Species

BackActinella obserata (R.T. Lowe, 1852)

Actinella obserata (R.T. Lowe, 1852)

  • Kingdom: Animalia
  • Phylum:
  • Class: Mollusca
  • Order: Gastropoda
  • Family: Hygromiidae
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., Cuttelod, A. & Neubert, E.

Contributor/s:
Teixeira, D.

Facilitators / Compilers/s:


Assessment Rationale:

The species was listed as Vulnerable in 1994, based on Wells and Chatfield (1992). It was given a revised listing as Near Threatened in 1996, based on the same data-set. Since the Walden's surveys in 1970's there has been little new data on this species in spite of extensive survey work in the last known region on the island.  Seddon (2008) suggested the species should now be considered as Data Deficient (version 3.1) due to the lack of recent records. However based on the presence at a single location on the south coast of Madeira in a region where there has been substantial changes to habitats in the last 40 years, then using the precautionary principle, the species is now listed as Critically Endangered (CR) B2ab(iii) rather than Data Deficient. 

Geographic Range:

This species is endemic to Madeira. It is recorded from a single site on the south side of the island, close to Funchal (Seddon 2008).  There are been very few records of the Actinella fausta group of species (A. robusta, A. obserata, A. carinofausta, A. fausta) on the southern coast of Madeira, since Walden (1983) published his checklist where he suggested that there were several taxa with 'A. fausta'.

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

Population:

There are no data on population trends, although the species is believed to be rare.

Habitat and Ecology

It is believed to be present on ground and under stones in shrubby/grassland areas, but further research required to confirm the habitats.

Major Threat(s):

The major threat in this part of Madeira is encroaching urbanisation, as well as the construction of an infrastructure to service these towns and villages.  The region had been extensively modified with agriculture, hotel construction and urbanisation since Wollaston visited the island in the 1870's.

Conservation Actions

There are been very few records of the Actinella fausta group of species (A. robusta, A. obserata, A. carinofausta, A. fausta) on the southern coast of Madeira, since Walden (1983) published his checklist where he suggested that there were several taxa with 'A. fausta'. Research is needed to establish the taxonomy and distribution of this species on the island and to make a revised conservation assessment with suggested conservation actions.