Nassarius glans

Lore & Background

The shell of Nassarius glans is rather thin, smooth, ovate and conical. Its ground color is whitish, with spots of a more or less dark red, and upon the lower whorl a very large spot of the same tint but deeper. On the convexity of this whorl may be counted nine or ten distant, parallel and transverse lines of a bright chestnut color, sometimes brown, at other times blackish. The spire is composed of eight whorls, the three lower of which are smooth, and the other five marked with small longitudinal folds, slightly arcuated.

The ovate aperture is widened towards the base, which is deeply emarginated, terminated above by a small dilated canal formed by a re-entering angle from the outer lip and a transverse tooth from the left lip. The outer lip is arcuated towards the top, thinner from the middle to the base, and armed in this part with five conical, pointed teeth, the lowest of which are longest. It is ornamented in the interior with a great number of small, very fine transverse striae. The left lip forms a plate which laps over upon the body of the shell, and gives rise to a small projecting keel, terminated below by a pointed and oblique tooth, from whence a rounded fold is given out, observed to wind spirally into the cavity.

Subspecies include Nassarius glans glans (Linnaeus, 1758) and Nassarius glans particeps (Hedley, 1915). Nassarius glans fenwicki Kilburn, 1972 is considered a synonym of Nassarius fenwicki Kilburn, 1972.

Reader's Guide

Nassarius glans is a representative of the Nassariidae family, commonly known as Nassa mud snails or dog whelks. Its shell, ranging from 15 mm to 50 mm in length, exhibits a complex pattern of red spots and chestnut lines, with a spire of eight whorls showing smooth lower whorls and longitudinally folded upper whorls. The aperture is distinctive, with five conical teeth on the outer lip and a left lip forming a plate that laps over the body, ending in a pointed tooth and a spiraling fold. The species occurs in the Red Sea, the Indian Ocean off Réunion, Mauritius and the Mascarene Basin, and the Indo-West Pacific. The taxonomic treatment includes two recognized subspecies, with Nassarius glans fenwicki considered a synonym of Nassarius fenwicki. The detailed description of the shell morphology—including the number and arrangement of teeth, the transverse striae, and the keel—provides a clear basis for identification within the genus.

Did You Know?

• The shell length of Nassarius glans varies between 15 mm and 50 mm.
• Nassarius glans fenwicki is considered a synonym of Nassarius fenwicki.