Amphipods are a diverse group of small, mostly marine animals related to crabs, shrimps and lobsters. Most species are 1-10 mm long, although deep-sea specimens up to 300 mm long have been found. Although amphipods are mostly marine, there are many freshwater ones and a few terrestrial species that live in moist places such as beaches and leaf litter.
Marine amphipods are found at all depths of the ocean, and are mostly benthic animals (bottom dwellers) that burrow into the sand or mud of the sea floor. Others live among algae or seaweed. Amphipod species obtain their food in different ways, including filter feeding, scavenging and feeding on plants or by being obligate associates of other animals.
Amphipods have seven pairs of walking legs, a head with eyes, mouthparts and two pairs of antennae, and gills found on their thorax. The curved body of 'B wirakus' is typical of many amphipods.
Amphipods belong to a group of invertebrate animals called crustaceans that includes crabs, shrimps, yabbies and lobsters as well as an array of smaller animals. Crustaceans come in many sizes and forms, and are usually associated with the tough external skeleton in which their bodies are encased.
This specimen of 'B wirakus' was found in Port Phillip Bay on the south-central Victorian coast. It was identified and named in 1978. This species was among thousands of marine animals collected during the Port Phillip Bay Environmental Surveys conducted by government departments and Museum Victoria. These surveys, in 1969-73 and 1992-96, were concerned with the environmental condition of the Bay and changes in benthic communities. Invaluable information relating to the density and distribution of native and introduced species was obtained, and thousands of previously unknown species were identified.