Auger Seashell Identification

Augers are some of the most common shells in North America.

Collecting seashells is a popular pastime for everyone from children to adults, experts to novices. In North America one of the easiest shells to collect is the auger, which is present all along the Mid-Atlantic and Southern Atlantic coastlines, as well as along the Gulf coast, and even Southern California. Augers can also be found as far away as the Galapagos Islands and West Africa.

Species Overview

Auger shells belong to the family Terebridae, which contains about 150 known species living in tropical habitats all over the world. Preferring to live in intertidal areas, they often burrow into the sand or hide beneath rocks and coral. The shells are inhabited by a carnivorous gastropod. Some species utilize a special venom to stun their prey. Marine worms are their favored meal. While some augers are highly colored and others are dull, they all have the same characteristic flat spiral and tapering shape.

Size

Most of the augers in North America are 2 inches or smaller in length. Those found in Japan, Australia and New Zealand, known as the Marlin Spike, can grow up to 8 inches. Terebra shells from the Indo-Pacific region can be very small, or grow up to 4 inches in length. Shell thickness varies from species to species; some are very thin and brittle, while others have a heavy, thick shell. Shell circumference also varies, growing from a pin-point tip out to a wide range of maximum circumferences.

Shell Structure

All augers share the same characteristic whorl pattern. The spirals are generally flat, or lightly textured, and they are completely regular and proportional throughout the shell. The whorls get larger as they reach the top of the shell, where they finally open into an aperture at the upper end. The outer lip of the aperture is usually thin and sharp, although many specimens have been exposed to the elements, and this area may be chipped or worn. The inside edge of the aperture holds a siphonal canal which looks like a gutter.

Color

Color varies wildly depending on where the auger is found. In southern Florida and other tropical climes, vividly colored augers may be found. The augers may have orange and burnt umber colorings, as with the Flame auger. The Spotted auger, found in the south Pacific region, has spots of bright brown and purple on a background of creamy white. Meanwhile, the Eastern auger, found most often along the Atlantic coastline of North America, has much more muted colors: grays and soft browns, and occasionally earthy beige and creams.

Collecting Augers

There are two ways to collect augers: find them yourself or purchase them. Even the tropical augers are fairly inexpensive, and available at any number of online stores. An 8-inch Marlin Spike costs less than $4 in most markets as of 2010. Take a trip to any Mid-Atlantic, Southern Atlantic or Gulf Coast beach to find your own augers, free. In most cases, the shells have washed up onshore, long abandoned by their gastropods. They may not all be perfect specimens, but they are plentiful and fun to hunt out.

References

• "The Shell Book"; Julia Ellen Rogers; 1908
• SeaShellWorld.com: Auger Shells
• Shells-of-Aquarius.com: Auger Shells of the World
• "Peterson First Guide to Shells of North America"; Roger Tory Peterson; 1998