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

肯尼亚北部和埃塞俄比亚的图尔卡纳盆地是世界上最重要的古人类化石所在地之一，特别是在2.3-1.5 Ma的关键时期，当时气候和环境变化被认为是人属起源的驱动力，并负责在1.9 Ma左右将其迁出非洲。与人类化石不同的是，在图尔卡纳盆地上新世和更新世的许多贝壳层中，软体动物非常丰富。该项目的目标是评估这些软体动物的进化和古生态，同时考虑到气候和环境变化与古人类进化之间的可能关系。图尔卡纳软体动物在语境中被断断续续的平衡理论辩论。由于我们已经提出了解释图尔卡纳盆地软体动物进化模式的替代假说，我们在这里建议更严格地检验这些假说。因此，软体动物的多样性和随时间的差异反映了水生系统的环境变化(Anagenesis)，而不是分支形成(例如物种形成)。我们计划在实地收集的基础上，结合沉积学和挖掘学数据分析相关数据。我们还将应用精算生物学方法，利用今天马拉维湖类似环境中的分子遗传数据。最终目的是将这些数据与地质和地球化学数据结合起来，以重建图尔卡纳盆地的水文和软体动物的演化，以更好地了解东非在我们起源的关键时期的古人类生态。

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