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
St. Pierre Island of "Casuarina equisetifolia" trees up 12 m (40 ft) high on its northwestern part, covering a third of the land area. The trees were originally planted as windbreak for the mining camp, and have unexpectedly thrived and spread. Most of the plant species once found on St Pierre are now gone, including the "Pisonia", Suicide Tree ("Cerbera odollam") and rosemallow ("Hibiscus tiliaceus"). Some "Pemphis acidula" might persist. By about 1960, it was noted that the most common herbaceous plant was "Stachytarpheta indica", while the introduced Indian Blanketflower ("Gaillardia pulchella") had established itself widely. Sisal ("Agave sisalana"), Chinese tiolet ("Asystasia gangetica"),