Palaeoecology and evolution of Pliocene-Pleistocene Turkana Basin molluscs: Implications for basin formation and the evolution of hominins in East Africa

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The Turkana Basin in Northern Kenya and Ethiopia is among the most important places for hominin fossils in the world, particularly from the crucial period between 2.3 and 1.5 Ma, when climatic and environmental changes are supposed to be the driving force in the origin of the genus Homo and responsible for its migration out of Africa around 1.9 Ma. In contrast to hominin fossils, molluscs are very abundant in many shellbeds from the Pliocene and Pleistocene of the Turkana Basin. The goal of the project is to evaluate the evolution and palaeoecology of these molluscs, also in view of the possible relation between climatic and environmental changes and the evolution of hominins. The Turkana molluscs were debated in context with the theory of punctuated equilibrium. As we have suggested alternative hypotheses explaining the pattern of mollusc evolution in the Turkana Basin we here propose to test these hypotheses more rigorously. Accordingly, diversity and disparity of molluscs through time reflect environmental changes in the aquatic system (anagenesis) instead of cladogenesis (e.g. speciation). We plan to analyse relevant data in concert with sedimentological and taphonomical data based on field collections. We will also apply an actuopalaeontological approach utilizing molecular genetic data from a similar setting in Lake Malawi today. The eventual aim is to combine these data in an international collaboration with geological and geochemical data in order to reconstruct the hydrology of the Turkana Basin and the evolution of molluscs to gain a better understanding of the palaeoecology of hominins in Eastern Africa at a critical time in our origin