Congruence of Cranial and Genetic Estimates of Old World Primate Phylogeny

Abstract

Abstract Inferring the phylogenetic relationships amongst fossil hominins is necessarily based on morphological data. Attempts to reconstruct fossil hominin phylogeny have yielded inconsistent and inconclusive results. Old world primates – apes and old world monkeys – provide key referents for understanding the phylogenetic signal in cranial data. Application of phylogenetic methods to cranial data from primate taxa has failed to uncover the known molecular genetic relationships of these major primate groups, suggesting that hominin phylogeny based on morphological data cannot be estimated with complete accuracy. Propositions regarding the potential efficacy of individual cranial regions have been empirically tested in both apes and old world monkeys. No clear criteria have been uncovered to predict the potential efficacy of cranial regions. However, recent studies have suggested that the taxonomic scale of the analysis and the allometric scaling relationships amongst taxa may both play key roles in determining the phylogenetic efficacy of cranial data. Key Concepts: Palaeoanthropologists rely on fossilised cranial remains to infer evolutionary history of hominins. Extant primates form necessary inference models for understanding human evolution. Attempts to reconstruct hominin phylogenies have generated inconsistent results. Some cranial traits are likely to be more reliable for reconstructing phylogeny than others. Masticatory traits have higher within‐taxon variance than nonmasticatory traits, but do not have lower phylogenetic efficacy. Basicranial traits may have higher phylogenetic efficacy in some primate groups. No clear rules exist for deciding which cranial traits have the greatest potential to uncover hominin relationships. Allometric scaling relationships among taxa affect the inference of phylogenetic relatedness. Taxonomic scale at which cranial–genetic congruence analyses are conducted may also be important.