Nassarius crassiusculus

Nassarius crassiusculus is a marine gastropod mollusk belonging to the family Nassariidae, the group known as Nassa mud snails or dog whelks. Its taxonomic history is noteworthy: it was originally described as Buccinum elegans, but that name was later ruled nomenclaturally invalid, so the replacement name Nassarius crassiusculus was adopted. The shell is thick, ovate, conical, smooth, and glossy, with a whitish base color decorated by numerous wavy reddish longitudinal lines.

The spire consists of eight or nine convex whorls; the upper whorls are plaited, while the lower ones bear alternating white and brown spots or blotches around the suture. A slightly darker band runs across the body whorl, whose base has five or six distinct transverse grooves. The aperture is white and ovate, with a sort of canal at the top indicated by a transverse ridge on the left lip.

The outer lip is thick, finely toothed toward the base, and deeply grooved inside. The columella is curved, with a spirally folded base; the left lip extends slightly onto the shell body, forming a small projecting keel ending in tiny drops and a raised point. This species is found in the Indian Ocean off the Seychelles.