Hairy Triton or Whelk
The Hairy Triton has an extensive distribution range including the eastern and western Atlantic Ocean, Mediterranean sea, eastern Pacific Ocean, South Africa, Japan, Australia, and New Zealand. In Australia, the Hairy Triton has a southern temperate Australian distribution. Its range includes northern NSW, around southern shores including Vic, northern Tas, and SA to Lancelin, WA (NSW, VIC, TAS, SA, WA).Features:
The Hairy Triton has a large, thick, strongly ridged, scaly shell that is fusiform, which means broadly tapered at both ends. The shell grows to a length of 100-140mm. Thick, noduled, round spiral ribs sculpture the shell. The ribs are crossed by fine spiral and axial patterned striations. Paired rows of white coloured denticles or teeth occur around the inner margin of the outer lip of the aperture. The white coloured columella has irregular shaped folds. Prominent axial ridges occur on the whorls that mark the edge of the outer lip during shell growth.
The mollusc's foot is distinctive, being cream coloured with numerous round brown-coloured spots. The shell is brown outside, and white coloured inside. The hairy, bristled, dark-brown periostracum covering is an excellent shell camouflage.Ecology/Way of Life:
The Hairy Triton occurs on reefs at low tide levels and below to 18 metres. It wedges itself into crevices amongst same coloured algae. In the more northern parts of its range, such as near Moreton Bay, Qld, and in northern NSW, it is a serious pest to oyster beds in estuaries. Here it is known as the Hairy Oyster Borer, but this is a misnomer. This mollusc has the ability to somehow paralyse its prey, causing the bivalves to open their shell valves to be consumed. Their egg masses are hemispherical, appearing like the skin of half a peeled orange. The egg-mass appears to be made up of a semi-translucent horn-like material. The little egg capsules are embedded on the inner inward-curving surface.Interaction with Humans/Threats:
The Hairy Triton or Hairy Oyster Borer is a serious pest to oyster farmers in south-eastern Queensland and north-east NSW, who would like to see it threatened, or certainly less abundant.Other Comments:
Cymatium parthenopea, von Salis, 1793. Also known as Monoplex australasiae, Perry, 1811, Septa parthenopea, Septa (Monoplex) parthenopeum and Austrosassa parthenopea. Also known as the Hairy Oyster Borer.
Cymatium may come from the Latin word cymbalum, meaning the hollow of a vessel, which describes the egg mass. Parthenopea may come from the Greek word parthenos, meaning a virgin, but is more likely named after the Parthenon, the temple to the goddess Athene on the Acropolis at Athens.Further Reading:
Bennett, I. (1987). W. J. Dakin's classic study: Australian Seashores: a guide to the temperate shores for the beach-lover, the naturalist, the shore-fisherman and the student. p.289, Angus & Robertson.
Edgar, G.J. (1997). Australian Marine Life: the plants and animals of temperate waters. p.256, Reed.
Jansen, P. (2000), Seashells of South-East Australia. p.42, Capricornia Publications.
Macpherson, J. H. & Gabriel, C. J. (1962). Marine Molluscs of Victoria. p.162, Melbourne University Press. (As the Southern Rock Whelk, Monoplex australasiae).
Wells, F. E. & Bryce, C. W. (1988). Seashells of Western Australia. Western Australian Museum. (As Septa parthenopea).
Wilson, B. (1993) Australian Marine Shells. Prosobranch gastropods. Odyssey Publishing.
Wilson, B. R. & Gillett, K. (1979). A Field Guide to Australian Shells: Prosobranch Gastropods. Reed. (As Septa (Monoplex) parthenopea).
Text, map & photograph by Keith Davey.Sponsorship welcomed:
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