Oxychilus agostinhoi 

Scope: Global & Europe
Language: English

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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Mollusca Gastropoda Stylommatophora Oxychilidae

Scientific Name: Oxychilus agostinhoi Frias Martins, 1981
Taxonomic Source(s): Bank, R.A. 2017. Fauna Europeae Project: Checklist of the land and freshwater Gastropoda of Europe. Last update: February 18th, 2017. Fauna Europea Project: Hoogezand.

Assessment Information [top]

Red List Category & Criteria: Critically Endangered B1ab(i,ii,iii,v)+2ab(i,ii,iii,v) ver 3.1
Year Published: 2017
Date Assessed: 2016-11-28
Assessor(s): Cameron, R., de Frias Martins, A.M. & Teixeira, D.
Reviewer(s): Groh, K., Seddon, M.B., Neubert, E. & Allen, D.J.
This species is restricted to Santa Maria Island in the Azores Islands (Portugal), where it has a very small distribution, with a current extent of occurrence (EOO) and area of occupancy (AOO) of 4 km2. The species was previously known from three localities within a small area on Pico Alto and from Fontinhas, to the southeast of the mountain. There are no records after 2008 from three of the four known localities (Fontinhas, and the top and southern slope of Pico Alto), with the only known probably extant locality (shells only) on the northern slope of the mountain, with shells found in 2011. The species is threatened by habitat degradation and habitat destruction, as well as increasing frequency of droughts. The species is assessed as Critically Endangered (CR B1ab(i,ii,iii,v)+2ab(i,ii,iii,v)), based on the restricted range and a continuing decline in habitat area and quality.
Previously published Red List assessments:

Geographic Range [top]

Range Description:This species is endemic to Santa Maria Island in the Azores Archipelago (Martins et al. 1991, Cameron et al. 2012, A. Frias Martins pers. comm. 2016), where the species has a very small distribution. The species was formerly known from four localities on the island; the type locality at Fontinhas (Martins 1981), and from three localities on Pico Alto (one on the northern slope, one at the top of the mountain (collected in the 1990s), and one on the southern slope). The species was refound at the two localities on the southern and northern slopes of the mountain in 2008 (R. Cameron pers. comm. 2017), however in 2011, the species was only found at the single locality on the northern slope of Pico Alto (A. Frias Martins pers. comm. 2017). Hence the only recent records of the species (shells only) are from the northern slope of Pico Alto, with shells found in 2011 (A. Frias Martins pers. comm. 2017).
Countries occurrence:
Portugal (Azores)
Additional data:
Estimated area of occupancy (AOO) - km2:4Continuing decline in area of occupancy (AOO):Yes
Estimated extent of occurrence (EOO) - km2:4
Continuing decline in extent of occurrence (EOO):Yes
Number of Locations:1
Lower elevation limit (metres):300
Upper elevation limit (metres):600
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:The species has always been found in small numbers. When it was described in 1981, c.10 specimens were collected at the type locality and eight specimens (one dead, seven alive) were collected at the locality on the southern slope of Pico Alto (Martins 1981). The species was found again on Pico Alto (north and south slope localities) in small numbers in 2008 (Cameron et al. 2012). In 2011 the same sites were searched again and the species was not found at the site on the southern slope of Pico Alto (R. Cameron pers. comm. 2016), with shells found at the locality on the northern slope of Pico Alto in 2011 and 2017 (A. Frias Martins pers. comm. 2017). The species is probably now absent from the type locality and from the southern slope the top of Pico Alto.
Current Population Trend:Decreasing
Additional data:
Continuing decline of mature individuals:Yes
Extreme fluctuations:NoPopulation severely fragmented:No
All individuals in one subpopulation:Yes

Habitat and Ecology [top]

Habitat and Ecology:The species is mainly found in Laurisilva forests and Cryptomeria forests on upper slopes of Pico Alto. When first collected (Martins 1981), the species was also found on leaves of introduced Hedychium gardnerianum.
Continuing decline in area, extent and/or quality of habitat:Yes
Generation Length (years):1-2

Use and Trade [top]

Use and Trade: There is no known trade for this species.

Threats [top]

Major Threat(s): The species is threatened by habitat degradation and destruction, such as through the cultivation of Cryptomeria forests on upper slopes of Pico Alto, as well as the increasing frequency of droughts.

Conservation Actions [top]

Conservation Actions: There are no specific conservation actions in place for this species. The remaining probably extant locality on the northern slope of Pico Alto is within the protected area, Área Protegida para Gestão de Habitats ou Espécies do Pico Alto.

Citation: Cameron, R., de Frias Martins, A.M. & Teixeira, D. 2017. Oxychilus agostinhoi. The IUCN Red List of Threatened Species 2017: e.T15768A86033180. . Downloaded on 21 July 2018.
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