Gephyromantis silvanus 

Scope: Global
Language: English

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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Amphibia Anura Mantellidae

Scientific Name: Gephyromantis silvanus (Vences, Glaw & Andreone, 1997)
Mantidactylus silvanus Vences, Glaw & Andreone, 1997
Taxonomic Source(s): Frost, D.R. 2013. Amphibian Species of the World: an Online Reference. Version 5.6 (9 January 2013). Electronic Database. American Museum of Natural History, New York, USA. Available at:

Assessment Information [top]

Red List Category & Criteria: Vulnerable B1ab(iii) ver 3.1
Year Published: 2016
Date Assessed: 2015-10-16
Assessor(s): IUCN SSC Amphibian Specialist Group
Reviewer(s): Stuart, S.N.
Contributor(s): Andreone, F., Scherz, D. & Vences, M.
Facilitator/Compiler(s): Sharp, D., Luedtke, J. & Hobin, L.
Listed Vulnerable because the extent of occurrence is 5,722 km2, it occurs in fewer than ten threat-defined locations, and there are ongoing declines in the extent and quality of its habitat.
Previously published Red List assessments:

Geographic Range [top]

Range Description:This species was previously known only from the island of Nosy Mangabe and the nearby mainland along the coast of the Antongila Bay, from 0-400m asl. It has now also been found to occur at Ambodiriana (around 150 km south of Maroantsetra) (Gehring et al., 2010). It is likely to occur at several sites between Ambodiriana and Maroansetra and may also occur on the Masoala Peninsula. The extent of occurrence is 5,722 km2.
Countries occurrence:
Additional data:
Number of Locations:1-9
Upper elevation limit (metres):400
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:It is a rare species and, due to ongoing declines in the extent and quality of habitat, the population is suspected to be decreasing.
Current Population Trend:Decreasing
Additional data:
Population severely fragmented:No

Habitat and Ecology [top]

Habitat and Ecology:It lives on low vegetation near streams and brooks, and among boulders and in caves in pristine rainforest; it cannot survive in altered habitats. Calling males have been heard from large cavities between boulders during the day and specimens have been found active near these cavities at night (Glaw and Vences, 2007). The breeding biology is unknown - it could reproduce by either direct or larval development.
Continuing decline in area, extent and/or quality of habitat:Yes
Movement patterns:Not a Migrant

Use and Trade [top]

Use and Trade: There are no records of this species being utilized.

Threats [top]

Major Threat(s): The major threat is habitat loss due to subsistence agriculture, timber extraction, charcoal manufacture, livestock grazing, and expanding human settlements.

Species in this genus have tested positive for Batrachochytrium dendrobatidis (Bd), however currently there have been no negative effects observed within amphibian populations in Madagascar suggesting the Bd strain has a low virulence level (Bletz et al., 2015).

Conservation Actions [top]

Conservation Actions: Conservation Actions
It occurs in the Réserve Spéciale de Nosy Mangabe. Although not yet confirmed from Parc National de Masoala it is likely to occur there as well.

Conservation Needed
Improved protection and management of forests throughout the region is required, including within the boundaries of protected areas.

Research Needed
Further research is required to clarify the species' natural history, distribution, population size and trends, and is essential to fully understand the distribution, origin, type and virulence of Bd lineages found in Madagascar (Bletz et al., 2015).

Citation: IUCN SSC Amphibian Specialist Group. 2016. Gephyromantis silvanus. The IUCN Red List of Threatened Species 2016: e.T57522A84176478. . Downloaded on 25 September 2018.
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