Nassarius distortus
A polished Indo-West Pacific snail with rose bands and tubercled suture.
Nassarius distortus, commonly called the distorted nassa, is a marine gastropod mollusc belonging to the family Nassariidae, which includes the Nassa mud snails and dog whelks. Its shell, which ranges from 18 mm to 35 mm in size, is ovate, conical, smooth, polished, and whitish. Beneath the suture runs a rose-colored band, and three more such bands encircle the middle of the lowest whorl; the central band is broader and more noticeable. The spire consists of seven slightly convex whorls, each adorned with numerous, slightly raised longitudinal ribs that resemble folds. The upper edge of each whorl is somewhat flattened. At the base of the lowest whorl, two distinct ridges are present. The suture is bordered by rounded tubercles positioned between the folds, forming a necklace-like pattern. The white aperture is ovate and narrowed above by a transverse fold of the callosity. The outer lip is slightly truncated, finely toothed along the lower edge, and marked internally with transverse striae. The columellar edge is covered by a fairly thick callosity that spreads a little onto the shell’s belly. This species has a wide distribution across the Indo-West Pacific, including off the coast of Queensland, Australia.
Quick Facts
- Genus
- Nassarius
- Species
- distortus
Facts from the source article.
Lore & Background
The shell of Nassarius distortus is smooth, polished, and whitish, with a decurrent band of rose color beneath the suture and three additional rose bands surrounding the middle of the lowest whorl, the middle band being broader and more apparent. The spire consists of seven slightly convex whorls ornamented with numerous, slightly elevated longitudinal ribs formed like folds. The upper edge of the whorls is a little flattened, and the base of the lowest whorl is accompanied by two distinct ridges. The suture is edged with rounded tubercles situated between each fold, creating a necklace-like appearance. The white aperture is ovate, contracted above by a transverse fold of the callosity. The outer lip is subtruncated, somewhat denticulated on the lower edge, and marked internally with transverse striae. The columella edge is covered by a pretty thick callosity that spreads a little upon the belly of the shell.
Reader's Guide
Nassarius distortus is a well-documented species within the family Nassariidae, recognized for its distinctive shell morphology that includes polished surfaces, rose-colored bands, and a tubercled suture. Its wide distribution across the Indo-West Pacific, including waters off Queensland, Australia, indicates a broad ecological range. The species has been referenced in several taxonomic works, including Adams' 1852 catalogue of Nassa species and Reeve's 1853 monograph, as well as later studies by Dautzenberg (1929), Cernohorsky (1984), and Wilson (1994). These references contribute to the systematic understanding of the Nassariidae family. The shell's size range of 18 to 35 mm and its ornate features make it a recognizable subject in malacological collections. The species' common name, 'distorted nassa,' reflects its characteristic shell form. Its presence in multiple faunal surveys underscores its significance as a representative of Indo-West Pacific marine gastropod diversity.
Did You Know?
- The shell size of Nassarius distortus varies between 18 mm and 35 mm.
- The shell has a decurrent band of rose color beneath the suture and three others around the middle of the lowest whorl.
- The suture is edged with rounded tubercles between each fold, forming a necklace-like pattern.
- This species occurs in the Indo-West Pacific and off Australia (Queensland).
More in Marine Snails: Ceriths, Nassas and Conchs, Part 2 1-24
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