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Sunday, September 13, 2015

Scientists Prove Hobbit/Dmanisi Detractors Wrong for the Hundredth Time

Bayesian analysis of a morphological supermatrix sheds light on 
controversial fossil hominin relationships. 

Mana Dembo, Nicholas J. Matzke, Arne O. Mooers, Mark Collard. 


The phylogenetic relationships of several hominin species remain 
controversial. Two methodological issues contribute to the 
uncertainty—use of partial, inconsistent datasets and reliance on 
phylogenetic methods that are ill-suited to testing competing 
hypotheses. Here, we report a study designed to overcome these issues. 
We first compiled a supermatrix of craniodental characters for all 
widely accepted hominin species. We then took advantage of recently 
developed Bayesian methods for building trees of serially sampled tips 
to test among hypotheses that have been put forward in three of the 
most important current debates in hominin phylogenetics—the 
relationship between Australopithecus sediba and Homo, the taxonomic 
status of the Dmanisi hominins, and the place of the so-called hobbit 
fossils from Flores, Indonesia, in the hominin tree. Based on our 
results, several published hypotheses can be statistically rejected. 
For example, the data do not support the claim that Dmanisi hominins 
and all other early Homo specimens represent a single species, nor 
that the hobbit fossils are the remains of small-bodied modern humans, 
one of whom had Down syndrome. More broadly, our study provides a new 
baseline dataset for future work on hominin phylogeny and illustrates 
the promise of Bayesian approaches for understanding hominin 
phylogenetic relationships. 

Also, Australopithecus sediba "groups with Homo and may be its 
ancestor" (but implying a stratigraphic gap of 300.000-800.000 years), 
and Sahelanthropus is the most basal hominin, followed by Ardipithecus 
(Orrorin was not included in this study). 


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