A Multi Proxy Analysis of Australopithecus anamensis Paleoecology in the Omo-Turkana Basin Open Access
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Australopithecus anamensis, possibly the earliest fully bipedal hominin, lived in eastern Africa c.4 million years ago (Ma). Three fossil localities in the Omo Turkana Basin (Kanapoi, Allia Bay and Mursi) preserve sediments from c.4 Ma. However, the fossil evidence for A. anamensis within the Omo Turkana Basin is not equally distributed across the three sites. The majority of the fossils within the Omo Turkana Basin attributed to A. anamensis come from Kanapoi (c.70%), c.30% come from Allia Bay, and none come from Mursi. Preliminary paleoecological analyses suggest that there were differences in the environments of these three sites. This dissertation project tests hypotheses relating hominin abundance to habitat and answer the following overarching question: What were the paleoenvironments of Australopithecus anamensis in the Omo Turkana Basin and how did they vary among the three known penecontemporaneous fossil localities? This project uses a multiproxy approach and combines taxonomic, stable isotopic, ecomorphological, mesowear and taphonomic data taken from faunal fossils assemblages from each locality to reconstruct the paleoenvironments. Chapter 1 introduces the localities and the research objectives. Chapter 2 is an analysis of ungulate mesowear focused on the site of Kanapoi. Chapter 3 is a multi proxy paleoecological analysis of Bovidae from Allia Bay. Chapter 4 provides insights into humidity in the Omo Turkana Basin around 4 Ma by studying taphonomy and the paleoecology of suids. Chapter 5 presents the overarching conclusions of the dissertation. This dissertation allows for a better understanding of the paleoenvironmental context of the earliest obligate biped. Analyses presented here reveal that A. anamensis was more common in relatively open and dry habitats and absent in humid and more closed settings. These conclusions are in line with A. anamensis behavioral and morphological reconstructions, including C3 hard-object feeding as well as traits characterizing the hominin lineage including an elongated body plan, the loss of hair, the ability to sweat, and obligate bipedal locomotion.