Ctenomys rionegrensis Langguth and Abella 1970

Ctenomys rionegrensis Langguth and Abella 1970, Comun. Zool. Mus. Hist. Nat. Montevideo, 10 (129): 13.

Type Locality: Uruguay, Dept. Rio Negro, Las Canas, 7 km S Fray Bentos.

Vernacular Names: Rio Negro Tuco-tuco.

Distribution: Entre Rios Prov. (Argentina) and Dept. Rio Negro (Uruguay).

Discussion: Included in minutus by Redford and Eisenberg (1992) but it is distinct based on cranial (Langguth and Abella, 1970), penial, and sperm morphology (Altuna and Lessa, 1985). The relationship with the four subspecies of minutus from Entre Rio Province named without describtion by Contreras and Contreras (1984) is unknown. Karyotype has 2n=48, 50, 52, or 56; FN=68-70, 72, 74, or 80 (Reig et al., 1992).