| Kingdom | Phylum | Class | Order | Family |
|---|---|---|---|---|
| ANIMALIA | MOLLUSCA | GASTROPODA | LITTORINIMORPHA | HYDROBIIDAE |
| Scientific Name: | Bythinella dunkeri |
| Species Authority: | (Frauenfeld, 1857) |
| Taxonomic Notes: | This species was reviewed by Benke et al. (2009), and found to be one of a series of species clusters, Clade IV, which they placed with B. bicarinata. Some populations listed as cf. dunkeri, on shell morphology were placed in Clade III. This differs slightly from Bichain et al. (2007) analysis of mtDNA COI and nDNA ITS1 sequence data showed that the "typical" two-keeled Bythinella bicarinata are actually part of a clade widespread in central to north-eastern France and nearby regions. Consequently, Bythinella dunkeri as well as 3 other range restricted species in France (Bythinella lalindei, Bythinella moulinsii and Bythinella pujolensis) were provisionally treated as junior synonyms of Bythinella bicarinata. Given that Benke et al. (2009) have a population in one clade that was different to the population placed in the B. bicarinata clade, then data should be reviewed from all subpopulations before the species is fully synonymised, as these are further from the other subpopulations geographically and being most distinct morphologically from the keeled populations, so they may be kept as subspecies. |
| Red List Category & Criteria: | Data Deficient ver 3.1 | ||||||
| Year Assessed: | 2011 | ||||||
| Assessor/s: | Prie, V. & Bichain, J. | ||||||
| Reviewer/s: | Seddon, M., von Proschwitz, T. & Nichols, C. | ||||||
|
Justification: This species was previously assessed as "Vulnerable B1 + 2c" (Mollusc Specialist Group 1996) based on a restricted range species threatened by water pollution. However the taxonomic status is under review, as there is evidence to suggest that these populations may be conspecific with a more widespread species, B. bicarinata, a species described from central France. Given that Benke et al. (2009) have a subpopulation in one clade that was different to the subpopulation placed in the B. bicarinata clade, then data should be reviewed from all subpopulations before the species is fully synonymised, as these are further from the other subpopulations geographically and being most distinct morphologically from the keeled populations, so they may be kept as subspecies. The species should be reassessed as Data Deficient (DD) pending review of the status of the populations. If shown to be part of B. bicarinata, then it will take the oldest available name and be assessed as Least Concern. |
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| History: |
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| Range Description: | This species is now known to range from France, Germany, Luxembourg, Netherlands and Belgium. In 1996 it was considered to have a range of Belgium and Germany. Falkner et al. (2002) list it for France. |
| Countries: |
Native:
Belgium; France (France (mainland)); Germany; Luxembourg; Netherlands
|
| Population: | There is no recent data on population trends, but as it is widespread it is assumed to be stable. |
| Population Trend: |
Stable
|
| Habitat and Ecology: | This species is found in small streams, rivers and springs, and is one of the most widespread Bythinella species in terms of its habitat requirements. |
| Systems: | Freshwater |
| Major Threat(s): | Originally viewed as a restricted range species threatened by water pollution (mainly from nitrates and pesticides from agricultural sources and some domestic pollution), the threats still apply, although the species is now known from a wider range. |
| Conservation Actions: | The species needs further taxonomic review in light of the recent research showing that it maybe conspecific with other species. |
| Citation: | Prie, V. & Bichain, J. 2011. Bythinella dunkeri. In: IUCN 2011. IUCN Red List of Threatened Species. Version 2011.2. <www.iucnredlist.org>. Downloaded on 08 February 2012. |
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