Clanculus gemmulifer
A marine top snail with beaded red shell and black-and-white dots.
Clanculus gemmulifer is a marine gastropod mollusk belonging to the Trochidae family, commonly known as top snails. Its solid shell is low and cone-shaped, with an angular edge at the periphery and a slightly convex underside. The shell reaches a height of 12 mm and has a red or dull red base color. The surface is sculpted with spiral cords that are cut into smooth, rounded beads. On the upper part of the shell, these cords are slightly narrower than the gaps between them; on the base, they are smaller and about equal in width to the gaps. The body whorl has five rows of beads above the periphery, each dotted with black intervals between two white beads, or alternating black and white beads, while the gaps contain two or three red beads. The base is similarly variegated, though the dots may be brown. The furrows between the bead rows are finely crisscrossed by spiral and oblique raised threads. The spire is straight and conical, with an acute, rose-colored tip and about six whorls. The body whorl bends forward. The aperture is slanted and narrowed by a simple, somewhat compressed fold at the base of the columella, and another near the top of the outer lip, with several small folds in between. The columella twists above and enters deeply into the false umbilicus, whose edge is toothed. The parietal callus is strongly folded.
A subspecies, *Clanculus gemmulifer var. pallidus*, described by H. A. Pilsbry in 1903, has a pale, yellowish-brown tint with indistinct, paler radial flames. Only a few of its spiral ridges have sparse black beads, each between two white ones.
This marine species is found in the Indo-Pacific region and off the coast of Japan.
Quick Facts
- Taxon
- Clanculus gemmulifer
Facts from the source article.
Lore & Background
The shell of Clanculus gemmulifer attains a height of 12 mm and is solid, low-trochiform in shape, angular at the periphery and slightly convex beneath. Its ground color is red or dull red, and the sculpture consists of spiral cords cut into smooth rounded beads. On the upper surface, these cords are a little narrower than the intervals; on the base they are smaller and about equal in width to their intervals. Above the periphery on the body whorl there are five rows of beads, each dotted, either with a black interval between two white beads or with a black and a white bead. The intervals consist of two or three red beads. The base is similarly variegated, though the dots are sometimes brown. Furrows between the bead-rows are finely and densely decussate by spiral and oblique raised striae or threads.
The spire is straightly conic with an acute, roseate apex and about six whorls. The body whorl is deflexed in front. The aperture is oblique and contracted by a simple, rather compressed fold at the foot of the columella and another near the upper end of the outer lip, with several small folds between them. The columella is contorted above and enters deeply the false umbilicus, the margin of which is toothed. The parietal callus is strongly plicate.
A subspecies, Clanculus gemmulifer var. pallidus H. A. Pilsbry, 1903, differs by its pale, yellowish-brown tint and some indistinct, paler, radial flames. Only a few of the lirae have sparse, black beads, each between two white ones.
Reader's Guide
Clanculus gemmulifer is a marine gastropod mollusk in the family Trochidae, documented from the Indo-Pacific and off Japan. Its description, published by H. A. Pilsbry in 1901 in the Proceedings of the Academy of Natural Sciences of Philadelphia, provides detailed morphological features including shell height, shape, color, and sculptural elements such as beaded cords and decussate striae. The species is also known from a subspecies, Clanculus gemmulifer var. pallidus, described by Pilsbry in 1903, which exhibits a pale yellowish-brown tint and sparse black beads. The entry in the reference compendium relies solely on the source article, which notes no further significance or legacy beyond its taxonomic description and distribution. The species is listed in external resources such as the Biodiversity Heritage Library, Encyclopedia of Life, and the World Register of Marine Species, as well as on Gastropods.com. No additional historical or cultural context is provided in the source.
Did You Know?
- The shell height of Clanculus gemmulifer attains 12 mm.
- The apex of the shell is described as acute and roseate.
- A subspecies, Clanculus gemmulifer var. pallidus, has a pale yellowish-brown tint.
- The species occurs in the Indo-Pacific and off Japan.
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