Thorius narismagnus 

Scope: Global
Language: English

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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Amphibia Caudata Plethodontidae

Scientific Name: Thorius narismagnus Shannon & Werler, 1955
Common Name(s):
English San Martin Pigmy Salamander
Taxonomic Source(s): Frost, D.R. 2015. Amphibian Species of the World: an Online Reference. Version 6.0. New York, USA. Available at:

Assessment Information [top]

Red List Category & Criteria: Critically Endangered B1ab(iii,v) ver 3.1
Year Published: 2016
Date Assessed: 2014-09-10
Assessor(s): IUCN SSC Amphibian Specialist Group
Reviewer(s): Lamoreux, J.
Contributor(s): Wake, D., Pineda, E., Parra-Olea, G., Hanken, J. & García París, M.
Facilitator/Compiler(s): Hobin, L. & Arias Caballero, P.
Listed as Critically Endangered because its extent of occurrence (EOO) is 17 km2, it occurs in one threat-defined location, and there is continuing decline in the extent and quality of its habitat and in the number of mature individuals, in southern Veracruz, Mexico.
Previously published Red List assessments:

Geographic Range [top]

Range Description:This species is known only with certainty from one threat-defined location of Volcán San Martín in the Sierra de Los Tuxtlas, southern Veracruz, Mexico, between 500-1,200 m asl. It may be present on the adjacent Santa Marta, however this requires confirmation. Its extent of occurrence (EOO) and area of occupancy (AOO) is 19 km2.
Countries occurrence:
Mexico (Veracruz)
Additional data:
Estimated area of occupancy (AOO) - km2:19.09
Number of Locations:1
Lower elevation limit (metres):500
Upper elevation limit (metres):1200
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:This species appears to have undergone a population collapse, possibly in the late 1970s, although its cause is not clear. This species was never common, but it was found consistently (and often in large numbers) from the 1950s to the mid-1970s. From 1976 it was not found for 36 years, until 2012 when Eduardo Pineda and his group from INECOL found three specimens at Ejido Ruiz Cortines Volcán San Martín, Los Tuxtlas. Due to ongoing declines in the extent and quality of habitat, the population is suspected to be decreasing.
Current Population Trend:Decreasing
Additional data:
Continuing decline of mature individuals:Yes
Population severely fragmented:Yes

Habitat and Ecology [top]

Habitat and Ecology:It is a terrestrial species that inhabits lowland and intermediate tropical forest, being found under rotten logs and among leaf-litter especially under fallen bromeliads (Hanken and Wake 1998). It presumably reproduces by direct 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): Serious habitat loss is taking place in the range of this species due to subsistence agriculture, logging, and human settlement. However, this might not be sufficient to explain its apparent disappearance. The timing of the drop off in numbers is broadly consistent with documented declines in other salamander species in mountain ranges to the west (Rovito et al. 2009). As with those species, it is possible that this species was negatively affected by the arrival of chytridiomycosis (Cheng et al. 2011), although there is as yet no evidence to support such a conclusion.

Conservation Actions [top]

Conservation Actions: Conservation Actions
It occurs in San Martín National Park, and may be present in Santa Marta National Park. 

Conservation Needed
Continued protection and maintenance of the species' remaining habitat is required.

Research Needed
Research is needed into the causes of its dramatic decline.

Citation: IUCN SSC Amphibian Specialist Group. 2016. Thorius narismagnus. The IUCN Red List of Threatened Species 2016: e.T59420A53986703. . Downloaded on 22 April 2018.
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