Bivalves, one of the major Mollusc groups, are largely Marine organisms, though many groups have invaded freshwater environments. Freshwater Razor Clams, Novaculina spp., are found in the rivers of South and Southeast Asia and the lower Yangtse basin in eastern China. There are currently three described species; Novaculina gangetica, which is found in the Ganges River basin in India and Bangladesh, and in the Kaladan and Lemro rivers in northwestern Myanmar, Novaculina siamensis is found in the Bang Pakong and Pasak rivers in Thailand, and the Mekong Delta in Vietnam, and Novaculina chinensis, which is known from the lower Yangtze River basin in eastern China.
In a paper published in the journal Scientific Reports on 5 November 2018, Ivan Bolotov and Ilya Vikhrev of the Northern Arctic Federal University and the Federal Center for Integrated Arctic Research of the Russian Academy of Sciences, Manuel Lopes-Lima of the Interdisciplinary Centre of Marine and Environmental Research and the Research Center in Biodiversity and Genetic Resources at the University of Porto, Zau Lunn and Nyein Chan of the Myanmar Program of Fauna & Flora International, Than Win of the Department of Zoology at Hpa-An University, Olga Aksenova, Mikhail Gofarov, Alexander Kondakov, and Ekaterina Konopleva, also of the Northern Arctic Federal University and the Federal Center for Integrated Arctic Research of the Russian Academy of Sciences, and Sakboworn Tumpeesuwan of the Department of Biology at Mahasarakham University, describe a new species of Freshwater Razor Clam from the Donthami and Ayeyarwady rivers in Myanmar.
The new species is named Novaculina myanmarensis, meaning ‘from Myanmar’. The species has an elongate oblong shell reaching 20.5–46.5 mm in length and 7.9–17.5 mm in height. The shell is comprised of white nacre (layered calcite and aragonite) covered by a light yellow to brown periostracum, the flesh of the body is pale yellow. Genetic analysis of the populations in the Donthami and Ayeyarwady rivers suggested that they shared a common ancestor in the Late Pleistocene, and a common ancestor with Novaculina gangetica in the Miocene (genetic material from Novaculina siamensis and Novaculina chinensis was not available for inclusion in the analysis).
The new species is named Novaculina myanmarensis, meaning ‘from Myanmar’. The species has an elongate oblong shell reaching 20.5–46.5 mm in length and 7.9–17.5 mm in height. The shell is comprised of white nacre (layered calcite and aragonite) covered by a light yellow to brown periostracum, the flesh of the body is pale yellow. Genetic analysis of the populations in the Donthami and Ayeyarwady rivers suggested that they shared a common ancestor in the Late Pleistocene, and a common ancestor with Novaculina gangetica in the Miocene (genetic material from Novaculina siamensis and Novaculina chinensis was not available for inclusion in the analysis).
Soft body morphology (right valve and corresponding mantle tissue were removed) and hinge
structure of Novaculina myanmarensis. Scale bar is 10 mm. Bolotov et al. (2018).
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