Distribution of freshwater Mollusca in Koothaippar wetland ecosystem Tiruchirappalli District Tamil Nadu

Freshwater Mollusca form an important animal group of the wetland ecosystems. The distribution and availability in terms of number of species needs scientific attention.  Present study is an attempt to document the available Molluscan forms in Koothaippar wetlands of Tiruchirappalli District. This study was carried out between summer 2013 to post-monsoon 2017. Nine species were recorded and among them 6 species belong to Gastropoda representing 2 orders, 3 families, 3 genera while 3 species were bivalves representing 1 order, 1 family and 2 genera. Bellamya bengalensis, Lamellidens marginalis and Pila globosa were the predominantly present molluscan fauna and are distributed throughout the year.  Five species of Molluscan fauna (Pila virens, Pila scutata, Bellamya dissimilis, Indoplanorbis exustus and Lamellidens corrianus) are less abundant and Parreysia favidens was found to be rare species of the ecosystem. These Molluscan forms, representing different families ranging from 34% of Ampullariidae, 33% of Unionoida, 22% of Viviparoidae and 11% of Planorbidae. Percent distribution of these shelled organisms indicate that they represent 3 orders viz., 56% of Architaenioglossa, 33% of Unionoida and 11% of Hygrophila.