Species

BackAtlantica guerinianus (Lowe, 1852)

Atlantica guerinianus (Lowe, 1852)

Madeiran Land Snail

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

Countries of Occurrence:
Portugal - Madeira

Archipelago(s):
Madeira

Reviewer/s:
Neubert, E. & Allen, D.J.

Contributor/s:

Facilitators / Compilers/s:


Assessment Rationale:

This species is endemic to the Madeira Island (Madeira Archipelago), where it was originally recorded from Riberia de Santa Luzia. It was originally listed as Possibly Extinct by Wells and Chatfield (1992) and Groombridge (1994). It was reassessed as Extinct in the 1996 list (Baillie and Groombridge 1996) as the species has not been recorded since the 1860s, despite intensive searching by different field researchers between 1970s and 1990s. Although Cameron claimed to have rediscovered the species, his records were found to belong to another taxon. The species is now assessed as Critically Endangered (Possibly Extinct). Habitat monitoring is required at the site to ensure that the present threats are not currently impacting the species.

Geographic Range:

This species is endemic to the Madeira Island (Madeira Archipelago), where it was originally recorded from Riberia de Santa Luzia (Wollaston 1878, Seddon 2008). Other surveys failed to find further sites for this species, despite intensive efforts between the 1970s and the 1990s (Seddon 2008). Teixiera (pers. comm. 2016) has failed to relocate the species in surveys over the last 16 years. The two records listed by Cameron and Cook (1999) from two sites, one of them close to Ponta do Pargo and the other one near Paul do Mar, have now been reassigned to other species (Cameron, pers. comm. 2016). 

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

Population:

After 140 years since its original description, the species has never been found, and is regarded as probably extinct.

Habitat and Ecology

In 1878, Wollaston described the habitat as deep wooded ravines under stones and leaf litter, in intermediate to high elevations. Between 1878 and present, there have been no records of this species, and it has been believed to be extinct. The localities where the species was found (Ribeiro Frio, Ribeiro Faial and Sao Jorge) have changed considerably since the discovery of the species.

Major Threat(s):

Urban expansion and tourist pressure may have had a significant effect on the species.

Conservation Actions

The species is on the EU Habitats and Species Directive Annex II and requires a Special Protection Area (SPA), however, it is thought to be extinct. There are few protected areas in the range of this species, and the establishment of a small area would benefit the species through reduction of the impact of tourism development. Habitat monitoring is required at the site to ensure that the present threats are not currently impacting the species.