Bellamya phthinotropis 

Scope: Global
Language: English

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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Mollusca Gastropoda Architaenioglossa Viviparidae

Scientific Name: Bellamya phthinotropis (Martens, 1892)
Bellamya unicolor ssp. phtinotropis Mandahl-Barth, 1954
Bellamya phtinotropis (Martens, 1892)
Vivipara phthinotropis Martens, 1892
Taxonomic Notes: This was considered as a subspecies of B. unicolor by Mandahl-Barth (1954) and re-instated as a distinct species by Brown (1994). With its large size and thin shell, it differes from all other Victorian viviparids. It must probably be lowered in taxonomic rank to 'ecotype' or at best 'subspecies', as all other 'endemic' Victorian Bellamya species (see Sengupta et al. 2009), but  B. phtinotropis was not included in their molecular analysis because, in spite of intense research in the type area (A. Jorgensen pers. comm. 2014), no live specimens were found.

Assessment Information [top]

Red List Category & Criteria: Critically Endangered (Possibly Extinct) B2ab(i,ii,iii) ver 3.1
Year Published: 2017
Date Assessed: 2015-10-24
Assessor(s): Van Damme, D. & Lange, C.
Reviewer(s): Seddon, M.B.
Facilitator/Compiler(s): Sayer, C.
Despite efforts to find this deep water morphotype, it has not been recovered since the 1950s. This species appears to have been already rare in the first half of the 20th century, represented by a few severely fragmented subpopulations respectively in the north and in the south of the lake. It has been recorded from four localities, within a maximum area of occupancy (AOO) of 10 km² based on available habitat, but the current number of known localities is zero. There is declining quality of benthic deep water habitats due to potential impacts from trawling, from pollution (e.g. sewage output from towns) and eutrophication from decay of water hyacinth rotting-down after cutting programmes (Lange 2010). It is therefore assessed as Critically Endangered and it is Possibly Extinct.
Date last seen: 1954
Previously published Red List assessments:

Geographic Range [top]

Range Description:This endemic morphotype was described from deeper waters (c. 10-33 m) of Lake Victoria. Originally discovered near 'Nyamagotso' near Uzindja (= Uzinza near Mwanza Gulf, Tanzania), at the southwestern side of the lake, it was subsequently also dredged in the mid-20th century at Buvuma Channel, at Hippo Bay at Entebbe, in Salisbury Channel (Uganda) and at Ilemera (south of Bukoba, Tanzania) (Mandahl-Barth 1954). However, during all later surveys, i.e. since the last decades of the 20th century, it has not been recorded and this form may have become extinct.
Countries occurrence:
Possibly extinct:
Tanzania, United Republic of; Uganda
Additional data:
Estimated area of occupancy (AOO) - km2:1-10
Number of Locations:1-4
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:Never have more than a few specimens been recovered during former surveys. Subpopulations are assumed to be small and strongly localised (occurring in a few, fragmented deep-water microhabitats) and therefore, the population is considered to be severely fragmented.
Current Population Trend:Decreasing
Additional data:
Population severely fragmented:Yes

Habitat and Ecology [top]

Habitat and Ecology:It is benthic, on muddy bottoms in deeper waters of Lake Victoria.

Use and Trade [top]

Use and Trade: This species is not used.

Threats [top]

Major Threat(s):

It has not been recorded since 1954. It may be extinct or near-extinct due to increasing hypoxic-anoxic conditions of the water column in deeper water as a result of eutrophication and pollution, and trawling.

Conservation Actions [top]

Conservation Actions: No specific conservation actions have been undertaken.

Errata [top]

Errata reason: This errata assessment has been published to remove a duplicated reference in the bibliography, and to correct some minor details in the reference Brown, 1994.

Amended [top]

Amended reason: Point locality records for this species were recently compiled by D. Van Damme. As a result of these records, there has been a slight extension to the previously published distribution range for this species. These point locality records are also now displayed on the distribution map.

Citation: Van Damme, D. & Lange, C. 2017. Bellamya phthinotropis (errata version published in 2017) (amended version of 2016 assessment). The IUCN Red List of Threatened Species 2017: e.T2750A121709613. . Downloaded on 19 June 2018.
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