IUCN SSC Mid-Atlantic Island Invertebrates Specialist Group


BackPhthiracarus atlanticus (Pérez-Íñigo, 1987)

Phthiracarus atlanticus (Pérez-Íñigo, 1987)

  • Kingdom: Animalia
  • Phylum: Arthropoda
  • Class: Arachnida
  • Order: Acari: Oribatida
  • Family: Phthiracaridae
DD Data Deficient
IUCN Red List Status:

Countries of Occurrence:
Portugal - Azores


Russell, N.


Facilitators / Compilers/s:

Assessment Rationale:

Phthiracarus atlanticus is an endemic species of the Azores (Portugal), known from Terceira and Sta. Maria. From the available data, it potentially has a small Extent of Occurrence (244 km2 ) and Area of Occupancy (24 km2 ), which are likely to be underestimates, as this species probably has a wider distribution through the soil component of the islands. It can be assumed, however, that this species is affected by human activities and invasive plant species that alter the natural structure and composition of the soil. Future climatic changes and increased risk of droughts will also affect this species. The present situation of this species needs to be further assessed and further research is needed into its population, distribution, threats, ecology and life history; while conservation of natural habitats and invasive species control could potentially aid this species' conservation. Based upon the incomplete knowledge regarding this species' population, distribution, threats and ecology, it is not possible to accurately estimate the extinction risk of the species and it could theoretically fall into any category. Therefore, this species is assessed as Data Deficient (DD). 

Geographic Range:

Phthiracarus atlanticus is an Azorean-endemic oribatid mite species known from Terceira and Sta. Maria islands (Azores, Portugal) (Borges et al. 2010). It is known only from a few sites, but is present in the Natural Forest Reserves of Pico Alto (Sta. Maria). From the available data, the Extent of Occurrence (EOO) could be ca. 244 km² and the Area of Occupancy (AOO) could be 24 km².

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


No current population size estimates exist for this species. As an oribatid mite, this species in likely common and widespread in the soil habitat. Current Population Trend:  Unknown

Habitat and Ecology

The ecology and traits of this species are unknown. Oribatid mites are associated with organic matter in most terrestrial ecosystems, being found throughout the soil profile, in surface litter, on grasses, shrubs or in the bark and leaves of trees, among other habitats. Oribatida are also one of the most numerically dominant arthropod groups in the organic horizons of most soils (Behan-Pelletier 1999). Phthiracarus atlanticus specimens were collected in the soil, under leaf litter, both under native and introduced vegetation (Erica azorica, Picconia azorica, Viburnum tinus, Hedychium gardnerianum, Pittosporum undulatum and Acacia sp.) Systems:  Terrestrial

Major Threat(s):

A lack of information regarding the present range of this species precludes an assessment of potential threats. Nevertheless, it can be assumed that this species will be affected by future habitat declines as a consequence of climate change (Ferreira et al., 2016) and increased droughts. This species has been found in areas of native vegetation, but also in disturbed areas. Other factors that degrade habitat quality, like changes in the soil structure and composition, namely land use changes, agricultural practices, pesticides and nutrient loads or invasive plants might also affect this species. 

Conservation Actions

The species is not protected by regional law, but part of its habitat is in regionally protected areas (Natural Parks of Terceira and Sta. Maria). Besides climate change and increased risk of droughts, land-use changes and invasive species are likely to be the main current and future threats faced. As such, conservation of native habitats and invasive species control could potentially aid this species' conservation. Further research is needed into its population, distribution, threats, ecology and life history, and it is also necessary to develop a monitoring plan for the invertebrate community in order to contribute to the conservation of this species.