Sophie Edwards

The hominoids of the late Miocene and early Pliocene have been studied in relatively little detail in relation to the tumultuous climate change within which they inhabited. A more thorough account of how shifting paleo-environments affected the evolution of contemporary hominoids can be achieved by studying the shape variation of the craniomandibular morphology of relevant fossil specimens.

Landmark-based Geometric Morphometric analysis is a powerful tool that can assist in the quantitative analysis, interpretation and visualisation of the shape variation that exists between varying species of this era, which inhabited different climates. Within this study, varying hominoid crania and mandibles, both modern and extinct i.e. Sahelanthropus, Homo, Ardipithecus etc., will be imaged through a desktop 3D scanner. Landmarks will be placed on specific homologous anatomical points onto the resulting scanned images. These will be uploaded to Geometric Morphometric software, ie. the R Project, which will computationally quantify the shape variation of the craniomandibular aspects of the specimens.

This research will examine the earliest forms of hominoid morphology and how they relate to paleohabitats with the aim of elucidating the impact environment had on the selective pressures that shaped contemporary evolutionary trajectories. Further comparison with Great Ape morphological variation and ecological contexts should yield data as to how clades reacted and adapted to varying selective pressures that in turn reflect modern morphological variation. From this starting point it should be possible to explore the patterning of Great Ape and Hominin responses to environmental variation across difference biomes. Analysis and modelling should provide data to address the following questions:

• In which habitat did encephalisation seem to occur most rapidly?
• Did the Great Apes of these periods undergo similar adaptations in similar environments?
• Why, if found in similar biomes did early Great Apes and Hominins diverge along very different evolutionary pathways?

Ultimately this research will provide a better foundation for understanding the evolution of the hominid skull. Understanding the extent to which variation in cranial morphology occurs between species is a vital component for understanding how environmental factors contributed to manipulating our evolutionary pathways.