A Plethora of Journal Articles

Like most science bloggers I accumulate a wide variety of articles, some of which I not read until quite awhile after I find them. So, I thought one way of working through them would be to blog about them on a weekly basis, say on a Sunday. I’m thinking a short post about one or more articles with links (whenever possible) to the article(s) in question.

Locomotion and body proportions of the Saint-Cesaire 1 Chatelperronian Neandertal
This is by Trinkaus, Ruff, Churchill, and Vandermeersch. They perform a cross sectional analysis of the right femur of Saint-Cesaire 1 and conclude that although Saint-Cesaire 1 displays the same cold adapted morphology as other European Neanderthals, it displayed morphology indicating mobility behavior similar to early modern humans. As they put it:

At the same time, there is evidence of a shift in locomotor patterns, with the presence of the femoral anteroposterior reinforcement associated with increased mobility and seen more frequently among early modern humans than among the Neandertals. The impression is of a late Neandertal, in the context of significant cultural change, reflecting in its otherwise fully Neandertal biology the emergence of an early modern human behavioral pattern.

Arboreal and Terrestrial Traits as Revealed by the Primate Ankle Joint
This paper looks at the morphology of the ankle of a wide variety of primates (including one hominin) and tries to distinguish between arboreal and terrestrial locomotion. The paper comes to some interesting, and somewhat counterintuitive, conclusions:

A functional analysis of the newly discovered ankle joint of the Late Pliocene Old World monkey Paradolichopithecus arvernensis leads to the conclusion that this monkey not only had a terrestrial way of life, but has also a gait similar to that of Australopithecus afarensis,
revealing thus a parallel evolution between cercopithecoids and hominoids in this respect. The evolution of the australopithecine-like locomotion in Paradolichopithecus leads to the conclusion that the hominine pattern is not unique. The evolution of highly terrestrial locomotion in the Old World monkey Paradolichopithecus was, just as it was in Australopithecus, essential to enter an open plain to cover large distances in search for food. Paradolichopithecus shares its type of locomotion with Australopithecus, who is considered to have displayed a substantial degree of bipedalism in its locomotory repertoire.

Personally, I’m a bit skeptical of this conclusion.

7 Responses

  1. I can’t say anything about the australopithecine paper, but I’ve read the Trinkaus and Ruff paper(though quite a while ago), and I found it interesting, but I’m not really sure what to make of the conclusion.
    Anne G

  2. If, as some have argued, the Chatelperronian represents a Neanderthal change in behavior in the face of Homo sapiens and their Aurignacian technology one would also expect to see changes in Neanderthal behavior – including mobility patterns. Trinkaus et al are arguing that this is exactly what we see in the otherwise cold adapted St. Cesaire femur. The changes in cross sectional indices are not genetic, rather they are the result of skeletal plasticity. If Homo sapiens or Neanderthals are subjecting their femurs to the same biomechanical loadings the response should be roughly similar in terms of buttressing and so forth.

  3. Care to explain your skepticism for the latter?

  4. Well, the femur, tibia, humerus, etc, are similar to any other primate terrestrial quadruped, which makes me somewhat skeptical of the conclusion.

  5. After reading the second paper, I too remain skeptical of the conclusion that this ancient monkey would have been bipedal after the fashion of Australopithecus afarensis. I can’t see that the need to cover a lot of open territory in search of food impels bipedalism. Baboons and chimps cover open territory on four limbs. So do wolves, horses, deer, lions, etc. Maybe I’m just dense but I just don’t see why needing to cross open country would make a 4-limbed critter get up on its hind limbs and walk on 2 feet. It seems counterproductive.

  6. I also think the differences in the talus between baboons and Paradolichopithecus are overstated, as are the similarities between Paradolichopithecus and Australopithecus afarensis.

  7. According to Ian Tattersall and Jeffrey Schwartz (Extinct Humans, 2001), Australopithecus afarensis was not 100% terrestrial, anyway. They cite evidence from greater angling of the femur at the knee joint, the short legs and long arms, the curved shafts of the long bones of both limbs, and a groove along the back of the lower end of the fibula which is deeper than that found in humans or chimps, allowing afarensis to stabilize its foot when pressed against a vertical surface (pp. 89-91). All these things make them think that this hominid (sorry, my blog host, to talk about you to your face this way) was “more committed to life in the trees than on the ground.” That might be a bit overstated, but it does seem to take a bit off the certainty of the conclusions about Paradolichopithecus being both terrestrial and bipedal.

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