Austrocochlea constricta
A marine snail endemic to southern Australia with a thick, sculptured shell.
Austrocochlea constricta goes by several common names: southern periwinkle, common periwinkle, or ribbon monodonta. This sea snail is a marine gastropod mollusk belonging to the family Trochidae, the top snails. It is found only in Australian waters, along the coasts of New South Wales, South Australia, Tasmania, Victoria, and Western Australia.
The shell is thick, solid, and lacks an opening at its base. It reaches a height of 15 to 32 mm and a diameter of 22 to 28 mm. Its color is a dull ashen or whitish, often marked with black zigzag lines and stripes, or with spiral bands or stripes of black, though it can sometimes be nearly a single color. The conical spire has a sharp tip, and there are about five convex whorls. The first whorl is eroded, and the second-to-last whorl has three very strong spiral ridges. The body whorl bears about seven strong keels. The aperture is slanted. The outer and basal lips are either thick and lined with ridges on the inside, or rather thin and slightly grooved where the main keels sit. The short columella is slanted, with a small tooth at its base, and spreads into a strong callus on the parietal wall at its insertion.
Quick Facts
- Taxon
- Austrocochlea constricta
Facts from the source article.
Lore & Background
The shell of Austrocochlea constricta is thick, solid, and imperforate, with a lusterless ashen or whitish color obscurely marked with black zigzag lines and stripes, or with spiral articulated zones or spiral stripes of black; sometimes it is nearly unicolored. The spire is conical with an acute apex, and the about five whorls are convex. The first whorl is eroded, the penultimate is very strongly spirally tricostate, and the body whorl has about seven strong carinae. The aperture is oblique, and the outer and basal lips are either thick and multilirate within, or rather thin and slightly furrowed at the places of the principal carinae. The short columella is oblique, subdentate at its base and at the insertion spreading in a strong callus upon the parietal wall.
Reader's Guide
Austrocochlea constricta is a well-documented species in the family Trochidae, with its description and distribution recorded in numerous 19th- and 20th-century works, including those by Dillwyn (1817), Menke (1829), Quoy & Gaimard (1834), Adams (1853), Chenu (1859), Tenison-Woods (1877), Fischer (1878), Pritchard & Gatliff (1902), Hedley (1917), Cotton & Godfrey (1934), Cotton (1959), Macpherson (1962), Iredale & McMichael (1962), Ludbrook (1978), and Wilson (1993). Its shell morphology—with strong carinae, a tricostate penultimate whorl, and variable color patterns—has been consistently described across these references. The species is endemic to Australian waters, specifically recorded from New South Wales, South Australia, Tasmania, Victoria, and Western Australia. Its presence in multiple state faunal lists and Quaternary mollusc studies underscores its significance as a characteristic trochid of southern Australian marine environments.
Did You Know?
- The shell height varies between 15 mm and 32 mm, and its diameter between 22 mm and 28 mm.
- The penultimate whorl is very strongly spirally tricostate.
- The species is endemic to Australia, occurring off New South Wales, South Australia, Tasmania, Victoria, and Western Australia.
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