American Spider Crab

Pyromaia tuberculata

Systematics: Brachyura Family Majidae

Distinguishing Characters:
The carapace is up to 20mm long, pear shaped with a single spine projecting forwards from the front. All walking legs are very long and spindly.

Habitat and Distribution:
This species is found from the shore line down to a depth of 20 metres in Australia. This exotic species found in Port Phillip Bay and Cockburn Sound is originally from western North America.

General Biology:
The species was first found in Australia in 1987 and is now common on the muddy floor of Port Phillip Bay. It is a native of North America which found its way recently to Japan and from there to New Zealand and southern Australia. Ships certainly played a part in transport of the species. Probably its planktonic larvae ride in the ballast water and grow to adults in their new home when the ballast water was discharged. The effect of this addition to the fauna on native species is not known.