Species

BackLeiostyla cassida (Lowe, 1831)

Leiostyla cassida (Lowe, 1831)

  • Kingdom: Animalia
  • Phylum:
  • Class: Mollusca
  • Order: Gastropoda
  • Family: Lauriidae
CR Critically Endangered
IUCN Red List Status:

Countries of Occurrence:
Portugal - Madeira

Archipelago(s):
Madeira

Assessor/s:
Seddon, M.B.

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

Contributor/s:

Facilitators / Compilers/s:


Assessment Rationale:

This species is endemic to the main island of Madeira. Wollaston (1878, p. 213) commented that it was found at several sites including Ribeira de Santa Luzia, Ribeira de Sao Jorge and Santa Anna. However there are no recent records of this species (Seddon 2008). There have been numerous surveys in the Ribeira de Santa Luzia and Ribeira de Sao Jorge in the last 30 years, some specifically looking for this species, but as yet, there are no recent records of this species (Seddon 2008). The habitats have been modified extensively since Wollaston collected the species in 1870, as these valleys all lie on the edge of urbanisations. Seddon (2008) proposed the species should be listed as IUCN Critically Endangered, Possibly Extinct as there are no recent records confirming the distribution. As there are remote areas on Madeira which are very inaccessible, there is a possibility that the species may still exist in a small pocket of suitable habitat, as other endemic species on the island have been refound after over 50 years without records.  

Geographic Range:

This species is endemic to the main island of Madeira. Wollaston (1878) commented that it was found at several sites including Ribeira de Santa Luzia, Ribeira de Sao Jorge and Santa Anna. However there are no recent records of this species (Seddon 2008). There have been numerous surveys in the Ribeira de Santa Luzia and Ribeira de Sao Jorge in the last 30 years, some specifically looking for this species, but as yet, there are no recent records of this species (Seddon 2008). The habitats have been modified extensively since Wollaston collected the species in 1870, as these valleys all lie on the edge of urbanisations.

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

Population:

Not possible to establish trends, as the species declined in 1870s. There have been numerous surveys since 1970, at many different points on the island, over different seasons using different sampling methodologies, and as yet the species has not been located.

Habitat and Ecology

Two of the valleys lie on the edge of urbanisations and so the habitats have been modified since 1878, with only small remants of Laurisilva forest remaining.

Major Threat(s):

The major threats to the species were loss of habitat, as much of the forest on the south coast where the species may have been found has been changed to agricultural land, plantations, urban developments and residential gardens.

Conservation Actions

This species is listed on the EU Habitats and Species Directive Annex II and the Council of Europe Bern Convention Appendix 2. Further survey work on the south coast in remote ravines to determine if the species is still extant.