Overview

Key Features:

Large size and burgundy color.

Primary Common Name:

Gumboot chiton

General Grouping:

Snails, limpets, abalone, chitons

Geographic Range:

Alaska to southern California

Aleutian Islands in Alaska to the southern Channel Islands, California

Intertidal Height:

-1 to -2 feet (-0.3048 to -0.6096 meters)

Notes:

Low intertidal, in tide pools and surge channels.

Subtidal Depth Range:

Minimum Depth: 0 meters or 0 feet
Maximum Depth: 20 meters or feet

Notes:

Maximum depth not found, but at least to 20 m.

Habitats:

bay (rocky shore), exposed rocky shore, kelp forest, protected rocky shore

Notes:

Rare in the low intertidal, but relatively common in kelp forests. Found both on the rocky reef as well as adjacent sandy areas.

Abundance:

Relative Abundance:

Uncommon

Species Description:

General:

This is the largest chiton in the world and is a monospecific genus (i.e. there are no other Cryptochiton species.). All chitons have eight calcareous plates (or shells), but the mantle of this species completely covers the plates in a burgundy red sheath covered with small bumps (fascicles). Adults tend to be uniform in color, although they can have green algal or other growths on the mantle. The foot is a lighter golden-yellow, and the ventral surface of the mantel is a pale orange-red, often mottled. The mantle of juveniles can be very splotchy, with large light purple patches mixed in with the red.

Distinctive Features:

Large size, burgundy color and ability to roll into a sphere if disturbed. This species looks like a rugby ball cut lengthwise but with the coloring of a football.

Size:

Length: up to 33 cm

Natural History:

General:

Chitons are an odd kind of mollusk, with eight overlapping plates replacing a single shell. Like other mollusks, they have a powerful foot to firmly grip the rocky substratum. They are very slow moving, and graze the rocks, scraping off algal films or feeding directly on larger algae.

Females lay spiral strings of eggs that re up to 1 m long and a reddish color. These strings are quickly broken by wave action and surge, but this stimulates males to release sperm into the water column. Five days after fertilization, a free-swimming larval stage remains in the water for less than one day, then settles out and develops into a juvenile.

Individuals remain in the same area for multiple years, and may live up to 20 years.

Predator(s):

Predators of juveniles include fishes and sea stars. Adults are parasitized by various snails, most of which rasp into the tissue and consume body fluids.

Prey:

Algal film and algae.

Feeding Behavior:

Herbivore

Notes:

Chitons have a radula and use it to rasp the surface of rocks or algae, scraping off tissue layers. Adults feed mostly on red algae, including Chondracanthus, Mazzaella and Plocamium, but also drift kelp.

Seasonal Behavior

March - May

Reproduction:

Spawning can last up to one week and individuals may lose up to 5 percent of their body weight.

Issues

Monterey Bay National Marine Sanctuary:

None known.

References

• Carlton, J.T. 2007.
  The Light and Smith Manual, 4th edition
  Intertidal Invertebrates from Central California to Oregon
  University of California Press. 1001 p.
  
• Lamb, A. and B. P. Hanby. 2005. Marine life of the Pacific Northwest. Harbour Publishing. 398 p.
• Morris, R.H., D.P Abbott, and E.C. Haderlie. 1980. Intertidal Invertebrates of California. Stanford University Press, Stanford, California. 690 p.

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