The Rio Negro tuco-tuco (''Ctenomys rionegrensis'') is a species of

rodent Rodents (from Latin , 'to gnaw') are mammals of the order Rodentia (), which are characterized by a single pair of continuously growing incisors in each of the upper and lower jaws. About 40% of all mammal species are rodents. They are na ...

in the family

Ctenomyidae A tuco-tuco is a neotropical rodent in the family Ctenomyidae.Parada, A., G. D’Elia, C.J. Bidau, and E.P. Lessa. 2011. Species Groups and the Evolutionary Diversification of Tuco-Tucos, genus ''Ctenomys'' (Rodentia: Ctenomyidae). ''Journal of M ...

. It is found in a small fragmented range in

Entre Ríos Province Entre Ríos (, "Between Rivers") is a central province of Argentina, located in the Mesopotamia region. It borders the provinces of Buenos Aires (south), Corrientes (north) and Santa Fe (west), and Uruguay in the east. Its capital is Paraná ( ...

in northeastern

Argentina Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the second-largest country in South America after Brazil, th ...

and in the

Río Negro Department Río Negro Department ( es, Departamento de Río Negro, ) is a department of the northwestern region of Uruguay. It has an area of and a population of 54,765. Its capital is Fray Bentos. It borders Paysandú Department to the north, Tacuarembó D ...

of western

Uruguay Uruguay (; ), officially the Oriental Republic of Uruguay ( es, República Oriental del Uruguay), is a country in South America. It shares borders with Argentina to its west and southwest and Brazil to its north and northeast; while bordering ...

. It is restricted to sand dunes, and is threatened by the conversion of this habitat to forestry plantations.

References

Mammals of Argentina Mammals of Uruguay Mammals described in 1970 Tuco-tucos {{rodent-stub