The Hexagon Tusk Shell, Dentalium neohexagonum, is a representative Scaphopoda of the Tusk Shells of the Dentalidae Family.

Tusk Shell within the Scaphopods Class derive their name from their resemblance to elephant tusks. They are long, narrow, tapering, tubes. They are open at both ends. Most Tusk Shells are curved. Externally, they may be smooth and shiny, dull and chalky, or marked by lengthwise striations. Most are white, but a few tropical species are light green or pink. Tusk Shells range in size from 0.5 cm (0.25 inches) to 15 cm (5.9 inches). Most species are less than 5 cm (2.0 inches) in length. As Tusk Shells grow from the wide anterior end, part of the narrow posterior end dissolves away. As a result, the posterior end may change in shape throughout the animal’s life. Tusk Shells have long been used a shell money and jewelry by Native Americans and Mediterranean cultures.

Tusk Shells reside within sand and mud substrate and plough through sand or mud, using a modified foot. The foot projects from the wider opening of the shell. This cone-shaped foot gives the shell its Latin name-“Boat-footed”.  Some species bury several shell lengths beneath the surface of the substrate. Other species are only slightly buried, with their narrow end projecting above the surface of the substrate. Tusk Shells feed on foraminifera, mollusk larvae, and detritus, which they sift from the sand. Tusk Shells live in marine environments from the subtidal zone to very deep water, exceeding 4,570 m (14,990 feet). They are found worldwide in tropical and temperate seas.

The Scaphopoda Class has two orders Dentaliida and Gadilida. The Dentaliid shells are generally rough textured with strongly ribs. As a defense mechanism they freeze in place when they sense vibrations anywhere around them making them difficult to detect by animals such as rays or ratfish, which can sense the electrical signals given off by muscle movement. Gadilida shells are usually glassy-smooth and narrow, with a reduced aperture. This along with other structures of their anatomy allows them to move with surprising speed through loose sediment to escape potential bottom-dwelling predators.

At present the Scapopoda Class consists of twelve families and about three hundred and seven-five extant species, and another four hundred to nine hundred species being extinct. The earliest scaphopod fossils date from the Devonian Period, three hundred fifty-nine to four hundred nineteen million years ago. About seventeen species in the Dentalidae Family are found along the West coast of Mexico.