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Bythinella eutrepha 

Scope: Global, Europe & Mediterranean
Language: English
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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Mollusca Gastropoda Littorinimorpha Hydrobiidae

Scientific Name: Bythinella eutrepha (Paladilhe, 1867)
Taxonomic Notes: Originally regarded as a subspecies, Falkner et al., 2002 followed Bernasconi (2000), who separated this taxa from Bythinella cebennensis (Dupuy 1851).  Falkner et al., 2002 also placed Paludinella anianensis (Paladihle 1870) as a synonym of this species. Material from the Paladilhe collection is polytypic (V. Prie pers. comm. 2009): the shells from the Herault basin seem to belong to B. eurystoma, while the shells from the River Lez seem to  belong to a different species. Bythinella eutrepha should then be considered as a distinct species endemic to the Lez drainage.

Assessment Information [top]

Red List Category & Criteria: Critically Endangered (Possibly Extinct) B1ab(ii,iii) ver 3.1
Year Published: 2010
Date Assessed: 2009-05-27
Assessor(s): Prie, V.
Reviewer(s): Gargominy, O., Bouchet, P. & Cuttelod, A.
Contributor(s): Bichain, J.
Justification:
Bythinella eutrepha is endemic to France. It has a restricted range, as it is only found in one spring system, where it is threatened by encroachment from the town of Montpellier. The species is considered as Critically Endangered, Possibly Extinct B1ab(ii,iii), as it has not been found in recent years (V. Prie pers. comm. 2009).  The EOO is estimated as 49 km2, based on observed data from two sites, both fed by the same groundwater source. There are no records in northern part of the Lez catchment, despite active recording, and no records in southern part, which contains Montpellier, and hence little pristine habitat.

Geographic Range [top]

Range Description:This species is endemic to France, where it was originally described from floodline debris of the river Lez (Department Herault) It is considered to be endemic to the Lez drainage basin. Falkner et al. (2002) suggested three possible sites; the resurgences along the bed of the River Lez, springs at Cauquillade, Aniane, Department Herault; Moulin de St Guilherm-le-Desert. This species is possibly extinct, as it has not been found in recent years (V. Prie pers. comm. 2009).  The EOO is estimated as 49 km2, based on observed data from two sites, both fed by the same groundwater source.  There are no records in northern part of the Lez catchment, despite active recording, and no records in southern part, which contains Montepellier, and hence little pristine habitat.
Countries occurrence:
Possibly extinct:
France (France (mainland))
Additional data:
Estimated area of occupancy (AOO) - km2:49Continuing decline in area of occupancy (AOO):Yes
Estimated extent of occurrence (EOO) - km2:49
Number of Locations:1
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:There is no population data available for this species, but it is suspected to be now extinct.
Current Population Trend:Unknown
Additional data:
Population severely fragmented:No

Habitat and Ecology [top]

Habitat and Ecology:According to Falkner et al. (2002), B. eutrepha should be restricted to the Lez catchment, where it was living in subterranean waters.
Systems:Freshwater
Continuing decline in area, extent and/or quality of habitat:Yes

Threats [top]

Major Threat(s): The main threat is from urban encroachment leading to decline in quality of habitat, but other threats in part of the range include water pollution from vineyards (pesticides and herbicides), water pollution from domestic sources (sewage and run-off) and water abstraction for domestic and agricultural purposes.

Conservation Actions [top]

Conservation Actions: No conservation actions in place, but part of the range lies within a Natura 2000 site, which should ensure water quality is maintained. More research is needed on taxonomy,  population tends and threats.

Citation: Prie, V. 2010. Bythinella eutrepha. The IUCN Red List of Threatened Species 2010: e.T155832A4851241. . Downloaded on 24 September 2018.
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