Impact of methodological choices on assessments of the reliability of fossil primate phylogenetic hypotheses

It has been argued in several recent studies that conventional craniodental characters cannot be assumed to be reliable for the purposes of reconstructing primate phylogenetic relationships and that as a consequence little confidence can be invested in published fossil primate phylogenies. Here, we evaluate this claim by revisiting the analyses reported in one of these studies [Collard and Wood, 2000]. Specifically, we investigate whether the use of alternative methodological procedures would have altered their findings. We focus on three key issues: (1) size correction, (2) outgroup composition and (3) non-phylogenetic correlation among characters. Our analyses suggest that the results of Collard and Wood [2000] were not affected by the size correction method they used or by the outgroup they employed. Our analyses also suggest that their results were not affected by their decision to ignore developmental, functional and other non-phylogenetic correlations among the characters in their data sets. Accordingly, our study supports the assertion that conventional craniodental characters cannot be assumed to be reliable for reconstructing primate phylogenetic relationships. This in turn suggests that many published fossil primate phylogenies may be unreliable.