Nilopegamys plumbeus Osgood, 1928:185

Ethiopian amphibious rat, Ethiopian water mouse



Taxonomy & Nomenclature

Synonym/s: Colomys goslingi plumbeus Osgood, 1928:185


Conservation Status


Last (and only) record: 1927; 1928 (Fisher & Blomberg, 2012; Lee et al., 2017; Martin et al., 2023)

IUCN RedList status: Critically Endangered (Possibly Extinct)


The Ethiopian amphibious rat is only known from the holotype. Several attempts have been made to collect this species again but without any success (Kerbis Peterhans & Lavrenchenko, 2008).



Gojjam, Ethiopia (north-western)


Biology & Ecology










Original scientific description:

Osgood, W. H. (1928). [description of Nilopegamys plumbeus]. Field Mus. Nat. Hist., Zool. Ser. 12: 185.


Other references:

Allen, G. M. (1939). A checklist of African mammals. Bulletin of the Museum of Comparative Zoology at Harvard College 83: 1-763.

Dando, T. 2021. Nilopegamys plumbeus. The IUCN Red List of Threatened Species 2021: e.T40766A22431448. Accessed on 09 July 2022.

Dieterlen, F. 1983. Zur Systematik, Verbreitung und Ökologie von Colomys goslingi Thomas & Wroughton, 1907 (Muridae; Rodentia). Bonner Zoologische Beiträge, 34:73-106.

Ellerman, J. R. 1941. The families and genera of living rodents. Vol. II. Family Muridae. British Museum (Natural History), London, 690 pp.

Fisher, Diana O. and Blomberg, Simon P. (2012). Inferring Extinction of Mammals from Sighting Records, Threats, and Biological Traits. Conservation Biology 26(1): 57-67.

Giarla, Thomas C. et al. (2021). Integrative taxonomy and phylogeography of Colomys and Nilopegamys (Rodentia: Murinae), semi-aquatic mice of Africa, with descriptions of two new species. Zoological Journal of the Linnean Society 192(1): 206-235. [Abstract]

Hayman, R. W. (1966). On the affinities of Nilopegamys plumbeus Osgood. Annales Musée Royal de l'Afrique Centrale, Tervuren, Belgique, ser. 8 (Sciences Zoologiques) 144: 29-38. [Abstract]

Holmes, Branden. (2021). What's Lost and What Remains: The Sixth Extinction in 100 Accounts (eBook). Self published.

Kostin, Danila S. et al. (2020). Rodents of Choke Mountain and surrounding areas (Ethiopia): the Blue Nile gorge as a strong biogeographic barrier. J. of Vertebrate Biology 69(2): 1-12.

Kerbis Peterhans, J. and Lavrenchenko, L. (2008). Nilopegamys plumbeus. In: IUCN 2011. IUCN Red List of Threatened Species. Version 2011.1. ( Downloaded on 17 July 2011.

Kerbis Peterhans, J. C. and Patterson, B. D. (1995). The Ethiopian water mouse Nilopegamys Osgood, with comments on semi-aquatic adaptations in African Muridae. Zoological Journal of the Linnean Society 113: 329-349.

Lee, T. E., Fisher, D. O., Blomberg, S. P. and Wintle, B. A. (2017). Extinct or still out there? Disentangling influences on extinction and rediscovery helps to clarify the fate of species on the edge. Global Change Biology 23(2): 621-634.

Martin, Thomas E., Bennett, Gareth C., Fairbairn, Andrew J. and Mooers, A. Ø. (2023). ‘Lost’ taxa and their conservation implications. Animal Conservation 26(1): 14-24. [Appendix S2 (1617 taxa not seen >10 years); Appendix S3 (562 taxa not seen >50 years)]

Mohamed bin Zayed Species Conservation Fund. (2015). Annual report 2015. Available from: [Accessed 14 January 2017]

Musser, G.G. and Carleton, M.D. 2005. Superfamily Muroidea. In: D.E. Wilson and D.A. Reeder (eds), Mammal Species of the World: a geographic and taxonomic reference, pp. 894-1531. The John Hopkins University Press, Baltimore, USA.

Nowak, R. M. 1999. Walker's Mammals of the World. The Johns Hopkins University Press, Baltimore, USA and London, UK.

Vargas, Pablo. (2023). Exploring ‘endangered living fossils’ (ELFs) among monotypic genera of plants and animals of the world. Frontiers in Ecology and Evolution 11: 1100503.

Yalden, D.W., Largen, M.J., Kock, D. and Hillman, J.C. 1996. Catalogue of the Mammals of Ethiopia and Eritrea. 7. Revised checklist, zoogeography and conservation. Tropical Zoology 9(1): 73-164.


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