COMPOSITION AND CHARACTERISTICS OF A DIVERSE DIDELPHID COMMUNITY (MAMMALIA: DIDELPHIMORPHIA) IN SUB-TROPICAL SOUTH AMERICA.

Few studies have reported didelphid communities of ≥10 species, and all of these have been from within the tropics sensu stricto of South America. Herein a community of 12 species of didelphids is described from a sub-tropical site in south-central South America. The Reserva Natural del Bosque Mbaracayú, in northeastern Paraguay, lies at the western margin of the Interior Atlantic Forest and the southwestern limit of the Cerrado, two important South American ecoregions. The rich didelphid community in this area likely results from the mosaic of habitats encountered at the distributional limits of these two ecoregions. Within the context of this mosaic, the species' habitat associations and vertical occupancy are discussed, as well as the reproductive patterns and population abundance variation of the more commonly encountered species. Three Monodelphis species were found in sympatry, all strictly terrestrial, along with Cryptonanus chacoensis. Marmosa paraguayana shared all habitats with Gracilinanus agilis, and both of these species primarily were arboreal. Although this natural reserve has been more extensively sampled than any other area in Paraguay, numerous questions remain unanswered regarding this rich didelphid community.