ENDEMIC LAND SNAILS FROM THE PACIFIC ISLANDS AND THE MUSEUM RECORD: DOCUMENTING AND DATING THE EXTINCTION OF THE TERRESTRIAL ASSIMINEIDAE OF THE GAMBIER ISLANDS

Abstract

Two species of terrestrial Assimineidae historically inhabited the Gambier Islands, eastern Polynesia. Both were endemic to the island group and are now extinct. One is a new species of Cyclomorpha, C. secessa n. sp., which was already extinct when it was first collected in 1934. The other is Omphalotropis margarita, a giant species of Omphalotropis, which is represented in museums by material collected alive in the nineteenth century. It was originally described in error from Rapa and the ‘Fox Islands’, but is here shown to have probably been collected on Akamaru, the first European settlement in the Gambier Islands. At least 90 historical specimens in eight museums together suggest that the species became extinct between the 1850s and the early 1900s. Literature and museum records of Cyclomorpha flava from the Gambier Islands are regarded as erroneous; that species is endemic to the western Tuamotus and has, for decades, been used in Polynesian shell craft.