ISSN 0738-9388 221 Volume: 48 THE FESTIVUS ISSUE 4 Checklist of Freshwater Mollusca (Gastropoda and Bivalvia) Recorded from the Buriganga and Turag Rivers, Dhaka, Bangladesh Mohammad Abdul Baki, Md. Muzammel Hossain* and Naser Ahmed Bhouiyan Department of Zoology, Jagannath University, Dhaka-1100, Bangladesh * Corresponding author’s email: muzammel3@gmail.com ABSTRACT Freshwater mollusks have received little attention from conservation scientists. We collected museum records and conducted an inventory of freshwater mollusks to develop a species checklist for the Buriganga and Turag Rivers. The study area extended from the Posthoghola Bridge (90°26T2" E and 23°40'25"N), Buriganga River to the Tangi Bridge, Turag River (90°24'29"E and 23°53'59"N). Surveys were conducted every two weeks from December 2012 to November 2013 in both rivers. During the survey period we collected mollusks by hand picking. A total of 17 species belonging to 8 families (Ariophantidae, Viviparidae, Pilidae, Thiaridae, Lymnaeidae, Unionidae, Cyrenidae and Solecurtidae) were identified from both rivers. Among the 17 species, 14 were identified in the Buriganga River and 12 species were found in the Turag River. Corbicula fluminea (O. F. Muller, 1774), Lymnaea luteola (Lamarck 1822) and Macrochlamys sequax (Benson, 1859) were found in the Buriganga River and Bellamy a dissimilis (Muller, 1774), Paludomus conica (Gray, 1834) and Novaculina gangetica (Benson, 1853) were found in the Turag River. Muddy, sandy and stony benthic and littoral habitats were observed in both rivers. It is our hope that this study will stimulate additional mollusk research in thisarea. KEY WORDS Freshwater Mollusca, Buriganga and Turag Rivers. INTRODUCTION Freshwater mollusks (Gastropod: Snails; Mussels: Bivalvia and Unionoida) are an important component of many healthy river ecosystems. In addition, freshwater mollusks often are used by various agencies to monitor environmental quality, including trends of chemical contamination (Rosenberg and Resh 1993; Supian & Ikhwanuddin, 2002). Mollusks are one of the most threatened major taxonomic groups worldwide, comprising 42% of all species extinctions (Lydeard et al, 2004). Within this group, the freshwater mussels of the order Unionoida are highly threatened throughout their distribution (Bogan 1993). Today, the numbers of threatened species and species extinctions have increased at an alarming rate (Baillie et al, 2004; Lydeard et al., 2004). Humans, directly or indirectly, are largely responsible for these species losses (Wilson 1989). Freshwater mollusks have been affected by both extrinsic factors such as habitat destruction, land-use practices, water pollution, reduction or loss of host plant and/or organisms like fish or substrates, and intrinsic characters such as growth and reproduction, which evolve in close relation with habitats (Steams 1992; Petts et al., 1993; Richter et al., 1997; Primack 2002). One interesting intrinsic character is that of life span. Long-lived species generally grow slowly and have delayed maturity and low fecundity. Thus, long-lived species may tolerate short-term fluctuations in the environment, but if population numbers are severely reduced.