Pachydon hettneri (Anderson, 1928) as indicator for Caribbean–Amazonian lowland connections during the Early–Middle Miocene

This article reports on new records of the bivalve Pachydon hettneri (Anderson, 1928) from Miocene deposits in Venezuela, Colombia, and Peru. In particular, we focus on findings in the Chaguaramas Formation of northern Venezuela. The stratigraphic resolution of these records was recently improved, narrowing the age of these deposits to late Early–early Middle Miocene (Burdigalian–Langhian). These new Pachydon records imply that during the Burdigalian–Langhian, a lowland aquatic biogeographic connection existed between the Amazon region and Venezuela through the East Andean foreland basins. The species Pachydon hettneri may have given rise to evolutionary radiations in the Middle Miocene Pebas ‘long-lived’ lake-wetland system in Amazonia.