Pacific Wingfoot Snail

Author: Shelbie Montagnaro

Common names: Pacific Wingfoot Snail, Sea Butterfly

Scientific name: Gastropteron pacificum

Size Range: to 33mm (1.3 inches) in length

Identifying Features: The Sea Butterfly has a shell-like appearance. Its foot and swimming lobes are a yellow-ocre color and it has clusters of red-purplish dots all over its body. When viewed up close the main body appears translucent.

Habitat: You will often find young individuals of Gastropteron pacificum swimming erratically in open water using a flapping motion of their lateral foot lobes. They can be found from the surface of the water to as deep as 30 meters below sea level from Alaska all the way along the western coast to San Diego, California.  Despite the pelagic nature of the young of this species it lives mostly a benthic life.  It moves about on the sea floor in soft sediment and looks much like a regular snail with its lobes folded over its body.

Prey: Plankton is the only known prey of the sea butterfly, although there is research being done to find other food sources of this species.

Predators: The only known predator that has been recorded is the Cephalaspidian mollusk Navanax.  Contact with predators can induce G. pacificum to begin swimming away using its lateral foot lobes.

Pacific Wingfoot Snail at Victoria High School:  A Pacific Wingfoot Snail was collected in open water in Cadboro Bay in a plankton tow in October of 2011.  It was kept in our Seaquaria in the classroom for 5 months.  During this time it was rarely observed swimming though it did swim on occasion when it was disturbed.  It was not directly observed feeding but may have fed upon frozen brine shrimp used to feed the other aquarium inhabitants.

Video by Shelbie Montagnaro and D. Young

Photos by D. Young


Adams, J. (February 11th, 2010). Angels in the Plankton. Sea Life. Retrieved from

Pechenik, A. J. (2005). Biology of the Invertebrates: Fifth Edition. New York: McGraw-Hill

Rudman, W.B., 2001 (February 18) Gastropteron pacificum Bergh, 1894. [In] Sea Slug Forum. Australian Museum, Sydney. Retrieved from

(June 6th, 2011). Habitat. Gastropteron. Retrieved from

Wrobel, D. and Mills, C. (1998). Pacific Coast Pelagic Invertebrates: A Guide to the Common Gelatinous Animals. Monterey: Monterey Bay Aquarium.

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