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 Endangered Species Act of 1973 The Endangered Species Act of 1973 (ESA; 16 U.S.C. § 1531 et seq.) is one of the few dozens of US environmental laws passed in the 1970s, and serves as the enacting legislation to carry out the provisions outlined in The Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). Designed to protect critically imperiled species from extinction as a "consequence of economic growth and development untempered by adequate concern and conservation", the ESA was signed into law by President Richard Nixon on December 28, 1973. The U.S. Supreme Court found