Tonna dolium

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Tonna dolium, commonly known as the spotted tun, is a large sea snail in the family Tonnidae (tun shells). It lives in the Indo-West Pacific.

Description
- Shell size: about 10 to 18 cm (100–181 mm).
- Shape: ovate-globose with a short spire, six whorls, and a large, very convex body whorl.
- Sculpture: the whorls have wide, distant ribs (about ten on the body whorl); narrower ribs occur in the furrows.
- Color: the shell is white with a grayish tinge, sometimes rose-colored. The ribs bear alternating white and red (often orange) spots, giving a decorative pattern.
- Aperture and lip: the opening is very large; the inside is chestnut-colored. The outer lip is thin and notched; the inner lip is faint toward the base. The umbilicus is poorly developed. The columella is spirally twisted and has external longitudinal ribs.
- Distinguishing features: wide, distant ribs and furrows make it easy to recognize.

Distribution
- This species is found in the Indo-West Pacific, including waters off Tanzania, the Mascarene Basin, and around the Philippines.

Taxonomy and synonyms
- Binomial name: Tonna dolium (Lamarck, 1822).
- Common synonyms include Buccinum dolium (Linnaeus, 1758) as the original combination, Dolium maculatum, and several other reclassifications in related genera.
- Other names on record include Cadus dolium and Dolium cassis among various recombinations.

Habitat
- Tonna dolium is a marine gastropod that inhabits sea environments in its tropical and subtropical range.