IUCN SSC Mid-Atlantic Island Invertebrates Specialist Group


BackLeiostyla degenerata Wollaston, 1886

Leiostyla degenerata Wollaston, 1886

  • Kingdom: Animalia
  • Phylum:
  • Class: Mollusca
  • Order: Gastropoda
  • Family: Lauriidae
NT Near Treatened
IUCN Red List Status:

Countries of Occurrence:
Portugal - Madeira


Seddon, M.B.

Cameron, R., Groh, K., Cuttelod, A. & Neubert, E.

Cameron, R.

Facilitators / Compilers/s:

Assessment Rationale:

This species was previously regarded as a candidate for IUCN status Endangered B1ab(iii)+2ab(iii) (version 3.1) as it is only known from a small region of Porto Santo, around the summit areas of the mountains, and, in the past, there was some evidence of declining habitat quality due to agricultural change which merits higher listing than Vulnerable D2 (Seddon 2008). However, most recent visits to the island show that since the area of Pico Branco was designated a protected area, the threats have now been removed (Cameron, pers. comm., 2010), and as a consequence the species is now considered to be Near Threatened (NT).

Geographic Range:

This species is endemic to Porto Santo on the north slopes of Pico Branco in an area about three km by two km (Seddon 2008). No fossil material has been found of this species (Cameron et al. 2006).

Portugal - Madeira
Extent of Occurrence (EOO):
Area of Occupancy (AOO):
6 (km2)
Elevation Lower Limit:
Elevation Upper Limit:
Biogeographic Realms:
Endemic Madeira


There are no recent data to establish population trends, but it is believed to be stable.

Habitat and Ecology

This species was found in the crevices and in the leaf-litter on the rock ledges; Leiostyla monticola and Leiostyla calathiscus were living in the same habitat (Seddon 2008).

Major Threat(s):

There are no current threats following the designation of the region as a protected area. Although fire is a possible threat, it probably would not impact the species over the entire area, given the presence on rock crags and in fissures.

Conservation Actions

Since the area of Pico Branco was designated a protected area, the threats have now been removed (Cameron, pers. comm., 2010), however the species would benefit from a non-sampling based monitoring programme to establish future trends and re-occurrence of threats.