Miocene long-lived lake Pebas as a stage of mollusc radiations, with implications for landscape evolution in western Amazonia

摘要: The Miocene Pebas system was a huge (> 1 million km2) of long-lived lakes and wetlands that occupied most western Amazonia between c. 23 8 Ma. Remarkable endemic radiations molluscs ostracods occurred in the system. continuity many lineages 17 9 Ma shows never fully replaced by fluvial or marine settings. Many invertebrate groups developed an unusual range morphologies reflect adaptation to specific ecological stresses provided system, such as chemical stress, common dysoxia high predation pressure. Mollusc diversity increased especially during Middle Miocene. pathways for mobile organisms transfer into freshwater biotopes, at same time obstructed exchange terrestrial biota tropical Andes Guyana region. Short-lived, lowland aquatic corridors over northern shield regions through Ecuadorian Andean region almost certainly existed. terminated just before establishment modern Amazon (slightly Ma), possibly coinciding with single, wide ranging incursion Amazonia. With termination mollusc fauna became largely extinct. large tracts land development Subsequent diversification has been enhanced edaphic heterogeneity Formation deposits.