Clanculus undatus

Lore & Background

The shell of Clanculus undatus has a depressed conoid shape, excavated and false-umbilicate in the center beneath. Its coloration is cinereous or rose, with radial stripes of brown or black that are sometimes broken into irregular maculations, especially on the base. The about 6 whorls are convex around the upper part, then flattened, obtusely angulate at the periphery. The base is flattened and concave toward the center, and the sutures are subcanaliculate. The acute apex is eroded.

The following whorls are finely granose in spiral series, of which there are 10 to 12 on each whorl. The body whorl is somewhat deflected anteriorly, bearing about 30 spiral granose ridges, very close and fine upon and below the periphery, coarser above and around the umbilicus, with the interstices obliquely striate. The oblique aperture is tetragonal, with outer and basal lips thickened and plicate within. The oblique columella is inserted nearly in the bottom of the broad umbilical excavation, its edge reflexed and bearing about 10 denticles, twisted near the insertion, terminating below in a simple tooth. The parietal tract is wrinkled. The umbilicus has a plicate border, and in the middle a strong, sometimes crenulate, spiral funicle.

This marine species is endemic to Australia and occurs off New South Wales, South Australia, Tasmania, Victoria and Western Australia.

Reader's Guide

Clanculus undatus is notable as one of the largest species within the genus Clanculus, with a shell size ranging from 20 mm to 40 mm. Its description in the source article provides detailed morphological features, including the depressed conoid shape, false-umbilicate base, and the characteristic granose spiral ridges. The species exhibits variable coloration, being cinereous or rose with brown or black radial stripes that may break into irregular maculations. The shell structure includes about 6 whorls, a tetragonal aperture, and a columella with about 10 denticles. The umbilicus features a plicate border and a strong, sometimes crenulate, spiral funicle. The species is endemic to Australia, with records from New South Wales, South Australia, Tasmania, Victoria, and Western Australia. Its significance lies in its contribution to the understanding of trochid diversity in Australian waters, as documented in references such as Wilson (1993) and Jansen (1995). The detailed anatomical description aids in distinguishing it from other Clanculus species.

Did You Know?

• The shell size of Clanculus undatus varies between 20 mm and 40 mm.
• It is one of the largest species of the genus Clanculus.
• The body whorl bears about 30 spiral granose ridges.