Isthminia

Isthminia is an extinct genus of medium-sized river dolphin that lived during the Late Miocene epoch, about 6.1 million to 5.8 million years ago, along what are now the coasts of Panama. Its name honors the Republic of Panama and its people. The type species, Isthminia panamensis, is known from fossils found in the littoral Chagres Formation, including a partial skull. From that material the animal is estimated to have been about 2.85 metres long, and its habits suggest that it lived a predominantly marine life, which makes it a notable relative of the river dolphins now confined to South American rivers. Paleontological records place the genus in the river dolphin family Iniidae.