Calthalotia arruensis
A conical, tubercled sea snail endemic to Australian waters.
Calthalotia arruensis is a sea snail belonging to the family Trochidae. Its shell is strong, opaque, and conical, with a flat base and a keeled shape. The surface is covered in small, round tubercles arranged in eight spiral rows on each whorl. The first two rows have larger tubercles, separated from the next three rows by clear depressions. The lowest three rows are more tightly packed but slightly protruding, especially the central and largest row. On the base, about nine spiral threads bear smaller tubercles, with weaker threads in between that become fainter toward the center. The tubercles are smooth and polished, while the rest of the surface is finely textured with oblique puckering.
The shell is white, with grayish-purple patches above and purplish-pink spots on the base. The spire is tall and sharply pointed, with a concave conical slope slightly interrupted at the sutures by the two upper rows of tubercles. There are about ten flat whorls that increase steadily in size. The suture is faint but visible, bordered above by a slight keel and below by a double row of large tubercles. The aperture is small, square, and very oblique. The outer lip is sharp but sturdy, and the inner lip is reinforced internally by a porcelaneous nacre buttress that ends abruptly near the columella tip, forming a tooth. The columella is beveled to a sharp edge and pressed back against the umbilicus, which it fully closes, leaving only a central depression and a post-columellar furrow. The operculum is thin, yellow, and normal in form.
This marine species is found only in Australia, off the coast of Queensland.
Quick Facts
- Taxon
- Calthalotia arruensis
Facts from the source article.
Lore & Background
The shell of Calthalotia arruensis is strong, opaque, conical, carinated, and flat on the base. It is covered with tubercles and colored with gray and pink. Its sculpture shows eight spiral rows of small round tubercles on each whorl; the first two rows have larger tubercles, parted by distinct depressions, while the lowest three rows are closer together but project slightly. On the base there are about nine less strongly tuberculated spiral threads with feebler threads between. The tubercles are smooth and polished, but the intervening surface is sharply fretted with fine oblique puckerings. The color is white, flecked above with grayish-purple patches and closely spotted with purplish-pink on the base. The spire is high and sharp pointed, containing about ten flat whorls that increase regularly in size. The aperture is rather small, square, and very oblique. The outer lip is sharp but strong; the inner lip is strengthened internally by a buttress of porcelaneous nacre that ends abruptly, forming a tooth. The columella is beveled to a sharp edge and pressed back on the umbilicus, which it completely closes. The operculum is thin, yellow, and normal.
Reader's Guide
The significance of Calthalotia arruensis lies in its detailed morphological description, which contributes to the taxonomic understanding of the family Trochidae. The species is notable for its distinctive shell sculpture, including eight spiral rows of tubercles on each whorl and about nine tuberculated spiral threads on the base, with fine oblique puckerings on the intervening surface. Its color pattern—white with grayish-purple patches above and purplish-pink spots on the base—is characteristic. The shell's structure, such as the high sharp spire, the small oblique aperture, and the closed umbilicus with a post-columellar furrow, provides diagnostic features for identification. The species is endemic to Australia, specifically off Queensland, and its description is based on historical collections, including those from the H.M.S. Challenger expedition. Its legacy is as a well-documented example of a trochid snail from Australian waters, with its morphology recorded in detail by early malacologists.
Did You Know?
- The base has about nine less strongly tuberculated spiral threads.
- The species is endemic to Australia and occurs off Queensland.
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