They also have the largest number of recorded extinctions in the last 300 years, recorded by the IUCN (The World Conservation Union) at 284 - far more than the global figure for bird and mammal extinctions in the same period put together.
Non-marine molluscs are of special interest because many species have very restricted ranges, giving rise to conservation concerns. Current Australian Museum researchers have been recording and describing Australian non-marine molluscs with the aim of establishing their conservation status, threats and habitat requirements.
Recent research led by Dr Winston Ponder has focused on hydrobiids, by far the largest group of freshwater molluscs. They are small, usually conical and are of considerable antiquity. The research has shown that some groups of hydrobiids are very diverse. One recently described Tasmanian group contains more than 60 species, some of which have yet to be named. The genus Austropyrgus has been found to contain more than 70 species in Tasmania and south-eastern Australia, and more than 30 other species of hydrobiids have been recorded from caves in Tasmania .
The Australian Museum project is ongoing and has, so far, produced 26 publications with many others in preparation.