Kakanuiella (gen. nov.) and Thecidellina:: Cenozoic and Recent thecideide brachiopods from New Zealand

Small cemented thecideide brachiopods occur sporadically in Cenozoic strata in New Zealand, Australia, and elsewhere in the south-west Pacific, and living species assigned to the genus Thecidellina are widespread in the subtropical and tropical regions of the Pacific Ocean from northern New Zealand to Japan. We propose a new generic name, Kakanuiella, for the species Thecidellina hedleyi which occurs in limestones and tuffs of Eocene and Oligocene age in New Zealand, including the Chatham Islands. Pliocene specimens of Thecidellina from the Chatham Islands, and Pleistocene and Recent examples from the Kermadec Islands, are assigned to Thecidellina maxilla. The type specimen of the Miocene Thecidium australe, from Muddy Creek, Victoria, Australia, is shown to be Lacazella, rather than Thecidellina. The Recent species Thecidellina japonica from Japan is closely related to T maxilla, but not to the New Zealand Paleogene species as previously suggested.