New contributions to the knowledge of the marsupials (Didelphimorphia: Didelphidae) of southern Santa Fe province, Argentina

In Argentina, the increasing demand of land for agricultural production, together with the effects of population growth, have been important factors in the alteration of the environments of the Pampas region. Marsupials represent a group of mammals with a long evolutionary history in this territory. Few species have been historically recorded in the province of Santa Fe, and most of these records come from the north and center of the province. In the present contribution we analyze the distribution patterns and habitat preference of didelphids present in the south of Santa Fe province. The study area corresponds to the Carcarañá river basin and the methodology used was: standardized line transects in search of signs of activity, camera traps and analysis of Tyto furcata pellets. In order to establish associations between the records of presence and the environmental variables studied (distance to roads and wire fences, ground cover, etc.), a geographic information system was generated. As a result, 3 species were recorded: Didelphis albiventris, Lutreolina crassicaudata and Monodelphis dimidiata. The principal component analysis showed that distance to urban centers, type of cover and vegetation heterogeneity are the variables that best explain the presence records of the species under study. Although the number of specimens is low, the results are relevant because these species have been little studied in Argentina and there are few or no records in the area. The transformation and degradation of the natural habitat due to the advance of the agricultural frontier is the main threat to these species.