South Asian river dolphin display the variances needed to support their classification as separate species. Thus, at present, a single species with two subspecies is recognized in the genus "Platanista", "P. g. gangetica" (Ganges river dolphin) and "P. g. minor" (Indus river dolphin). An assessment of divergence rates in mitochondrial DNA of the two subspecies indicates that they diverged from a common ancestor around 550,000 years ago. This ancestor is thought to have been a marine Platanistid inhabiting the epi-continental seas in South Asia during the sea level rises in the middle Miocene. The earliest fossil identified as belonging to the species is only
Endangered Species Act of 1973 legislation, crafting a document that completely changed the direction of environmental conservation in the United States. Dr. Bertrand is credited with writing the most challenged section of the Act, the "takings" clause – Section 2. The stated purpose of the Endangered Species Act is to protect species and also "the ecosystems upon which they depend." California historian Kevin Starr was more emphatic when he said: "The Endangered Species Act of 1982 is the Magna Carta of the environmental movement." The ESA is administered by two federal agencies, the United States Fish and Wildlife Service (FWS) and the National Marine Fisheries