How to Identify Chitons

Chitons are specialized molluscs that resemble limpets but they have segmented shells and other qualities that make them stand out from other molluscs.

Difficulty: Moderate

Instructions

1. Know the habitat of chitons. Chitons live mainly along rocky shorelines, and you'll find them attached to rocks in the tidal zone.

2. Observe the size of a chiton. Most chitons are between 2 and 8 centimeters long. However, chitons can grow to be very large, up to 30 centimeters in length.

3. Note the features of a chiton. They have an oval shape, a fleshy girdle that is typically textured and a series of overlapping shell segments on the top of the body.

4. Learn about the shell of the chiton that always had eight segments. The first and last segments are usually half-circle shaped. The other six segments are "V" shaped or rectangular shaped. These segments fit together with interlocking teeth and grooves.

5. Find and use a guidebook to seashells to help you better identify the different characteristics of the many species of chitons. A good guidebook to use is "A Guide to Field Identification: Seashells of North America" published by Golden Press.

Tips & Warnings

• You are more likely to find a living chiton than a shell washed up on the beach because chiton shells tend to fall apart easily.
• The girdle of a chiton is a fleshy extension of the mantle that all chitons have.
• A few species of chitons have shells underneath their girdle so the shells are not visible. An example of this type of chiton would be the Giant Pacific Chiton.
• When collecting chitons, preserve the entire animal for identification purposes. The girdle is very useful in identifying the species of chiton.

Resources

• A Guide to Field Identification: Seashells of North America.