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 occurred by 1963 to habitat preservation instead of take regulations. A provision was added by Congress in the Land and Water Conservation Fund Act of 1965 that provided money for the "acquisition of land, waters...for the preservation of species of fish and wildlife that are threatened with extinction." The predecessor of the ESA was the Endangered Species Preservation Act of 1966 (P.L. 89-669 ). Passed by Congress, this act permitted the listing of native U.S. animal species as endangered and for limited protections upon those animals. It authorized the Secretary of the Interior to list endangered domestic fish and wildlife