Until recently Sminthopsis leucopus (Gray, 1842) was known from temperate southeastern Australia. The collection of two S. leucopus from montane tropical Queensland produces a 2100 km gap between tropical and temperate ranges. Minor cranial and dental differences between northern and southern specimens include smaller bullae, longer molar rows, bulkier premolars and widely-rooted upper incisors. The presence of S. leucopus in rainforest refugia may support the view that ancestral Sminthopsis was adapted to non-arid environments.