Caseolus calculus 


Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Mollusca Gastropoda Stylommatophora Hygromiidae

Scientific Name: Caseolus calculus
Species Authority: Lowe, 1854
Common Name(s):
English Madeiran Land Snail

Assessment Information [top]

Red List Category & Criteria: Vulnerable D2 ver 3.1
Year Published: 2013
Date Assessed: 2010-09-24
Assessor(s): Seddon, M.B.
Reviewer(s): Groh, K., Cameron, R., Cuttelod, A. & Neubert, E.
Contributor(s): Teixeira, D. & Cameron, R.
This species was previously listed as Vulnerable (VU) D2 (version 2.3;  IUCN 1996), the latest evaluation suggests it could meet the criteria for Endangered  (EN) B1ab(iii) or Vulnerable (VU) D2 (version 3.1) depending on the severity of threats to these locations.  All recent records are only from three locations; the populations on Pico Branco and Ilhau de Cima are the safest, as there is no possibility of building development.  The third location on the mainland is most susceptible, from habitat loss from coastal erosion or habitat degradation due to invasive species (plants), fire or tipping or loss of populations due to introduced rodents. Given the maintained presence in low density at the three locations, the species should be maintained as Vulnerable (VU) D2.
Previously published Red List assessments:
1996 Vulnerable (VU)
1994 Vulnerable (V)
1990 Vulnerable (V)
1988 Vulnerable (V)
1986 Vulnerable (V)
1983 Vulnerable (V)

Geographic Range [top]

Range Description: This species is endemic to Madeiran islands where it is only known from Porto Santo, around Pico Branco, the southeast end of the island and the Ilhau de Cima (Seddon 2008) with similar distribution since 1878 (Wollaston 1878). Recent records (Field records 1984-1998) confirm the species is still living in all these locations.
Countries occurrence:
Portugal (Madeira)
Estimated area of occupancy (AOO) - km2: 12
Number of Locations: 3
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population: Populations have been small since 1880's, although there is a possible decline of the mainland populations.
Current Population Trend: Stable
Additional data:

Habitat and Ecology [top]

Habitat and Ecology: Caseolus calculus lives at the base of grasses and herbs and on rocky slopes.
Systems: Terrestrial
Continuing decline in area, extent and/or quality of habitat: No

Use and Trade [top]

Use and Trade: The species is not known to be utilised, although occasionally sold by shell collectors.

Threats [top]

Major Threat(s): The population on the mainland coastal area is most susceptible, from habitat loss from coastal erosion or habitat degradation due to invasive species (plants), fire or tipping or loss of populations due to introduced rodents.

Conservation Actions [top]

Conservation Actions: This species is listed on the EU Habitats and Species Directive Annex II and the Council of Europe Bern Convention Appendix 2. Recommended conservation actions include management of the protected areas for maintenance of this species and monitoring of the protected areas to ensure no loss of further habitat and subpopulations.

Citation: Seddon, M.B. 2013. Caseolus calculus. The IUCN Red List of Threatened Species 2013: e.T3990A10279573. . Downloaded on 26 November 2015.
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