Key to Australian Freshwater and Terrestrial Invertebrates
Phylum Mollusca
Class Gastropoda
Informal group Pulmonata
Informal group Basommatophora
Family Glacidorbidae
Common name: freshwater snails
Overview
Glacidorbidae are minute snails with a coiled shell and flat or near-flat spire. All species have an operculum
Distribution and diversity
The only true freshwater family in the Basommatophora is the Glacidorbidae. The Glacidorbidae are a Gondwanan family with 19 species in four genera occurring in south-east Australia, south-west Australia and Tasmania and single a species from southern Chile. Another superfamily often placed in the Basommatophora, the Amphiboloidea, includes several species in Australia that inhabit estuaries and salt marshes.
Life cycle
Glacidorbidae are hermaphroditic with many species requiring fertilisation from another individual, while others can self fertilise. Some species can reproduce parthenogenetically, laying unfertilised eggs that develop into adults. Eggs are typically laid in a gelatinous capsule that is attached to plants or other appropriate surfaces. Development is advanced, with no free-swimming larval stage and juveniles emerge from the capsule looking like miniature adults. In Glacidorbidae, eggs and larvae are brooded within the female body.
Feeding
Basommatophora are herbivorous or omnivorous, mostly grazing on living and dead plant matter, and algae, with some species also scavenging on the carcases of dead animals. The only species studied in detail, Glacidorbis hedleyi, feeds on the tissues of freshly dead animals.
Ecology
Glacidorbidae inhabit ephermeral habitats to permanent to semi-permanent streams or swamps, bogs, streams and rivers where they are normally found on macrophytes, moss, roots, pieces of wood, decaying leaves or sometimes under stones or on the soft sediments on the bottom.
