Westralunio carteri is a species of freshwater bivalve in the Hyriidae

Hyriidae

Hyriidae is a family of pearly freshwater mussels in the order Unionoida native to South America, Australia, New Zealand and New Guinea. Like all members of that order, they go through a larval stage that is parasitic on fish. The classification recognized by Banarescu uses three subfamilies...

 family. It is endemic to Western Australia

Australia

Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...

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Reproduction

Mature females have specialized gill

Gill

A gill is a respiratory organ found in many aquatic organisms that extracts dissolved oxygen from water, afterward excreting carbon dioxide. The gills of some species such as hermit crabs have adapted to allow respiration on land provided they are kept moist...

 structures known as marsupia. These contain the eggs

Egg (biology)

An egg is an organic vessel in which an embryo first begins to develop. In most birds, reptiles, insects, molluscs, fish, and monotremes, an egg is the zygote, resulting from fertilization of the ovum, which is expelled from the body and permitted to develop outside the body until the developing...

 as they are fertilized and develop into larva

Larva

A larva is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle...

e. Once the larvae reach a particular point in maturity the female releases them into the surrounding water where they attach to a fish

Fish

Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...

by means of a 'larval tooth'. Similar species attract fish by means of a lure in order to insure the young have a place to attach, however, this process has not been fully documented for this species. Larvae live as parasites on the host fish for a period of time as they develop. Once fully grown, they detach themselves from the host.

Source

• Mollusc Specialist Group 1996. Westralunio carteri. 2006 IUCN Red List of Threatened Species. Downloaded on 7 August 2007.
• The western Australia Mussel Watch website http://www.musselwatchwa.com/freshwater-mussels.html