IUCN SSC Mid-Atlantic Island Invertebrates Specialist Group

Species

BackChrysotus elongatus Parent, 1934

Chrysotus elongatus Parent, 1934

  • Kingdom: Animalia
  • Phylum: Arthropoda
  • Class: Insecta
  • Order: Diptera
  • Family: Dolichopodidae
LC Least Concern
IUCN Red List Status:

Countries of Occurrence:
Portugal - Azores

Archipelago(s):
Azores

Reviewer/s:
Danielczak, A.

Contributor/s:

Facilitators / Compilers/s:


Assessment Rationale:

Chrysotus elongatus is an endemic species of the Azores (Portugal), being present on Corvo, Flores, Faial, Pico, S. Jorge, Terceira and S. Miguel islands. This species is apparently common and widespread through a wide variety of natural and disturbed habitats in the aforementioned islands (Frey 1945). From the historical data, this species could have a relatively large Extent of Occurrence (26,260 km2) but a small Area of Occupancy (380 km2). It is possible that this species has declined in the past as a result of human activity, but 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. Conservation of native forests and vegetation, native wet and boggy areas and natural streams and other water bodies could potentially aid this species' conservation. Even though there is a paucity of recent data regarding this species' population, distribution, threats and ecology, this species is unlikely to warrant listing as threatened under any criterion, and so it is listed as Least Concern.

Geographic Range:

Chrysotus elongatus is an Azorean-endemic species that was described from the islands of Corvo, Flores, Faial, Pico, S. Jorge, Terceira and S. Miguel (Azores, Portugal) (Borges et al. 2010), known from a wide variety of habitats. Based on the historical data (Frey 1945), the Extent of Occurrence (EOO) could be ca. 26,260 km² and the Area of Occupancy (AOO) could be ca. 380 km². However, there is no recent information regarding the distribution of this species.

Regions:
Portugal - Azores
Extent of Occurrence (EOO):
26,260 (km2)
Area of Occupancy (AOO):
380 (km2)
Elevation Lower Limit:
(m)
Elevation Upper Limit:
(m)
Biogeographic Realms:
Palearctic
Presence:
Extant
Origin:
Endemic Azores
Seasonality:
Resident

Population:

No current population size estimates exist. Nevertheless, from the samples collected in 1938 this species seemed to be fairly common and widespread through the Azores archipelago. Current Population Trend: Unknown. 

Habitat and Ecology

The ecology and traits of this species are unknown. Adults and most larvae of other species of Dolichopodidae are predators, feeding on other arthropods, with the adults of some species being notable predators of Culicidae (McAlpine et al. 1987). The larvae occupy a wide range of habitats, living generally in moist environments such as soil, moist sand, or rotting organic matter. The larvae pupate in cocoons made of cemented soil particles. Dolichopodidae in general inhabit lightly shaded areas near swamps and streams, or in meadows and woodlands (McAlpine et al. 1987). Other species of the genus Chrysotus are generally heliophilous, being found mainly on the foliage of low herbs, while a number of species seem to prefer wet, sandy banks of ponds and rivers. Chrysotus elongatus has been found in a wide variety of habitats, mainly in native, deciduous and production forests (Cryptomeria japonica), heathland, in coastal areas, rocky altitude areas, near lakes and streams, in moorlands and in other wet and moist areas. Systems: Terrestrial.

Major Threat(s):

A lack of information regarding the present status of this species precludes an assessment of potential threats. Nevertheless, the ecology of other members of the Dolichopodidae family suggests that this species might be affected by future habitat declines as a consequence of climate change (Ferreira et al. 2016) and increased droughts. Past human disturbance and land use changes might have also affected this species. 

Conservation Actions

This species is not protected by regional law. The present situation of this species needs to be assessed, and further research is needed into its population, distribution, threats, ecology and life history. From what is known of its habitat preferences, conservation of native forests, native wet and boggy areas, natural streams and other water bodies could potentially aid this species' conservation. Historically at least, this species was present in areas that are currently included in the Natural Parks of Flores, Faial, Pico, Terceira and S. Miguel.