Clanculus leucomphalus
A marine snail endemic to southern Australia with a white umbilicus.
Clanculus leucomphalus is a marine snail, a gastropod mollusk belonging to the Trochidae family, commonly known as top snails. This species is found only in Australian waters, specifically off the coasts of South Australia, Tasmania, Victoria, and Western Australia.
The shell, which ranges from 10 to 14 mm in size, is relatively thin and has a depressed conical shape. Its smooth protoconch consists of one and a half whorls. The shell has six sloping, convex whorls that increase rapidly in size. On the penultimate whorl, there are eight tightly packed spiral rows of smooth, oval granules. The body whorl features ten spiral rows of granules above the sharply angled edge. The granules in the row just below the suture are noticeably larger and aligned axially, while the others are spirally oval. On the base, ten rows of flatter, more square, and more densely packed granules appear. Oblique axial striae are crowded between the granules on the spire but are absent on the base.
The aperture is quadrate and oblique. The outer lip is scalloped and has teeth just inside the margin opposite each spiral ridge; beyond this, it is thickened and wrinkled, and the throat is ridged and pearly. The basal lip is also scalloped, thickened inside, and bears five teeth that gradually enlarge toward the columella. The columella is oblique and nearly straight, ending below in a prominent, obliquely furrowed (but not split) tooth. A large tubercle sits at the junction of its upper and middle thirds, and a flange runs its entire length, curving toward the umbilicus. The umbilicus is wide and deep, with a funicle winding up its outer side to the tubercle on the columella. The umbilical border overhangs and has six medium-sized tubercles, edged by a flat, axially incised spiral ridge with a small thread on each side.
The shell’s color is light ashen grey, with faint flames of deeper grey or buff, and many small pink dots on the second and third whorls. The umbilicus and its margin are pure white, while the aperture is pearly green.
Quick Facts
- Taxon
- Clanculus leucomphalus
Facts from the source article.
Lore & Background
The original description of Clanculus leucomphalus was provided by Joseph Verco. The shell is rather thin and has a depressed conic shape, with a smooth protoconch of 1½ whorls and six sloping convex whorls that increase rapidly in size. The penultimate whorl bears eight close-set spiral rows of smooth ovate granules, while the body whorl has ten spiral rows above the acutely angled periphery. The granules of the infrasutural row are much larger and placed axially, the rest spirally ovate. On the base, ten rows of flatter, more quadrate, and more close-set granules are present, with oblique axial striae crowding between the granules on the spire but obsolete on the base.
The aperture is quadrate oblique; the outer lip is crenulate and toothed just within the margin opposite each spiral lira, thickened and wrinkled within, and lirate and nacreous in the throat. The basal lip is crenulate, thickened within with five teeth gradually enlarging towards the columella. The columella is oblique, nearly straight, ending below in a prominent, obliquely furrowed but not bifid tooth, with a large tubercle at the junction of its upper and middle third, and with a flange throughout its whole length bent towards the umbilicus. The umbilicus is wide and deep, with a funicle winding up its outer side to the tubercle on the columella; the umbilical border overhangs and has six medium-sized tubercles, margined by a flat, axially incised, spiral lira with a threadlet on either side.
The colour of the shell is light ashen-grey, with obscure flames of deeper grey or buff, and with numerous small pink dots on the second and third whorls. The umbilicus and its margin are pure white, and the aperture is nacreous green.
Reader's Guide
Clanculus leucomphalus is notable for its detailed shell morphology as described by Joseph Verco. The species is endemic to Australia, recorded from South Australia, Tasmania, Victoria and Western Australia. Its shell size ranges from 10 mm to 14 mm. The description emphasizes the granulation patterns: eight spiral rows on the penultimate whorl, ten rows on the body whorl above the periphery, and ten rows on the base with flatter granules. The columella features a prominent tooth and a tubercle, and the umbilicus is wide and deep with a funicle and six tubercles on its border. The colouration includes light ashen-grey with deeper grey or buff flames and pink dots on the second and third whorls, while the umbilicus and its margin are pure white. The aperture is nacreous green. This species contributes to the understanding of trochid diversity in Australian waters and has been referenced in multiple works, including those by Cotton, Gabriel, Macpherson, Wilson, and Jansen.
Did You Know?
- The shell size of Clanculus leucomphalus varies between 10 mm and 14 mm.
- This species is endemic to Australia, occurring off South Australia, Tasmania, Victoria and Western Australia.
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