The purpose of this application, under Article 75.6 of the Code, is to conserve prevailing usage of the species group names tenuirostris Kuhl, 1820 and pastinator Gould, 1841, long employed for the southeastern and respetive south-western species of Australian long-billed corellas, genus Cacatua Vieillot, 1817. The only apparently traceable syntype of tenuirostris Kuhl has been found to be of the southwestern species; the resulting nomenclatural shift would destabilise established usage and confound past and future references to the name in literature. To conserve the long-accustomed use of tenuirostris Kuhl for the southeastern corella and to maintain pastinator Gould as the valid name for the southwestern long-billed corella, we propose that the only known syntype of tenuirostris Kuhl be set aside and replaced with a neotype of the southeastern species.