Nassarius dorsatus
A marine gastropod with a smooth, conical shell and thick outer lip.
Nassarius dorsatus, called the channeled nassa, is a marine gastropod mollusk belonging to the family Nassariidae—the group that includes Nassa mud snails and dog whelks. Its shell, which is ovate and conical, ranges from 15 mm to 45 mm in length. The surface is smooth and uniformly ashy white. The spire consists of eight whorls; the upper ones are slightly plaited, while the lowest whorl is fairly large and marked with nearly straight, longitudinal lines that are close together and tinged a slightly deeper reddish color. Six or seven furrows decorate the base of the shell. The ovate aperture is white inside, with a fawn-colored interior. The thick outer lip curves toward the base and rises externally into a thick, very prominent margin; it is striated along its entire inner length. The left lip is thick and partly covers the columella, which is adorned with guttules along half its length—the uppermost guttule being much more pronounced than the others. At the columella’s base there is a very prominent fold that ends in a guttule shaped like a flattened point. This marine species occurs in the tropical Western Pacific, off East India, the Philippines, Papua New Guinea, and Australia (New South Wales, the Northern Territory, Queensland, and Western Australia). Two parasites recorded from Australia are *Stephanostomum*-like cercariae: *Cercaria capricornia* VII and *Cercaria capricornia* VIII.
Quick Facts
- Taxon
- Nassarius dorsatus
Facts from the source article.
Lore & Background
The shell of Nassarius dorsatus is ovate and conical, smooth, and of a uniform ashy white color. The spire consists of eight whorls; the upper ones are slightly plaited, while the lowest whorl is pretty large and marked with more or less straight, longitudinal lines that are approximate and of a slightly deeper, reddish color. The base of the shell is ornamented with six or seven furrows. The ovate aperture is white and fawn-colored within. The thick outer lip is arcuated towards the base and elevated exteriorly into a thick, very prominent margin; within, it is striated throughout its whole length. The left lip is thick and partially covers the columella, which is adorned with guttules for one half of its length. The first of these guttules, which is uppermost, is much more marked than the others. At the base of the columella is a very prominent fold, terminated by a guttule formed like a flattened point.
Reader's Guide
Nassarius dorsatus is a well-documented species within the Nassariidae family, noted for its distinctive shell morphology. The species has been described in multiple works, including those by Röding, Gray, Kiener, Reeve, Cernohorsky, and Wilson, reflecting sustained scientific interest. Its distribution across the tropical Western Pacific, from East India to Australia, indicates a broad range in warm marine waters. The shell's characteristics—such as the thick outer lip, striated interior, and columellar guttules—are key features used in identification. The species also serves as a host for parasitic trematodes, specifically Stephanostomum-like cercariae known as Cercaria capricornia VII and Cercaria capricornia VIII, documented from Australia. This parasitic relationship adds to the ecological understanding of the species within its habitat. The channeled nassa remains a subject of study in malacology, contributing to knowledge of nassariid systematics and biodiversity.
Did You Know?
- The shell length of Nassarius dorsatus ranges from 15 mm to 45 mm.
- The columella is adorned with guttules for one half of its length, with the uppermost guttule being much more marked.
- This species hosts Stephanostomum-like cercariae, specifically Cercaria capricornia VII and Cercaria capricornia VIII.
- The outer lip is thick, arcuated towards the base, and elevated into a very prominent margin.
Frequently Asked Questions
What is Nassarius dorsatus?
Nassarius dorsatus, commonly called the channeled nassa, is a marine gastropod mollusk placed in the family Nassariidae, the same group that contains Nassa mud snails and dog whelks.
What does the shell of Nassarius dorsatus look like?
The shell is ovate and conical with a smooth, uniformly ashy white surface. Its spire has eight whorls—the upper ones slightly plaited, the lowest one fairly large and marked with close, nearly straight longitudinal lines tinged a deeper reddish hue—and six or seven furrows run along the base. The aperture is white externally and fawn-colored within.
How large does Nassarius dorsatus grow?
Adult shells of this species range from 15 mm to 45 mm in length, placing it in the moderate size bracket among nassas.
Where can you find Nassarius dorsatus in the wild?
This species is native to the tropical Western Pacific, with records from off East India, the Philippines, Papua New Guinea, and the Australian coast across New South Wales, the Northern Territory, Queensland, and Western Australia.
What distinguishes Nassarius dorsatus from other nassas?
The channeled nassa is set apart by its uniformly ashy white coloration, the close longitudinal lines on its large lowest whorl, the six or seven basal furrows, and a notably thick outer lip.
More in Marine Snails: Ceriths, Nassas and Conchs, Part 2 1-24
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