Miocene fish faunas from the northwestern Amazonia basin (Colombia, Peru, Brazil) with evidence of marine incursions

New evidence indicates marine influences during the Miocene in the northwestern Amazonia basin. This is the first major survey of the ichthyofauna from this area in the Miocene. Fossil fish remains from taxa such as the Dasyatoidea, Myliobatoidea, Characiformes, Siluriformes and Sciaenidae are found. Conspicuous finds were two pharyngeal teeth of Stephanodus minimus, a species that so far had only ever been found in Late Cretaceous sediments. The fish remains of freshwater, brackish and marine taxa are deposited together throughout the area. This is thought to be related to marine influences during the Miocene. These finds agree with earlier studies that suggest episodic marine influences, which most likely lasted up to the Late Miocene, and disagree with studies that suggest a connection between the Atlantic and the Caribbean Sea over the South American continent. The ichthyofaunas also indicate a warm climate, as well as shallow and possibly torrential waters.