IUCN SSC Mid-Atlantic Island Invertebrates Specialist Group


BackMesiotelus maderianus Kulczynski, 1899

Mesiotelus maderianus Kulczynski, 1899

  • Kingdom: Animalia
  • Phylum: Arthropoda
  • Class: Arachnida
  • Order: Araneae
  • Family: Kulczynski, 1899
EN Endangered
IUCN Red List Status:

Countries of Occurrence:
Portugal - Madeira


Luis Crespo
Mario Boieiro
Paulo A.V. Borges
Pedro Cardoso
Cardoso, P., Crespo, L.C., Silva, I., Borges, P. & Boieiro, M.

Henriques, S. & Russell, N.


Facilitators / Compilers/s:

Assessment Rationale:

Mesiotelus maderianus is known from high-altitude laurisilva forest and above tree-line on Madeira Island, Portugal. This species has a restricted geographic range, with a maximum estimated extent of occurrence (EOO) and area of occupancy (AOO) of ca700 km². Wildfires might have negatively impacted the subpopulations above treeline in the past and may do it again in the future. Based on this threat and because a single wildfire event may affect the entire area above tree-line, the species occurs at only two locations and there is a continuing decline in the area and quality of habitat. However, the forest areas are in general not threatened. Mesiotelus maderianus is therefore assessed as Endangered (EN). More research is needed into the distribution, ecology and threats and a monitoring of population and habitat trends should be conducted to confirm species status.

Geographic Range:

Mesiotelus maderianus is known from few sites at high altitude, in laurisilva forest or above treeline on Madeira Island, Portugal. There are only three records for the species, mostly old (KulczyƄski 1899) plus a new record from Pico do Cidrão (unpublished). We still performed species distribution modelling to predict its potential range with confidence limits, although these should be taken with caution (Cardoso et al. 2017). The extent of occurrence (EOO) and the area of occupancy (AOO) are estimated to be between 28-720 km².

Portugal - Madeira
Extent of Occurrence (EOO):
28-720,256 (km2)
Area of Occupancy (AOO):
28-720,256 (km2)
Elevation Lower Limit:
650 (m)
Elevation Upper Limit:
1850 (m)
Biogeographic Realms:
Endemic Madeira


No population size estimates exist, but the population is inferred to be declining due to the loss of habitat.

Habitat and Ecology

The only records of the species are from both laurisilva (Queimadas) and the mountain peaks (Pico do Cidrão). Mesiotelus maderianus is an active ground hunter feeding mainly on small size arthropods.


Major Threat(s):

Although the laurisilva areas are extensive and mostly well preserved, the mountain areas above the tree-line have suffered recent (2010) extensive wildfires that destroyed much of the native habitat. It is unknown whether these events have affected the species and to what proportion of its range, although this can be inferred.

Conservation Actions

No specific conservation measures are in place for this species, but most of the species range is predicted to be inside the Madeira Natural Park. Given the high uncertainty the species range should be extensively studied. Furthermore, studies on the ecology of the species and how it was affected by wildfire is necessary. Afterwards, monitoring of population and habitat trends should be conducted to confirm species status.