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Creators/Authors contains: "Oginga, K"

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  1. Tectonically driven physiographic evolution in early Miocene of eastern Africa significantly shaped landscapes, climates, and vegetation, resulting in habitat heterogeneity. Early hominoids inhabited these landscapes, and their evolutionary history was likely influenced by these heterogenous environments. In western Kenya, around the extinct Tinderet Volcano (ca. 19-21Ma), fossil-rich exposures offer crucial insights into this history with evidence of early hominoids. Here we use analyses of sedimentology, paleosol paleoclimate proxies, fossil leaves, and forestry metrics, to reconstruct the paleoclimate and paleoecological reconstruction of the Koru-16 fossil site. Sedimentological and stratigraphic analyses at Koru-16 reveal a landscape marked disturbance created by periodic volcanic eruptions and stable intervals marked by moderately to poorly developed paleosols. Paleoclimate reconstructions based on paleosol geochemistry indicates warm and wet conditions. Over 1000 fossil leaves were collected from the Koru-16 site, representing 17 morphotypes across two stratigraphic intervals. Mean annual precipitation estimates based on leaf size of shape indicate >2000mm/yr. Leaf lifespan reconstructions reveal predominantly evergreen taxa with a distribution leaf lifespan, similar to modern equatorial African rainforests. Fossil tree stump casts suggest an open forest, similar to contemporary tropical forests supporting large-bodied primates. Importantly, fossil leaves, the tree stump casts, a medium-sized pythonid, and multiple specimens of large-bodied primates occur in the same stratigraphic layer demonstrating their cooccurrence in the Koru-16 ecosystem. The multi-proxy paleoclimate and paleoecological reconstructions for Koru-16 converge on a very wet and warm climate supporting a closed, tropical seasonal forest to rainforest biome. This environment likely provided an ideal habitat for early hominoids, emphasizing the role of forested habitats in their early Miocene evolution. Additional work is ongoing on refining the paleosol paleoclimate estimates with a more recent model and δ13C analysis of soil organic matter will help to further refine these reconstructions. 
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