Complimentary Phylogenetic Signals for Morphological Characters and Quantitative 3D Shape Data within genus Homo

TL;DR

This study demonstrates that morphological characters and 3D shape data provide complementary phylogenetic signals for Homo, and combining them yields more consistent evolutionary trees than using either alone.

Contribution

It shows that integrating morphological and 3D shape data improves phylogenetic inference for Homo, challenging the notion of conflicting signals from different data types.

Findings

Combined data sets produce more consistent phylogenetic trees.

Different analysis methods can converge on similar evolutionary relationships.

Diverse approaches enhance understanding of Homo phylogeny.

Abstract

Estimating the phylogeny of the genus Homo is entering a new phase of vastly improved data and methodology. There is increasing evidence of 6 to 10 competing species/lineages at any point in the last half million years, making the elucidation of the relationships of individual specimens particularly important. Recent estimates of the phylogeny of key specimens include Waddell (2013, 2014, 2015, 2016), and Mounier et al. (2016). These are made with quite different data (3D skull shapes and discrete morphological characters, respectively) and methods of analysis (unweighted least squares fitting of distances, OLS+, and reweighted maximum parsimony, respectively). Initial inspection of the trees in these articles might leave the impression of a great deal of disagreement and confused results. Here it is shown this need not be the case, and that these two types of data and analysis may be indicating a very similar tree, one that is in good agreement also with subjective current wisdom/expert opinions on particular parts of the phylogeny. The precise location of the African LH18 specimen arises as key to a better understanding of the likely form of the last common ancestors of H. sapiens and Neanderthals. A diverse approach seems to bring forth much more agreement of trees than otherwise perceived, and argues against being dogmatic about methods of phylogenetic analysis particularly when working with difficult problems.