Phylogenetic Signal in Bone Histology

Abstract

The potential presence of a phylogenetic signal in the variation of bone histological and microstructural features, and its potential utility in phylogenetic reconstruction and in taxonomic determinations of bone fragments, have been discussed for over a century and a half. Some authors have argued that variation in bone histological and microstructural traits is essentially the outcome of ontogenetic and functional factors, others have hypothesized that it contains a significant phylogenetic signal and diagnostic taxonomic information. For pure functionalists, characteristics inherited from a common ancestor appear as constraints that prevent organisms from reaching an optimal adaptation to the function. In contrast, for phylogeneticists, functional adaptations of species to local conditions (autapomorphies) blur the phylogenetic signal. Here we show with empirical data that these points of view are not mutually exclusive. Quantifications performed on a broad phylogenetic scale using sparse sampling, and on a narrow phylogenetic scale using an exhaustive sampling, lead to similar conclusions: phylogenetic signal in osteohistological traits is moderate to low.