Comentarios sobre el estatus de Calomys callosus (Rengger) y nuevos datos sobre la distribución de micromamíferos en el noroeste de la provincia de Corrientes (Argentina)

Abstract

From cytogenetic and morphologic data, correspondence between Calomys callosus and C. callidus is discussed. The karyotypes described here for specimens of C. callosus from the province of Corrientes are almost identical with those described by other authors for specimens from the province of Entre Ríos (ascribed to C. callidus). Known data restrict the geographic range of Calomys callosus to the neighbourhood of the flood valley of the Paraguay River and the Argentine Mesopotamia. Furthermore, new distributional records of 16 species of small mammals (Marsupialia, Chiroptera, Rodentia) are presented from two localities in the northwest of the province of Corrientes: El Sombrero (27º 70’S - 58º 58’ W), department of Empedrado, and El Pontón (27º 56’S - 58º 45’ W), department of San Luis del Palmar. At both localities bone remains, mainly hemimandibles and cranial fragments, were recovered from Barn Owl pellets. The samples are largely dominated by Holochilus sp., with low frequencies of Akodon cf. A. azarae, Akodon montensis, Calomys callosus, Gracilinanus agilis, Necromys temchuki, Oligoryzomys sp. cf. O. flavescens - O. microtis, Oligoryzomys nigripes, Scapteromys aquaticus and Oxymycterus rufus