Investigation of the hydrogeographical evolution of southwest China based on freshwater crab biogeography

• Applicant: Privatdozent Dr. Sebastian Klaus
• Subject Area: Evolution, Anthropology
• Term: from 2014 to 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 268250802

In fluviatile environments, allopatry between drainages can be considered as a major driver of diversification in aquatic organisms. While separation between drainages can be an active process via dispersal over land, in many cases the rearrangement of river systems isolated populations and caused subsequent speciation.This project deals with the historical biogeography of the diverse primary freshwater crabs of Southwest China (family Potamidae). These inhabit a highly dynamic landscape that experienced major geographical changes during the last ten million years due to drainage rearrangements in the course of the uplift of the Tibetan plateau. Dating of these drainage re-arrangements remains a difficult endeavour in geosciences, even though this information is crucial to understand landscape evolution and can help to estimate uplift rates. Given that these geographical changes are often associated with speciation, these events are likely to be reflected by phylogenetic patterns. I intend to extrapolate the timing of drainage rearrangements in Southwest China (Sichuan, Chongqing) based on a dated freshwater crab phylogeny.(1) I ask wether colonization of the Sichuan basin with potamid freshwater crabs occurred (a) via Yunnan from the south, and/or (b) via the lower Yangtze from the east. In the first case colonization most likely correlates with the final capture of the upper Yangtze, in the latter case freshwater crabs most likely spread upstream with the successive captures of the middle Yangtze tributaries, or reversal of the middle Yangtze, respectively.(2) Based on time-calibrated phylogeny of the freshwater crabs I try to answer if reversal of the middle Yangtze is an old, Miocene event that occurred during initial rise of the Tibetan plateau and adjacent areas, or if it is not older than Pliocene.This project will be embedded in a larger joint research project lead by the Chengdu Institute of Biology, Chinese Academy of Sciences, targeting evolution of aquatic organisms and drainage development in Southwest China.

• DFG Programme: Research Grants