The Dotted-Line Robust Slider, Lerista lineopunctulata (Duméril & Bibron, 1839), is widely distributed along the western coast of Western Australia. An investigation of diversity within this taxon showed a clear split between northern and southern populations in the vicinity of Jurien. Accordingly, Lerista lineopunctulata is restricted to the southern population while the northern is recognised as Lerista miopus (Günther, 1867). Both taxa are redescribed and diagnosed and a neotype for L. miopus is designated.

Global biodiversity loss is a profound consequence of human activity. Disturbingly, biodiversity loss is greater than realized because of the unknown number of undocumented species. Conservation fundamentally relies on taxonomic recognition of species, but only a fraction of biodiversity is described. Here, we provide a new quantitative approach for prioritizing rigorous taxonomic research for conservation. We implement this approach in a highly diverse vertebrate group-Australian lizards and snakes. Of 870 species assessed, we identified 282 (32.4%) with taxonomic uncertainty, of which 17.6% likely comprise undescribed species of conservation concern. We identify 24 species in need of immediate taxonomic attention to facilitate conservation. Using a broadly applicable return-on-investment framework, we demonstrate the importance of prioritizing the fundamental work of identifying species before they are lost.