Description

The family Tonnidae includes a small number of species with medium-sized to large shells which  are thin for their size, and nearly spherical. The spire is small, while the body whorl is large and well inflated, ending in a very wide aperture. The outer surface is usually sculptured by thick spiral ribs. The animals lack the operculum. Most tun shells can be found living in sand, in the tropics beyond the edge of the coral reef.

Classification

Class: Gastropoda

Clade: Littorinimorpha

Superfamily: Tonnoidea

Family: Tonnidae

 

Major Genera

• Genus: Eudolium
• Genus: Malea
• Genus: Tonna

Malea ringens (Swainson, 1822)
Grinning Tun

Malea pomum (Linnaeus, 1758)
Pacific Grinning Tun
(from Wilson, 1993)

SEE OTHER TUN SHELLS:

SEE A LIVE TUN MOLLUSC LAYING A
RIBBONED EGG MASS,
(Paolo Galbano's web site; photos by Roberto Pirrella)