Dental Microwear of Miocene Primates from the Turkana Basin of Northern Kenya

Comprehending the dietary patterns of Turkana Basin primates from the late Paleogene and early Neogene can contextualize the role of food choice in the evolution of higher primates in Africa. Dental Microwear Texture Analysis (DMTA) quantifies wear on the enamel of a tooth and can be used as a proxy to infer aspects of a taxon’s diet in the past. DMTA can provide insight into what specific animals in the past ate, rather than what they were capable of eating, and by extension, reflect food availability related to habitat preferences or environmental fluctuation. Here, primates from six Oligocene through Pliocene sites around the Turkana Basin of northern Kenya were compared to extant primates and to one another to characterize microwear and contribute to our understanding of dietary preferences. Sites used here are Topernawi (Oligocene), Buluk (Miocene), Loperot (Miocene), Locherangan (Miocene), Lothagam (Miocene/Pliocene), and Napudet (Pliocene). Primates were grouped as follows on the basis of provisional taxonomic attribution: Victoriapithecid, Colobinae, Cercopithecinae, Hominoid, and “Primate”. It was expected that the dental microwear dietary signatures would differ between the primate groups and the between Miocene and non-Miocene localities due to the changes in environment occurring during the Miocene, where the Turkana Basin became drier and more seasonal from the Oligocene through the Pliocene. A white-light confocal profiler microscope was used to scan surfaces of replicas for DMTA. Standard microwear texture attributes were characterized for each specimen and MANOVA, ANOVA, and pairwise comparisons were used to determine significance of models comparing sites and primate groups. Topernawi and Napudet samples differed significantly from the other sites for both complexity (Asfc) and anisotropy (epLsar), indicating that primates from those sites were eating mechanically different foods than those from the Miocene localities. There was no variation present between the remaining sites. Surprisingly, primate groups did not differ when considering central tendencies, possibly due to small sample sizes. Despite this, comparisons of the primates and sites considering dispersion yielded marginal and significant variation in feature sizes (Smfc). The foods consumed at these sites also appear to have produced variable degrees of surface heterogeneity (Hasfc9) and feature sizes (Smfc). The sites were additionally variable for dispersion when considering Asfc. Topernawi and Locherangan differed from the other sites, indicating a broader values of surface complexity for Asfc. The Miocene primates studied here (both cercopithecoids and non-cercopithecoid catarrhines) fell closest to extant folivore-frugivores in their texture values, consistent with a preference for a mosaic of open woodlands and fluvial plains. Due to their small sample sizes, the overall dietary preferences of the primates from the Oligocene and Pliocene sites are currently unclear and require additional study. Despite the small sample sizes, the resulting microwear data contributes to a larger multi-proxy study of community paleoecology of Turkana Basin primates