New Records of Two Non-native Clam Species (Bivalvia: Cardiidae) from the Coastal Waters of Bangladesh

Benthic suspension feeders, such as many marine bivalve molluscs, influence the nutrient and organic cycles of benthic and pelagic systems through their ability to filter a wide size range of particles and deposit organic matters that sink to the bottom. They also play important roles in coastal and marine ecosystems by filtering the water and serving as habitat and prey for a variety of sea life. Due to the increasing trends of environmental contaminations in recent years, many bivalves have been using as a potential biomarker for assessing the worse environment. Moreover, the shell of a bivalve is comprised of calcium carbonate, which may support thousands of calciferous organisms into the water body. Mostly, bivalves inhabit the tropics, as well as temperate and boreal waters, and they can survive and even flourish in extreme environmental conditions like Bangladesh. Nowadays, many bivalve molluscs have been identified as a superior source of bioactive compounds and are using for pharmaceutical and nutraceutical purposes as well as other applications. However, until now, few systematic studies on marine bivalve molluscs have been conducted through which a total of 437 marine and brackish water species were identified and recorded in Bangladesh. But still, our knowledge of taxonomy and systematic on marine molluscs are primitive in the context of the country. Here we report two new species of bivalve molluscs, Parvicardium exiguum and Trachycardium procerum belonging to the family Cardiidae, from the Kutubdia Island of Bangladesh. The study added these two bivalve species, which has not been recorded from the coastal zone of Kutubdia Island during the previous studies. To sum up, studies and survey on taxonomy and systematics in marine bivalves will provide new dimensions for further research about these important marine invertebrates.