How to Distinguish from Similar Species: Look carefully for the small folds on the columella as well as the outer lip of the aperture in order to key this species to the right family. Amphissa versicolor grows to only 1.5 cm and the axial ribs are angled instead of aligned with the length of the shell and it may have a pattern of light and dark markings. Amphissa reticulata, a rare subtidal species, has the middle third of the outer lip of the aperture rounded and also only gets to 1.5 cm long. In several other members of Family Columbellidae the spiral ridges are found only on the anterior portion of the body whorl.
Geographical Range: Kodiak Island, Alaska to San Pedro, California. Common in the Puget Sound area and the outer Northwest coast. In California A. versicolor is more common.
Depth Range: Intertidal to 29 m (But the individual above was trawled from a depth of 120 m in San Juan Channel).
Habitat: Rocky to muddy beaches and subtidally.
Biology/Natural History: This species is mainly a scavenger on dead flesh and dead algae, which it uses its long siphon to find. May be found in Enteroctopus dofleini middens consuming the scraps left from discarded octopus meals. It is a very active snail. Kent (1981) found that it turns and flees rapidly when it encounters the seastars Pisaster ochraceus or Leptasterias hexactis. If several tube feet have attached to the shell, the snail dislodges the tube feet with its proboscis. When moving, a single muscular wave moves along the snail's foot from front to back. They climb well, and often rear up on the back of the foot to feel for new substrate. A gland on the rear of the foot secretes a thick mucus strand which the animal can use to suspend itself in the water. Females attach vase-shaped capsules to rocks. Each capsule contains about 60 white eggs. The empty shells are often used by hermit crabs.
a study on San Juan Island, Pernet (2007) found that different
individuals of this species matured at very different sizes.
Immature individuals were characterized by shells in which
outer aperture was thin and easily broken. These individuals
still growing. Mature individuals had outer apertures which
much thicker, and were growing little or not at all even if they were
not as large as some other immature individuals which were still
growing. Pernet concluded that this species has determinate
growth. Exposure in the lab to effluent from Cancer productus
did not affect the shell form or thickness, suggesting that the large
range of sizes at maturity is not due to a response to predation by the
Flora and Fairbanks, 1966
Kozloff 1987, 1996
Smith and Carlton, 1975
Kent, Bretton W., 1981. Behavior of the gastropod Amphissa columbiana. Veliger 23: 275-276
Pernet, Bruno, 2007.
Determinate growth and variable size at maturity in the
marine gastropod Amphissa
columbiana. American Malacological Bulletin 22:
General Notes and Observations: Locations, abundances, unusual behaviors:
I do not find these often near Rosario but they are more common in deep trawls here and on the outer coast.
Authors and Editors of Page:
Dave Cowles (2007): Created original page
Jonathan Cowles (2007): Updated page with CSS