Page last updated
11 November 2014
Unionoida cum Grano Salis
The Indotropical Region extends from the Pei River in China south through Indochina to Indonesia, and west to include India. A total of 219 species are known from the region in three families: Unionidae, Margaritiferidae and Etheriidae. The Indotropical Region ranks second in species richness after Nearctica.
The Intropical Region is subdivided into four distinct subregions, each with a characteristic freshwater mussel assemblage. The Yangtze-Huang Subregion (IN1; 67 spp.) covers the basins from the Pei River south to the Qiantang, as well as Taiwan. The area from southern China to the Salween, including the Mekong, is the Indochina Subregion (IN2; 82 spp.). The India-Burma Subregion (IN3; 58 spp.) extends from the Irrawaddy in the east to the Indus on its western frontier. The larger islands of Indonesia and the Philippines we group as the Sunda-Philippines Subregion (IN4; 32 spp.). New Guinea is part of the Australasian Region, and Sulawesi does not seem to have any freshwater mussels.