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Bithynia pygmaea

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Taxonomy [top]

Kingdom Phylum Class Order Family
ANIMALIA MOLLUSCA GASTROPODA LITTORINIMORPHA BITHYNIIDAE

Scientific Name: Bithynia pygmaea
Species Authority: Preston, 1908
Synonym(s):
Gabbia pygmaea Preston, 1908
Taxonomic Notes:

Bithynia combines the two subgenera Gabbia and Digoniostoma. B. pygmaea belongs to the subgenera Gabbia.

Assessment Information [top]

Red List Category & Criteria: Data Deficient ver 3.1
Year Published: 2012
Date Assessed: 2010-07-26
Assessor(s): Richter, K. & Simonis, J.
Reviewer(s): Do, V., García, N., Tran, L. & Van Damme, D.
Justification:
This species has not been recorded since surveys done by Brandt and Temcharoen in the years between 1967 and 1970 and is considered Data Deficient. Further survey is required to determine its current range, population trend and ecological requirements.

Geographic Range [top]

Range Description: This species has a wide distribution in eastern Myanmar, and in central and northern Thailand (Phichit, Phetchabun, Nakhon Ratchasima (Tesana 2002), and Chiang Mai provinces) (Brandt 1974). There are also specimens known from Pahang State (Tepuyai River and the Mergau River; G.W. Davis, ANSP) in Peninsular Malaysia. The species has also been introduced to mainland north America (Perez et al. 2004). Research is needed to confirm the species' distribution.
Countries:
Native:
Malaysia (Peninsular Malaysia); Myanmar (Myanmar (mainland)); Thailand
Introduced:
United States
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population: No information available.
Population Trend: Unknown

Habitat and Ecology [top]

Habitat and Ecology: It is known from freshwater localities.
Systems: Freshwater

Use and Trade [top]

Use and Trade: No information available.

Threats [top]

Major Threat(s):

Until the 1980s the Mekong River flowed freely for ca. 5000 km from its source in Tibet to the coast of Viet Nam. The Mekong River passes through or by China, Myanmar, Lao PDR, Thailand and Cambodia. But since the 1980s the character of the river has been steadily transformed by dam-building programs in Yunnan province in China. Three hydroelectric dams are already in operation and two more are under construction due for completion in 2012 and 2017. Until 2030 there could be plans for at least two more dams. There are also eleven proposed dams on the mainstream of the Mekong below China. Even if no dams are built on the mainstream below China the dams in China will ultimately have serious effects on the functioning of the Mekong. It will alter the hydrology of the river and so the current ‘flood pulse’, the regular rise and fall of the river on an annual basis. The dams will block the flow of sediment down the river which plays a vital part in depositing nutrients on the agricultural regions flooded by the Mekong River. The dams will also lead to the erosion of river banks (Osborne 2009). Although the ecological effects of these dams on freshwater snails are poorly known, Temcharoen (1992) mentioned a negative effect on the snails caused by irregular fluctuation of the water level.

Water pollution due to the ongoing industrialisation in these developing countries may also be a threat to the freshwater snails of the Indo-Burma-Region (Temcharoen 1992).

Conservation Actions [top]

Conservation Actions: No information available.

Citation: Richter, K. & Simonis, J. 2012. Bithynia pygmaea. The IUCN Red List of Threatened Species. Version 2014.2. <www.iucnredlist.org>. Downloaded on 01 October 2014.
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