The microevolution of modern human cranial variation: implications for hominin and primate evolution

Abstract

Context: Reconstructing the evolutionary history of fossil human taxa is heavily reliant on the ability to extract phylogenetic information from patterns of morphological variability. However, attempts to reconstruct phylogenetic relationships from craniodental data in extant primates have yielded inconsistent and inconclusive results.

Objective: To critically evaluate a recent body of research, conducted within an explicitly quantitative genetics framework, which investigates the extent to which human cranial variation reflects past population history. Possible ways in which to extrapolate these human-specific insights to higher taxonomic levels will also be assessed.

Results: A consensus is emerging confirming a largely neutral model for the human cranium, although specific instances of climatic and dietary adaptation have also been uncovered. Also, specific regions of the cranium, delineated according to particular criteria, differ in their relative genetic congruence. However, the genetic congruence patterns identified in modern humans are not replicated in other extant primates, calling their generality into question.

Conclusions: Developing a clearer understanding of the evolution of morphological diversity in extinct taxa requires a different inference approach that focuses on assessing the evolutionary forces that shape these patterns, rather than the identification of particular morphological regions that correlate with genetic relatedness across all primates.

• Extant primate models
• fossil hominins
• macroevolution
• microevolution
• phylogenetics

Acknowledgements

I would like to thank Kevin Kuykendall and Sarah Elton for the invitation to present at the SSHB symposium “The Human Biology of the Past”. I am grateful to Stephen Lycett, Heather Smith and an anonymous reviewer for helpful comments on an earlier draft of this manuscript.