Callistele calliston
A marine snail with a purple-brown shell and creamy flames.
Callistele calliston, known as the beautiful top shell, is a marine gastropod mollusk in the family Trochidae, with no subfamily assigned. Its shell, described by Jos. C. Verco, reaches 12 mm in height and has a thin, conical form. The spire comprises nine whorls, the first two of which are smooth. The remaining whorls slope straight and are covered with crowded spiral lirae—about 24 on the penultimate whorl—crossed by oblique, crowded growth striae that create a sublenticular pitted texture. The suture is linear, sitting just below a prominent peripheral cord that grades the spire. On the body whorl, the suture descends slightly at the aperture; this whorl bears about 24 spiral threadlets and fine, sinuous, oblique growth striae. The periphery is sharply angular, with a projecting rounded keel that is engraved spirally on its upper surface and crossed adaxially by rounded striae, spaced more widely than the growth striae, and bearing 16 rounded, irregularly spaced tubercles. The base is very flatly rounded, with seven narrow concentric lirae—the inner four closer together—separated by four to six interlirae striae. The umbilicus is narrow and minutely incised axially. The aperture is oblique and roundly quadrate; the outer lip is slightly convex, thin, and smooth inside, with a margin that is sinuously convex below the suture and concave toward the periphery. The basal lip is convex, slightly flared, and smooth inside. The upper third of the columella is concave, the rest straight and obliquely truncate below; a callus at the base partly borders the umbilicus and attaches to the columella along a vertical groove.
The shell is purple-brown, with somewhat oblique, axial, creamy, rhomboidal flames running from suture to suture, nearly matching the background color in area. On the peripheral keel and above the sutures, these flames are replaced by two or three creamy spots, while two or three less distinct white spots occupy the intervals, highlighting the keel’s tubercles. Each whorl is encircled by four articulated color bands: in white areas they appear more opaque white and extend slightly beyond, crossed by narrow vertical or oblique red lines; in purple areas they are a deeper purple tint, crossed by narrow axial white lines. The base is lighter, with the outer six cinguli rose pink and minutely dotted with creamy white.
Quick Facts
- Taxon
- Callistele calliston
Facts from the source article.
Lore & Background
The shell of Callistele calliston is thin, conical, and attains a height of 12 mm. The spire consists of nine whorls, including two smooth apical turns, with straight-sloping whorls bearing crowded spiral lirae—about 24 on the penultimate whorl—crossed by oblique accremental striae that produce sublenticular pitting. The suture is linear, just below a prominent peripheral cord. The body whorl has about 24 spiral threadlets and is crowded with fine sinuous accremental striae. The periphery is acutely angular with a projecting rounded carina, which bears 16 rounded invalid tubercles at somewhat irregular intervals.
The base is very flatly rounded with seven concentric narrow lirae, the inner four closer than the rest. The umbilicus is narrow and minutely axially incised. The aperture is oblique and roundly quadrate; the outer lip is slightly convex, thin, and smooth within. The columella is concave in its upper third, then straight and obliquely truncate below. The operculum is horny, multispiral with a central nucleus, and has a radial cellular fringe-like film over the inner three-fourths of each spiral. The radula formula is ~ .1.5. 1.5.1. ~, with a heart-shaped central rachidian and unicuspidate marginals.
The shell is purple-brown with oblique, axial, creamy, rhomboidal flames extending from suture to suture. On the peripheral carina, these are replaced by creamy spots, and the tubercles are picked out by white spots. Every whorl has four articulated color bands, with deeper purple in the purple areas crossed by narrow axial white lines. The base is lighter, with rose-pink outer cinguli dotted creamy white. The columella and umbilicus are white, bordered outside with green.
Reader's Guide
The significance of Callistele calliston lies in its detailed morphological description by Jos. C. Verco, which provides a comprehensive account of shell structure, color pattern, operculum, and radula. This species is part of the family Trochidae, though unassigned to a subfamily, and its description contributes to the taxonomic understanding of marine gastropods off South Australia. The shell's intricate features—such as the 16 tubercles on the peripheral carina, the multispiral operculum with a cellular fringe, and the radula formula—offer diagnostic characters for identification. The color pattern, with articulated bands and creamy flames, is notable for its complexity. The species is documented in references by Cotton (1959) and Wilson (1993), and its occurrence is restricted to South Australian waters. Its legacy is as a well-characterized example of a trochid snail, with its description serving as a reference for future studies of shell morphology and radular variation in the family.
Did You Know?
- The shell height attains 12 mm.
- The peripheral carina bears 16 rounded invalid tubercles.
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