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Leptaxis wollastoni 

Scope: Global
Language: English
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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Mollusca Gastropoda Stylommatophora Hygromiidae

Scientific Name: Leptaxis wollastoni (R.T. Lowe, 1852)
Taxonomic Notes: Seddon (2008) reported that Wollaston (1878) and Walden (1983) noted that var. subdubia is apparently intermediate between L. wollastoni and L. nivosa; both authors nonetheless treated wollastoni as a distinct species. The intermediate is only found on a very small area on Pico do Concelho, whereas in most parts of their ranges the two species are clearly and distinctly separable. The subfossil shells from the Quaternary deposits below Pico do Concelho are larger than the living shells.

Two different subspecies are recognised by some authors: Leptaxis wollastoni forensis (Wollaston, 1878).
Mandahl-Barth(1950) treated  the population of this islet (Islet of Ilheu de Fora off its eastern coast) as a distinct subspecies.

Assessment Information [top]

Red List Category & Criteria: Endangered B1ab(iii,v)+2ab(iii,v) ver 3.1
Year Published: 2011
Date Assessed: 2010-08-31
Assessor(s): Seddon, M.B.
Reviewer(s): Groh, K., Cameron, R., Cuttelod, A. & Neubert, E.
Justification:
This species is restricted to two locations, Pico do Conchelo on Porto Santo and Ilheu de Fora, with an area of occupancy of under 12 km2.  At both sites it is vulnerable to predation by introduced rodents, as well as changes in grassland management and burning.  On the mainland threats of disturbance from tourism developments have been reported (Craze, pers. comm., 2006), however this area is now partly protected which will minimise further impacts.

Seddon (2008) proposed the species should be assessed as Endangered B2ab(iii), an assessment confirmed by the evaluators, with comments that each subspecies (subpopulation) merits an assessment as Critically Endangered, and that the decline in mature individuals, provides a revised assessment as Endangered B1ab(iii,v)+2ab(iii,v).
Previously published Red List assessments:

Geographic Range [top]

Range Description:This species is endemic to the Madeiran archipelago; it is restricted to the eastern part of the island of Porto Santo where it is found in two locations, one on an off-shore islet (Fora) and one on the mainland on Pico do Concelho (Seddon 2008, p. 83).  Each subpopulation is considered to be a separate subspecies by Mandhal-Barth (1950).
Countries occurrence:
Native:
Portugal (Madeira)
Additional data:
Estimated area of occupancy (AOO) - km2:12
Number of Locations:2
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:The species is not common in the area on Pico do Concelho. It is is quite small, and other species of Leptaxis (L. nivosa), tend to be more dominant.
Current Population Trend:Unknown
Additional data:
Continuing decline of mature individuals:Yes

Habitat and Ecology [top]

Habitat and Ecology:This species is found in open grassland under rocks and in rocky areas on the eastern summit of Pico do Concelho.
Systems:Terrestrial
Continuing decline in area, extent and/or quality of habitat:Yes

Use and Trade [top]

Use and Trade: There is no known trade in this species, although shells are occasionally offered by shell dealers.

Threats [top]

Major Threat(s):

This species is vulnerable to predation by introduced rodents and changes in grassland management and burning. 

Conservation Actions [top]

Conservation Actions: Habitat monitoring for impact of grassland management changes, recreational activity or fires on the species habitat and possible impact of predators (rodents) on this species are recommended.

Citation: Seddon, M.B. 2011. Leptaxis wollastoni. The IUCN Red List of Threatened Species 2011: e.T11655A3300335. . Downloaded on 24 June 2018.
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