The Southernmost Known Population of the Monito Del Monte, Dromiciops gliroides

The monito del monte (genus Dromiciops) is a small arboreal marsupial endemic to the temperate rainforests of southern South America, and the sole extant representative of the order Microbiotheria. This lineage, considered a sister group of Australian marsupials, is of great evolutionary, ecological, and conservation significance. Until recently, the southern distribution limit of D. gliroides was thought to extend as far as Futaleufú in Chile (~43° S). Here, we document a new population approximately 100 km southwards, near Río Figueroa in central Patagonia (44° S). A specimen collected at Fundo La Bella Patagonia was genetically assigned to the southern clade of D. gliroides through mitochondrial (Cytb) and nuclear (IRBP) markers, clustering with populations from Chiloé Island and the southern Andes. This discovery extends the known range of the species into an area where Nothofagus-Chusquea forest persists, highlighting the resilience of this relict lineage under increasingly colder and seasonal conditions. The discovery of this new record strongly suggests the existence of dense, previously undocumented populations in the Aysén region and potentially in areas further south. Conservation efforts should, therefore, prioritize these newly documented populations, which may act as critical refugia and genetic reservoirs for Microbiotheria in the face of ongoing climate and land-use change.