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
Tudicula spirata or closely related juvenile Tonna perdix
Shell Type
Gastropod (univalve), whole shell, spiral shape
Family
Tonnidae (Tun shell family)
Size
Approximately 1 to 1.5 inches, likely a juvenile specimen. Adults of the species typically range from 3 to 6 inches.
Color & Pattern
Milky white base coloration adorned with distinct, evenly spaced reddish-brown spots arranged in spiral rows. The colors appear natural and fairly well-preserved with minor sun-bleaching.
Rarity
Common
Habitat
Shallow subtidal waters, sandy bottoms, and coral reef peripheries, typically marine.
Geographic Range
Indo-Pacific region, spanning from East Africa across the Indian Ocean to Polynesia and Hawaii.
Description
A charming, lightweight, rounded shell featuring a low spire and a very large, expanded body whorl. The surface exhibits delicate spiral ridges and striking brown polka-dot markings, giving it a playful and recognizable appearance.
Key Features
Thin yet surprisingly resilient shell wall, large inflated body whorl, absence of an operculum, and distinct spiral rows of reddish-brown square or round spots.
Collector Value
Low to moderate value. While very popular among casual beachcombers and beginner collectors due to their attractive spotted patterns, common species like this are inexpensive and widely available.
Condition Notes
Good condition for a beach-worn specimen. Shows minor wear around the apex and aperture lip, but the color pattern remains vivid. Grade: Good.
Interesting Facts
Tun shells are voracious predators that feed primarily on sea cucumbers, subduing them with a specialized acidic secretion containing sulfuric acid to dissolve their prey's defenses.
Ecological Role
Acts as an important carnivore in shallow marine and reef ecosystems, helping regulate populations of benthic invertebrates like sea cucumbers.
Similar Species
Other species in the Tonnidae family, such as Tonna dolium (Band Tun), which features banded patterns rather than distinct spots.
Beach Finding Tips
Look along tropical sandy beaches and reef lines after a strong storm or high tide, especially during early morning low tides.