The species of New Zealand onchidiidae (mollusca, gastropoda) and their distribution

Abstract

The present classification of the New Zealand Onchidiidae into six species is shown to be incorrect. Three of the species, Onchidella patelloides (Quoy and Gaimard), O. irrorata (Gould), O. obscura (Plate), have insufficient differences for separation. They are reclassified under the species name Onchidella nigricans (Quoy and Gaimard). Both O. flavescens (Wissel) and O. campbelli (Filhol) possess sufficient distinctive features for classification as species. The distribution of the Onchidiidae in the austrozealanic region is given. Onchidella campbelli is a southern species occurring in the subantarctic islands of New Zealand, O. flavescens is limited to the east coast of the South Island and Wellington, O. nigricans is ubiquitous in New Zealand and its off‐shore islands and occurs also on the south‐east coast of Australia.