariate morphometric analyses, in order to test the hypothesis that human-like proportions, including an enhanced thumb/hand relationship, originally evolved as an adaptation to stone tool-making. Although some evidence for human-like manual proportions had been previously proposed for this taxon, conclusive evidence was lacking. Our results indicate that A. afarensis possessed overall manual proportions, including an increased thumb/hand relationship that, contrary to previous reports, is fully human and would have permitted pad-to-pad human-like precision grip capability. We show that these human-like proportions in A. afarensis mainly result from hand shortening, as in modern humans, and that these conclusions are robust enough as to be non-dependent on whether the bones belong to a single individual or not. Since A. afarensis predates the appearance of stone tools in the archeological record, the above-mentioned conclusions permit a confident refutation of the null hypothesis that human-like manual proportions are an adaptation to stone tool-making, and thus alternative explanations must be therefore sought. One hypothesis would consider manipulative behaviors (including tool-use and/or non-lithic tool-making) in early hominines exceeding those reported among extant non-human primates. Alternatively, on the basis of the many adaptations to committed bipedalism in A. afarensis, we propose the hypothesis that once arboreal behaviors became adaptively insignificant and forelimb-dominated locomotor selection pressures were relaxed with the adoption of terrestrial bipedalism, human-like manual proportions could have merely evolved as a result of the complex manipulation selection pressures already present in extant non-human primates.Both hypotheses are not mutually exclusive, and even other factors such as pleiotropy cannot be currently discarded.