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Wavy Top Shell Austrocochlea concamerata

Form:photo of Wavy Top Shells

The shell of the Wavy Top Shell is more wide than it is high. The shell is thick, round, smooth, and cone shaped. It is less tall than it's close relation, the Zebra Top Shell, A. constricta.

The sculpture of this shell consists of many spiral ribs and uneven cross striations.

There is a single tooth at the base of the columella. The aperture cover is called an operculum which is horny and round. The Wavy Top Shell is distinguished by its flatter shell, stronger ribbing, and yellow spotted or streaked interior.


The Wavy Top Shell is black in colour, marked with yellow spots on the spiral ribs. The lip edge is marked with black and yellow. The shell interior and columella are white.




Wood, 1828




20-25 mm diameter


Wavy Top Shell distribution mapThe Wavy Top Shell ranges from New South Wales, across Victoria, Tasmania, South Australia and Western Australia, to the Houtman Abrolhos.


The Wavy Top Shell is found at mid- to high-tide levels on exposed rock surfaces on medium to high energy shores. It is a gregarious species, often be found in large numbers. It hides in cracks or clusters under rock ledges.


The Wavy Top Shell occurs with its close relations, the Zebra Top Shell A. porcata and the Ribbed Top Shell, A. constricta, but prefers more sheltered habitats.


Other common names are the Wavy Periwinkle, Speckled Periwinkle, or Southern Periwinkle. Another scientific name is Diloma (Fractarmilla) concamerata, .

Bennett, I. (1987) W. J. Dakin's classic study: Australian Seashores. p. 164, Angus & Robertson, Sydney.

Davey, K. (1998) A Photographic Guide to Seashore Life of Australia. p. 89, New Holland, Sydney.

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

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. p. 38, Museum of Victoria, Melbourne.

Macpherson, J. H. & Gabriel, C. J. (1962) Marine Molluscs of Victoria. p. 69, Melbourne University Press & The National Museum of Victoria.

Shepherd, S. A. & Thomas, I. M. (1982) Marine Invertebrates of Victoria, Pt. 2.p. 555, 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. p. 36, A. H. & A. W. Reed, Sydney.

Top Shells & Relatives

Zebra Top Shell
Ribbed Top Shell
Wavy Top Shell

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photo of Keith DaveyLife on Australian Seashores
by Keith Davey (C) 2000

Learning Consultant - Media
The University of Newcastle

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Scientific Consultant: Phil Colman
site created 01.01.98 : updated 01.04.2000