Rhizosomichthys totae 

Scope: Global
Language: English

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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Actinopterygii Siluriformes Trichomycteridae

Scientific Name: Rhizosomichthys totae (Miles, 1942)
Common Name(s):
Spanish Pez Graso, Runcho
Pygidium totae Miles, 1942
Taxonomic Notes: No entry for this species in Eschmeyer 91998). The only entry for totae in Eschmeyer is Pygidium totae valid as Trichomycterus totae both from the same family, Trichomycteridae, as Rhizosomichthys. FishBase records R. totae as a synonym of T. totae based on Burgess (1989). Stiassny and Harrison (1999) indicate that this may just be a "fat form of Trichomycterus".

Assessment Information [top]

Red List Category & Criteria: Critically Endangered (Possibly Extinct) B1ab(iii,v) ver 3.1
Year Published: 2016
Date Assessed: 2014-10-10
Assessor(s): Mesa-Salazar, L. & Mojica, J.
Reviewer(s): Tognelli, M.
Facilitator/Compiler(s): Tognelli, M.
This species is listed as Critically Endangered (Possibly Extinct) because it is known only from Lago de Tota and has been collected in two instances, when it was described in 1942 and again in 1958. The species has not been collected since then, and it is suspected that the introduction in the lake of several fish species in 1944 has caused the decline of the population of this species. In addition, the lake is affected by pollution from agrochemicals from nearby agricultural activities. Surveys in the area in the 1990s failed to record the species in the lake.
Date last seen: 1958
Previously published Red List assessments:

Geographic Range [top]

Range Description:This species was known only from its type locality in Lake Tota, Boyacá, eastern Cordillera, Colombia, at an elevation of 3,060 meters (Miles 1942). The extent of occurrence is 70 km².
Countries occurrence:
Possibly extinct:
Additional data:
Number of Locations:1
Lower elevation limit (metres):3060
Upper elevation limit (metres):3060
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:It is only known from a few specimens used in the original description and one specimen collected in 1958. It has not been found since then (Mojica et al. 2012). Surveys in the area in the 1990's failed to record the species in the lake (J. Mojica pers. comm. 2014).
Current Population Trend:Unknown
Additional data:
Continuing decline of mature individuals:Yes

Habitat and Ecology [top]

Habitat and Ecology:

Almost no information is available on the biology and ecology of this species. The waters of Lake Tota are very transparent and not thermally stratified, and it is assumed that the deep layers where this species lives are well oxygenated.

Continuing decline in area, extent and/or quality of habitat:Yes

Use and Trade [top]

Use and Trade: The species is not utilized.

Threats [top]

Major Threat(s):

It is suspected that the introduction of exotic species is the main reason for this species' extinction, particularly Eremophilus mutisii, which is a close relative with similar morphology and is adapted to benthic conditions and, therefore, most likely to share the same ecological niche (Mojica et al. 2012). Other introduced taxa that are believed to compete with this species are Grundulus bogotensis, Carassius auratus and Oncorhynchus mykiss (Mojica et al. 2012). In addition, there is pollution by agrochemicals from nearby agricultural activities that is causing a continuing decline in the quality of the habitat.

Conservation Actions [top]

Conservation Actions: This species is listed as Extinct (EX) in the Red List of Freshwater Fishes of Colombia (Mojica et al. 2012). Surveys are needed during the appropriate season and in the appropriate habitats in order to determine if this species still exists.

Citation: Mesa-Salazar, L. & Mojica, J. 2016. Rhizosomichthys totae. The IUCN Red List of Threatened Species 2016: e.T19661A61472482. . Downloaded on 19 October 2017.
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