Partridge Tun, also known as the Spotted Tun
Phylum: Mollusca, Class: Gastropoda, Order: Littorinimorpha, Family: Tonnidae, Genus: Tonna, Species: Tonna perdix · Tonnidae (Tun shell family) · Gastropod (univalve), whole shell, spiral shape
Species
Tonna perdix
Shell Type
Gastropod (univalve), whole shell, spiral shape
Family
Tonnidae (Tun shell family)
Size
Approximately 2 to 3 inches in the photograph, which is typical for a juvenile or small adult specimen. Fully mature adults of this species typically range from 4 to 6 inches, with exceptional specimens reaching up to 8 inches.
Color & Pattern
The background color is a creamy white to light beige, beautifully adorned with distinct, evenly spaced rows of reddish-brown to dark chestnut square or rectangular spots resembling the plumage of a game bird (partridge). The surface has a glossy, natural sheen with fine spiral ribs.
Rarity
Common; frequently encountered by snorkelers, divers, and occasionally found washed ashore in favorable regions within its natural geographic range.
Habitat
Inhabits shallow subtidal waters down to moderate depths, typically ranging from the intertidal zone to about 30 meters. It is almost exclusively found on sandy bottoms, sand flats, and near coral reefs where it buries itself in the sand during daylight hours.
Geographic Range
Widespread throughout the Indo-Pacific region, spanning from East Africa and the Red Sea across to Polynesia, Hawaii, and northern Australia.
Description
An exceptionally attractive and lightweight shell characterized by its rounded, inflated body whorl and relatively small, pointed spire. The surface is sculpted with delicate, low spiral cords that give it a finely textured feel. The aperture is large and wide, lacking an operculum, with a simple outer lip.
Key Features
Inflated, lightweight globular body whorl, small pointed spire, large oval aperture, and the distinctive pattern of square reddish-brown spots arranged in neat spiral rows resembling a checkerboard.
Collector Value
Moderately valued by shell collectors for its pleasing symmetry and striking pattern. While common in its native range, high-grade, gem-quality specimens with intact lips and vibrant patterns are always desirable additions to a cabinet.
Condition Notes
The specimen appears to be in pristine, gem-grade condition with a complete, undamaged spire, vibrant natural coloration, and no visible major chips, cracks, or boring sponge marks.
Interesting Facts
Tun shells are specialized nocturnal predators that feed primarily on sea cucumbers and other echinoderms. They secrete a specialized saliva containing sulfuric acid to subdue and digest their prey.
Ecological Role
Plays an important predatory role in benthic marine ecosystems by helping to regulate sea cucumber and invertebrate populations. It is not currently listed as endangered or heavily regulated.
Similar Species
Tonna maculosa (Atlantic Partridge Tun), which is found in the Western Atlantic and Caribbean rather than the Indo-Pacific, and features slightly different spot distributions and color hues.
Beach Finding Tips
Best found by exploring sandy areas adjacent to coral reefs at low tide, or by searching the drift line on tropical Indo-Pacific beaches following heavy storms or high surf events.