Central Asian radiation of modern large-mammal faunas in Miocene.

Abstract

Elucidating how modern faunas were established is crucial for understanding mammalian evolution in response to the Cenozoic global climatic and tectonic changes. However, complicated exchanges of faunas between continents in the Late Cenozoic have made it challenging to identify general patterns of faunal evolution and migration. We developed a method, faunal phylogenetic contribution, to quantify faunal relationships based on taxon distances in a supertree. Our results suggest Central Asia faunas exhibited two notable expansion phases: 19 to 16 million years (Ma) ago (pre-Tunggurian surge) and 11 to 9 Ma ago (Bahean surge). The latter phase was directly correlated with formation of the modern large-mammalian faunas, driven by the ecomorphological revolution of local mammalian communities following a regional mass extinction, "the Central Asian Tortonian Crisis." We propose that the rapid uplift of the Tibetan Plateau altered Central Asian hydrological system, promoting aridification and earlier development of open habitats, which in turn drove the adaptation of large mammals to prolonged environmental shifts.