Chitons

Chitons are considered to be very primitive molluscs. Chitons are a very distinctive group because their protective armour consists of eight separate, usually overlapping, plates or valves held in position by an encircling muscular girdle.

The girdle is often marked with unusual spikes and spines. Chitons are long (elongate), usually flattened, and symmetrical. The Spiculed Chiton Acanthoplera gaimardi (on the left), as its name suggests, has a girdle of blunt spicules.

Chitons are adapted to living on hard rock surfaces. They have a very muscular foot, and when disturbed, can clamp down so that they cannot be dislodged unless their shell is smashed. Chitons can live for one to twenty years, or more.

Chiton sexes are separate, the eggs and sperm being shed into the water where fertilization takes place. The Snake-skin Chiton Chiton pelliserpentis (to the right) is a very common chiton on south-eastern Australian shores.

Chitons are particularly abundant in Australia, and the shores of southern Australia have the most species in the world. It is believed that Chitons first evolved there. Chitons belong to the class Polyplacophora.

References

Bennett, I. (1987) W.J. Dakin's classic study: Australian Seashores. Angus & Robertson, Sydney.

Davey, K. (1998) A Photographic Guide to Seashore Life of Australia. New Holland, Sydney.

Edgar, G. J. (1997) Australian Marine Life: the plants and animals of temperate waters. Reed Books, Kew.

Jones, D. & Morgan, G. (1994) A Field Guide to Crustaceans of Australian Waters. Reed, Chatswood.

Quinn, G. P., Wescott, G. C. & Synnot, R. N. (1992) Life on the Rocky Shores of South-Eastern Australia: an illustrated field guide. Victorian National Parks Association, Melbourne.

Marine Research Group of Victoria (1984) Coastal Invertebrates of Victoria: an atlas of selected species. Museum of Victoria, Melbourne.

Macpherson, J. H. & Gabriel, C. J. (1962) Marine Molluscs of Victoria. Melbourne University Press & The National Museum of Victoria.

Shepherd, S. A. & Thomas, I. M. (1982) Marine Invertebrates of Victoria, Pt. 1. South Australian Government Printer, Adelaide.

Underwood, A. J. & Chapman, M. G. (1993) Seashores: a beachcomber's guide. New South Wales University Press, Sydney.

Wilson, B. R. & Gillett, K. (1979) A field guide to Australian Shells: Prosobranch Gastropods. A.H. & A.W. Reed, Sydney.

Womersley, H. B. S. (1987) The Marine Benthic Flora of Southern Australia. pt.1 , South Australian Government Printer, Adelaide.

Molluscs
Chitons

Spiculed Chiton
Snake-skinned Chiton
Yellow Chiton
Mysterious Chiton

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