Aegialomys galapagoensis 

Scope: Global
Language: English

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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Mammalia Rodentia Cricetidae

Scientific Name: Aegialomys galapagoensis (Waterhouse, 1839)
Common Name(s):
English Galapagos Rice Rat, Galapagos Oryzomys
Oryzomys bauri Allen, 1892
Oryzomys galapagoensis (Waterhouse, 1839)
Taxonomic Notes: Oryzomys is a generic synonym (Weksler et al. 2006). Musser and Carleton (1993) note that this taxon has two subspecies: Aegialomys galapagoensis bauri which occurs on Santa Fe Island (Barrington) and A. g. galapagoensis which occurred on San Cristobal Island (Chatham) and which is now said to be extinct (Dowler et al. 2000). Patton and Hafner (1983) demonstrated that the two populations are conspecific.

Assessment Information [top]

Red List Category & Criteria: Vulnerable D2 ver 3.1
Year Published: 2018
Date Assessed: 2016-09-12
Assessor(s): Weksler, M.
Reviewer(s): Amori, G.
Contributor(s): Tirira, D.G. & Boada, C.
This species is assessed as Vulnerable under criterion D2 because it has a very restricted population with only one remaining location, which is potentially threatened by the possibility of exotic species being introduced to the island. Currently the species is not in decline, however, the only other population was extirpated from a neighbouring island due to exotic species introductions. Thus this species is highly susceptible to rapid extinction in future should invasive species be introduced to its remaining distribution area.
Previously published Red List assessments:

Geographic Range [top]

Range Description:This species is endemic to the Galápagos Islands. It occurs only on Sante Fe (Barrington) Island, and previously occurred on San Cristobal (Chatham) Island (Percequillo 2015). Aegialomys galapagoensis was first described from specimens collected from Santa Cruz Island by Charles Darwin in 1835. Later studies suggested that A. bauri from Santa Fe, and A. galapagoensis were so similar that they may be considered conspecific (Patton and Hafner 1983).
Countries occurrence:
Ecuador (Galápagos)
Additional data:
Continuing decline in extent of occurrence (EOO):Unknown
Number of Locations:1
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:This species includes two populations: Aegialomys galapagoensis galapagoensis occured on San Cristobal Island, but this population is now extinct (Dowler et al. 2000, Tirira 2001); and A. g. bauri occurs in Santa Fe Island, where it is common (Dowler et al. 2000, Tirira 2001).
Current Population Trend:Unknown
Additional data:
Population severely fragmented:No

Habitat and Ecology [top]

Habitat and Ecology:Its ecology and natural history are poorly known. It is terrestrial and solitary.

Threats [top]

Major Threat(s): The history of the decline and likely extinction of the population on San Cristobal Island, with the increase and spread of introduced species has been well documented (Dowler et al. 2000). The introduction of exotic rats (Rattus rattus) or mice (Mus musculus) to Santa Fe Island remains the main threat to the species. History suggests that the species could easily become extinct due to invasive predators and competitor species and this should be a conservation priority.

Conservation Actions [top]

Conservation Actions: Control exotic species and access to the island, and enact a program to prevent the introduction of common rats.

Citation: Weksler, M. 2018. Aegialomys galapagoensis. The IUCN Red List of Threatened Species 2018: e.T15595A22336232. . Downloaded on 24 September 2018.
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