The nomenclature, taxonomy and conservation status of Ogyris waterhouseri (Bethune-Baker, 1905) stat. nov. (Lepidoptera: Lycaenidae), a threatened butterfly from southern Australia

The nomenclature and taxonomic status of Ogyris waterhouseri is revised and considered to be specifically distinct from Ogyris idmo (Hewitson 1862) based on fundamental differences in juvenile and adult morphology. For the past 94 years, O. waterhouseri has been treated either as a geographical subspecies or as synonym of O. idmo, and for the last 36 years it has been known under the name O. idmo halmaturia (Tepper 1890), which we show to be a junior synonym of O. otanes (C. & R. Felder 1865). Assessment of the conservation status of O. waterhouseri indicates that the butterfly warrants listing as Endangered nationally according to IUCN criteria. The species is restricted to habitats comprising heathland, mallee-heathland or mallee low open-woodland with a heath understorey on sand where colonies of the associated ant, Camponotus terebrans Lowne, 1865, occur abundantly. Ogyris waterhouseri formerly had a wide range in the coastal and semi-arid areas of southern Australia (western and south-western Victoria, southern South Australia); however, its geographic range is estimated to have contracted by about 88-98%, primarily due to habitat loss. Currently, the species is known from only two fragmented populations comprising a total of six extant sites. The common name Eastern Bronze Azure is proposed for O. waterhouseri.