Geographic distribution of Rhyncholestes raphanurus Osgood, 1924 (Paucituberculata:Caenolestidae), an endemic marsupial of the Valdivian Temperate Rainforest

Abstract

The Chilean shrew opossum (Rhyncholestes raphanurus) is the southernmost representative of the family Caenolestidae (Marsupialia : Paucituberculata). The species lives in temperate forests of southern Chile and Argentina and is currently known from <25 localities, spanning a latitudinal and longitudinal range of 2°44′ (~320 km) and 2°20′ (~190 km), respectively. Species distribution was analysed in a historical, geographic and biogeographic context, with the use of maps at different scales (region, subregion, province, ecoregion, forest types), and two potential distribution models were generated with MaxEnt. The models show a few isolated areas of high prediction values (>50%) in coastal Chile and the Andes from 39°30′ to ~42°S, and most of Chiloé Island, plus a northern and southern expansion of medium to low (<50%) prediction values. The most important environmental variables identified from the models include precipitation and some temperature-related variables. The species occurrence lies within the Andean region, Subantarctic subregion, and Valdivian biogeographic province. At a smaller scale, most of the localities occur in eight of the 22 forest types described for the Valdivian ecoregion, implying narrow ecological requirements. Identification of critical areas through potential distribution modelling may have implications for species conservation and identification of biogeographic patterns.