Paraguay Oriental (Mammalia, Rodentia, Ctenomyidae)

Abstract

Ctenomys paraguayensis, a new species of fossorial rodent from Eastern Paraguay (Mammalia, Rodentia, Ctenomyidae). Ctenomys paraguayensis, a new species of the so called angujá-tutú or tuco-tuco is described from a small group of specimens secured at Coraté-i, near Ayolas, department of Misiones, Paraguay. The new species has cytogenetic and morphological distinctiveness within the whole known species of the genus. The karyotype is 2n=52, showing some affinities with the species ranging in the north of the Province of Corrientes, Argentina (from the Ctenomys perrensi-roigi and the dorbignyi-pearsoni complexes), but is not closely related with that of the neighbouring Ctenomys pilarensis Contreras, 1993 from the departament of Ñeembucú, Paraguay. Comparative analysis of morphometric, osteological and general somatic characteristics indicated a clear differentiation of the new species with Ctenomys pilarensis and a non close affinty with the north-mesopitamic species of the genus. Perhaps historical considerations justify the assumption that Ctenomys paraguayensis may be the representative of Ctenomys tucotuco Brants, 1827, a bibliographically based species, representing the Azara’s (1802) "tucu-tuco" from Paraguay, but definitive evidence of that statement is lacking. Because of the great environmental change due to the Yacyretá Dam, Ctenomys paraguayensis is apparently very prone to extinction if not yet vanished in its very restricted geographic range, endemic of Eastern Paraguay.