miércoles, marzo 12, 2008

The "Palau man" paper: The return of precladistic paleontology?

I have just posted this message on the blog of the online community manager of PLOS:

Hi Coturnix,
I haven' heard yet much criticism of the Berger et al. paper, so I guess I'll be one of the first.

I consider that Berger hasn't really established that these tiny Palauans are H. sapiens. This could be a species close to H. sapiens (perhaps the closest known so far and thus "sister" species) that has retained some plesiomorphic traits yet shares several apomorphies with H. sapiens (until now thought to be "autapomorphies", exclusively of sapiens)

To discard this possibility and prove that tiny Palauans are H. sapiens, Berger et al. would have to show that their tiny Palauans are phylogenetically nested within H. sapiens (and not "right outside"). However they did not make a phylogenetic analysis (despite disposing of several specimens and good morphological data)

Without that, they are simply preferring hypotheses of convergence or reversal rather than homology for the primitive traits, which is contra-parsimony unless further evidence is provided; and for that, they would need phylogenetic analysis.
A little PAUP on the morphological traits, that's all I'm asking for. This is standard procedure in systematics and paleontology when describing a new fossil of evolutionary relevance. Statements such as "We feel that the most parsimonious, and most reasonable, interpretation of the human fossil assemblage from Palau is that they derive from a small-bodied population of H. sapiens" do not substitute for actual phylogenetic analysis using parsimony.
If Berger et al did that analysis, they would KNOW, rather than FEEL, whether "tiny palauans are H. sapiens" is REALLY the most parsimonious hypothesis or not.

1 comentario:

RSUAREZ dijo...

'ta el hueon chistosito del blog ese... no prendió con nada más que con el Ewok!! jajaja