Sabulopteryx botanica Hoare & Patrick, sp. nov. (Lepidoptera, Gracillariidae, Gracillariinae) is described as a new species from New Zealand. It is regarded as endemic, and represents the first record of its genus from the southern hemisphere. Though diverging in some morphological features from previously described species, it is placed in genus Sabulopteryx Triberti, based on wing venation, abdominal characters, male and female genitalia and hostplant choice; this placement is supported by phylogenetic analysis based on the COI mitochondrial gene. The life history is described: the larva is an underside leaf-miner on the endemic divaricating shrub Teucrium parvifolium (Lamiaceae), and exits the mine to pupate in a cocoon in a folded leaf of the host plant. The remarkable history of the discovery and rediscovery of this moth is discussed: for many years it was only known from a single sap-feeding larva found in a leaf-mine in a pressed herbarium specimen of the host. The adult was discovered by BHP in Christchurch Botanic Gardens in 2013. Most distribution records of the moth come from a recent search for mines and cocoons on herbarium specimens of T. parvifolium. Sabulopteryx botanica has high conservation status, and is regarded as 'Nationally Vulnerable' according to the New Zealand Department of Conservation threat classification system, based on the rarity and declining status of its host plant. However, the presence of apparently thriving populations of S. botanica on cultivated plants of T. parvifolium, especially at the type locality, Christchurch Botanic Gardens, suggests that encouraging cultivation of the plant could greatly improve the conservation status of the moth. A revised checklist of New Zealand Gracillariidae is presented, assigning all species to the currently recognised subfamilies. The Australian Macarostola ida (Meyrick, 1880) is newly recorded from New Zealand (Auckland), where it is established on Eucalyptus.