The Pebanista yacuruna is a large (3 meters) species of freshwater dolphin believed to have inhabited the proto-Amazon region approximately 16 million years ago during the Miocene epoch. This ancient species was part of a freshwater ecosystem that developed in what is now Peru.
During that time, proto-Amazonia underwent significant environmental transformations, both geographically and ecologically. Tectonic plate shifts, changes in river flows, and the transition from large lake systems to modern river networks all contributed to the habitat dynamics of this species.
Initially, they thrived in more enclosed water environments such as large lakes and marshes rich in vegetation. However, climate changes and geological shifts gradually transformed proto-Amazonia into a more dynamic and expansive river system. This undoubtedly influenced the species' adaptation in terms of feeding patterns and migratory behavior.