Superregnum: Eukaryota
Cladus: Unikonta
Cladus: Opisthokonta
Cladus: Holozoa
Regnum: Animalia
Subregnum: Eumetazoa
Cladus: Bilateria
Cladus: Nephrozoa
Superphylum: Deuterostomia
Phylum: Chordata
Subphylum: Vertebrata
Infraphylum: Gnathostomata
Megaclassis: Osteichthyes
Cladus: Sarcopterygii
Cladus: Rhipidistia
Cladus: Tetrapodomorpha
Cladus: Eotetrapodiformes
Cladus: Elpistostegalia
Superclassis: Tetrapoda
Cladus: Reptiliomorpha
Cladus: Amniota
Cladus: Synapsida
Cladus: Eupelycosauria
Cladus: Sphenacodontia
Cladus: Sphenacodontoidea
Cladus: Therapsida
Cladus: Theriodontia
Cladus: Cynodontia
Cladus: Eucynodontia
Cladus: Probainognathia
Cladus: Prozostrodontia
Cladus: Mammaliaformes
Classis: Mammalia
Subclassis: Trechnotheria
Infraclassis: Zatheria
Supercohors: Theria
Cohors: Eutheria
Infraclassis: Placentalia
Cladus: Boreoeutheria
Superordo: Euarchontoglires
Ordo: Rodentiaa
Subordo: Myomorpha
Superfamilia: Muroidea
Familia: Muridae
Subfamilia: Murinae
Tribus: Praomyini
Genus: Nilopegamys
Species: Nilopegamys plumbeus
Name
Nilopegamys plumbeus Osgood, 1928: 185
Holotype: FMNH 28633, adult ♂, skin and skull, collected on 20 March 1927.
Type locality: “small stream tributary of the Little Abbai, between Sakalla and Njabarra [= Enjibara, Injibarra], Gojam, Abyssinia [=Ethiopia]. Altitude 8500 ft [=2800 m]”.
References
Primary references
Osgood, W.H. 1928. A new genus of aquatic rodents from Abyssinia. Field Museum of Natural History, Zoological Series 12(15): 185–189. BHL Reference page.
Links
Dando, T. 2021. IUCN: Nilopegamys plumbeus (Critically Endangered). The IUCN Red List of Threatened Species 2021: e.T40766A22431448. DOI: 10.2305/IUCN.UK.2021-3.RLTS.T40766A22431448.en. Accessed on 17 May 2024.
Vernacular names
English: Ethiopian Amphibious Rat
The Ethiopian amphibious rat, also known as the Ethiopian water mouse (Nilopegamys plumbeus), is an insectivorous and semiaquatic species of rodent in the monotypic genus Nilopegamys of the family Muridae. There has only been one known specimen. It was found along the Lesser Abay River near its source at an altitude of 2600 m in the highlands of northwestern Ethiopia in 1928.[2] N. plumbeus is considered to be the most aquatically adapted African murid; its unusually large brain is thought to be one consequence of this lifestyle.[3] The species is considered to be critically endangered or possibly extinct, since its habitat has been severely damaged by overgrazing and monoculture.[4]
Distribution and discovery
In late March 1928, the Ethiopian amphibious rat was cataloged for the first time.[5] The specimen was discovered in a trap set by Wilfred H. Osgood, and was unlike any African rat he had seen before. The rat showed multiple adaptations to aquatic life which is uncommon for rats in Africa. Aquatic rats have been observed in South America but never before in east Africa.[5]
The Ethiopian amphibious rat has been spotted very few times in the wild. It has been sighted in the Ethiopian highlands in their wetland areas. The single found specimen was located near the Lesser Abay River in central Ethiopia.[3] This rat is listed as critically endangered but many researchers studying the rodent fear it is already extinct due to two failed attempts to locate and track the rat.[2]
Anatomy
Nilopegamuys plumbeus is specifically adapted to live near or in close contact with water. There are other rodents adapted to live in wetlands such as marsh rice rat or the European water vole. Out of all other African aquatic rodents however, the Ethiopian amphibious rat has the most extreme adaptations to its environment.[6] They have a pair of adapted “waders” on their feet recognizable as webbing.[6] Since N. plumbeus is so specifically adapted to its environment it makes living elsewhere very difficult. This is why scientists think that with the degradation of its habitat, N. plumbeus is now likely extinct.[4]
The rat belongs to the family Muridae and has the largest cranial capacity of any African muroid ever sampled.[3] They also have very large brains compared to their body size and given the average brain size of aquatic rodents.[3]
Status
Threats
The main reason for the population decline of the Ethiopian amphibious rat is habitat loss.[2] Although not much research has been done on the preexisting population size of this rat species, it can be said the population has declined drastically with the destruction of its habitat. The leading cause for the destruction of Ethiopian highland, wetlands is loss to livestock grazing.[4] Their habitat is almost completely destroyed due to this clearing for grazing and there is little being done to protect it. Ranching has also contributed to this habitat loss but not to the same scale.[4]
Conservation & further knowledge
At the time there is not much in place in terms of conservation for the Ethiopian amphibious rat.[2] They are considered critically endangered by the IUCN red list and even possibly extinct.[4] There is also very little research that has been done on this species. Currently, East African highland small mammals are being studied by Julian Kerbis Peterhans at the Field Museum in Chicago Illinois, USA.[2] Almost all that is known about this species is taken from a single study that was conducted in the 1920s. More research about this species, its habits, and its environment are needed.[7]
References
Kerbis Peterhans, J.; Lavrenchenko, L. (2008). "Nilopegamys plumbeus". IUCN Red List of Threatened Species. 2008: e.T40766A194057314. doi:10.2305/IUCN.UK.2008.RLTS.T40766A194057314.en. Retrieved 14 November 2021.
"Ethiopian water mouse | SMSG - Small Mammal Specialist Group". www.small-mammals.org. Retrieved 2019-04-16.
"Mammal Species of the World - Browse: plumbeus". www.departments.bucknell.edu. Retrieved 2019-04-16.
"The IUCN Red List of Threatened Species". IUCN Red List of Threatened Species. Retrieved 2019-04-16.
"Scientific Illustration". Scientific Illustration. Retrieved 2019-04-18.
Patterson, Bruce D.; Peterhans, Julian C. Kerbis (1995-03-01). "The Ethiopian water mouse Nilopegamys Osgood, with comments on semi-aquatic adaptations in African Muridae". Zoological Journal of the Linnean Society. 113 (3): 329–349. doi:10.1111/j.1096-3642.1995.tb00937.x. ISSN 0024-4082.
"Ethiopian water mouse | SMSG - Small Mammal Specialist Group". 2020-08-13. Archived from the original on 2020-08-13. Retrieved 2023-11-22.
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