IUCN SSC Mid-Atlantic Island Invertebrates Specialist Group

Species

Back • Caseolus innominatus (J.E. Gray, 1825)

Caseolus innominatus (J.E. Gray, 1825)

  • Kingdom: Animalia
  • Phylum:
  • Class: Mollusca
  • Order: Gastropoda
  • Family: Hygromiidae
LC Least Concern
IUCN Red List Status:
  • EX
  • EW
  • CR
  • EN
  • VU
  • NT
  • LC
  • DD
  • NE

Countries of Occurrence:
Portugal - Madeira

Archipelago(s):
Madeira

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Assessor/s:
Seddon, M.B.

Reviewer/s:
Cameron, R., Groh, K., Cuttelod, A. & Neubert, E.

Contributor/s:
Abreu, C. & Teixeira, D.

Facilitators / Compilers/s:

Assessment Rationale:

This species is restricted to Madeiran islands where different subspecies are found on Madeira and Porto Santo. The range data combined are under 100km2, however the fairly widespread distribution, the number of locations, the presence in degraded habitat and the population abundance, suggest that the species is not highly threatened, and as such it is assessed as Least Concern (LC). There are two Quaternary fossil taxa, but data from Cameron et al. (2006) suggests that these were not extant within historical times, and hence these subspecies do not meet the criteria for IUCN Extinct (version 3.1).

Geographic Range:

Caseolus innominatus compactus (= C. compactus compactus) (Seddon 2008, Plate 25F Map 91). 
This subspecies is endemic to Madeira on the Pta da Sao Lourenco so it has an area of occupancy of 36 km2, but with more than 10 localities.
Caseolus innominatus portosanctanus (= C. compactus portosanctanus) (Seddon 2008, Plate 23F Map 159). 
This subspecies is endemic to Porto Santo where it is widespread at both ends of the island so it has an area of occupancy of 28 km2, but with more than 10 localities.

There are quaternary subspecies on both Madeira and Porto Santo, that are also listed as parts of the species however, the data from Cameron et al. (2006) suggests that these were not extant within historical times, and hence do not meet the criteria for IUCN Extinct (verson 3.1).

Regions:
Portugal - Madeira
Extent of Occurrence (EOO):
(km2)
Area of Occupancy (AOO):
(km2)
Elevation Lower Limit:
(m)
Elevation Upper Limit:
(m)
Biogeographic Realms:
Palearctic
Presence:
Extant
Origin:
Endemic Madeira
Seasonality:
Resident

Population:

This species is thought to be stable.

Habitat and Ecology

Caseolus innominatus compactus is found on the underside of stones on rocky and grassy slopes.
Caseolus innominatus portosanctanus is found on the underside of stones on slopes and at base of crags.

Major Threat(s):

The species is locally abundant, and although there are declining quality of habitats in some parts of the range, the species seems able to tolerate some disturbance, and hence at present these declines are not impacting the species.

Conservation Actions

This species is widely distributed on the eastern peninsula of Madeira and Porto Santo, so 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.
Taxonomic actions include the examination of the two different subspecies to determine that the species limits are correctly identified.