November 25, 2009 | David F. Coppedge

Ardi Party Is Over

The hubbub over Ardipithecus (10/02/2009) may have been premature.  Despite 600 pages of material submitted to Science in October, many doubts and questions remain about the status of this hominin, or hominid, or whatever it was (the nomenclature is confusing and inconsistent even among paleoanthropologists).  In an article by Katherine Harmon in the pro-evolutionary magazine Scientific American, so many doubts are evident that laymen should seriously question whether this fossil suggests anything about human origins.   In brief, here are some key issues:

  1. Debate:  Ardi has “sharpened more differences than it has smoothed over.
  2. Manipulation:  William Jungers (Stony Brook U) criticized Tim White’s team for overstating interpretations.  “I think some of the things they said might have been for effect,” he claimed.
  3. Negative evidence:  Even White himself does not claim that Ardi demonstrates linkage to humans.  Harmon wrote, “White and his fellow authors do not propose to have a definitive answer, but through painstaking analysis of the fossil data and surroundings, they conclude in the overview paper that, ‘There are no apparent features sufficiently unique to warrant the exclusion of Ar. ramidus as being ancestral to Australopithecus,’ thus proposing she might indeed be an early hominin (the ever-changing nomenclatural group that usually includes living humans and our close extinct relatives, also referred to by White et al. as hominids—although the latter title now often includes the great apes, as well).”
  4. Rotation:  Key to the claim that Ardi walked upright is the position of the ilium.  Rotating the ilium can lead to mistaken interpretations.  Jungers said, “It’s very difficult not to make them look like something you have in your mind if there’s any chance of play.” Harmon mentioned that “Despite the numerous images and descriptions put forth by the researchers, others are reluctant to take the reconstructions without a grain of salt.
  5. Faculty:  Humans are obligate bipeds, but facultative tree climbers.  If Ardi was a facultative biped and obligate tree climber, as her divergent big toe indicates, she may have been no different in her transport habits than chimpanzees.  No knee joint was found in the Ardipithecus specimens.  This also confuses the interpretation.
  6. Social studies:  White and the supporters of Ardi argue that the teeth show little sexual dimorphism.  What does this mean?  They take it to mean that males were not larger and more aggressive, which means that they might have helped care for the young, which seems kind of human-like.  This reasoning is very subjective.
  7. Face book:  So what if Ardi’s face was not as protruding as that of apes?  Harmon explained, “outside researchers focus on the similarity in size to other nonhuman primates, such as extinct Miocene epoch apes.
  8. Combination plate:  Tim White prefers to look at the combination of features that make Ardi unique, instead of focusing on piecemeal analysis of each part.  This raises questions, however, about the value of his own painstaking descriptions of those parts.  David Begun (U of Toronto) also opined that it could mean Ar. ramidus had nothing to do with human evolutionary history.  In Ardi he finds “very little in the anatomy of this specimen that leads directly to Australopithecus, then to Homo sapiensThis could very easily be a side branch.

About the only thing they agree on is the amount of detail White’s team put into the description of the fossil is commendable.  Jungers considers the work a “new standard” that is “truly extraordinary.”  That aspect, however, affirms nothing about the interpretation of its place in human evolution.  It might only serve to elucidate the sophistication of their subjectivity.

*Sigh.*  The Darwin Party song and dance is getting so tiring.  Lots of old apes and monkeys went extinct.  Who cares about another?  Considering the rivalries and ambitions among the paleoanthropologists, and the ever-changing stories, and the leeway for fudging that exists, why do we even pay these guys any attention?  Here at CEH we have to, in order to forestall the misguidance of the public that results from one-party rule in Science.
    In support of that criticism, let us remind you of Tim White’s own cautions about how distorted bones can mislead even the experts (see 03/28/2003).  Let us remind you that Nature accused Tim White’s storytelling proclivities as “more philosophy than fossils” (04/27/2006).  Let us remind you that variability within humans can swamp interpretations of putative ancestral traits (07/22/2007).  And to reinforce the subjectivity of their art, let us remind you of Leslie Hlusko’s debunking of three common presumptions anthropologists use when interpreting alleged hominid bones (02/19/2004).  If you follow this stuff, consider it sport or entertainment – not science.

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