Homo floresiensisn’t?

23 August 2006

Carl Sagan (paraphrasing LaPlace) famously observed that in science, “extraordinary claims require extraordinary evidence.” The 2004 announcement of a new species of “dwarf” hominid, based on subfossil material from the Indonesian island of Flores was in all respects extraordinary. Dubbed Homo floresiensis, our new cousins were quickly and cutely rebranded as “hobbits” by the popular press.

 


Two page spread from the April 2005 issue National Geographic (German language version).

The evidence, for its part was similarly extraordinary, a remarkably complete set of remains including a softball sized skull which appeared to be more closely akin to H. erectus than to H. sapiens. Associated with the skeleton were numerous lithics, the remains of tools used to hunt and process food. This material, along with additional skeletal remains were taken as the legacy of an extinct race of miniature humans with a unique evolutionary history.

 


Varying degrees of smugness in H. erectus (left) “H. floresiensis” (center) and H. sapiens (right and rear). (AP)

Of course one investigator’s exceptional proof is another’s dubious outlier. Much like the similarly extraordinary reports of extant Ivory-Billed Woodpeckers in the woods of Arkansas, the description of H. floresiensis garnered immediate rebuttal. The new skeleton was not a new species, said the critics, but a pathologic H. sapiens fossil, one with some type of microencephaly.


Reconstruction of H. floresiensis by Peter Schouten (left) and photograph of a microcephalic H. sapiens (right). This figure is an out of place artifact.

Partisan camps formed quickly and a publishing war began with both groups repeatedly declaring victory but failing to close the debate. The latest definitive report comes from an international team of Indonesian, Chinese, American and Australian scientists. Writing in this weeks PNAS, the authors conclude from a 140 point analysis of the skull that it is the remains of a diseased human (H. sapiens) with an abnormally small skull from a naturally small-statured (i.e pygmy) population.

 


The extreme asymmetry of the Flores skull is taken by Jacob et al. (2006) as an indication of pathology.

While I’m sadly under-qualified to have a relevant opinion on the validity of the taxon, I am reasonably certain that the debate is far from closed.

Of course, extraordinary debate is nothing new to paleoanthropology. The original H. erectus fossils, found by Eugène Dubois on the Indonesian island of Java in 1891, remained bones of contention until Dubois’ death in 1940. Dubois’ accession of the remains into a box hidden underneath his dining room floor and stubborn refusal to allow other scientists to examine the fossils didn’t help matters.

Last year’s report that the Indonesian government is denying access to the cave where the H. floresiensis remains were found is troubling. Even extraordinary evidence is useless when it’s kept out of reach of the global scientific community.

Extensive discussion of the H. floresiensis controversy, as well as a detailed analysis of the most recent rebuttal can be found at John Hawks’ weblog.

Above and below: New species or diseased pygmy?

One Response to “Homo floresiensisn’t?”

  1. Carel Says:

    Last year’s report that the Indonesian government is denying access to the cave where the H. floresiensis remains were found is troubling.

    It’s reminiscent of the Marcos government’s closing access to the “Tasaday” in the ’70s. Nice to see you back in the blogosphere.


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