large dorid (up to 8 cm)
nudibranch. Anus is on the midline about 1/4 from the
and is surrounded by 6 gills which are fully retractible.
pale gray (photo) but
may be yellow or white.
Its characteristic blackish-brown rings which are up to 1.5 cm diameter
make it easy to recognize. Dorsal surface is firm, spicules
feel gritty. Kozloff (1996) key says the rings usually are
by a white ring but I have not often seen that.
How to Distinguish from
Similar Species: The
large dark rings make this dorid easy to distinguish. However, it is
similar to another species, Discodoris
heathi, which has spots instead of rings.
In my observations,
spots seem to grade into rings.
Geographical Range: Alaska
south to Puerto
Depth Range: Low
intertidal and subtidal
to 35 m. Mostly intertidal in the north, subtidal in the
intertidal, surge channels
Feeds on Halichondria,
and Petrosia sponges. The egg ribbon is
narrow, white, attached
in an oval spiral under rock ledges by one margin.
According to Baltzley
et al., (2011),
many gastropods, including this species, have a special network of
pedal ganglia in their foot which assists in crawling. The
neurons involved produce pedal peptides which elicit an increase in the
rate of beating of cilia on the foot, resulting in crawling.
and Carlton, 1975
et al., 1980
Michael J., Allison Serman, Shaun D. Cain, and Kenneth J. Lohmann, 2011.
Conservation of a Tritonia
pedal peptides network in gastropods. Invertebrate Biology
130: 4 pp. 313-324
General Notes and
Observations: Locations, abundances,
This species is sometimes cream or even yellow. Photo by Dave
Cowles, Balboa Island, May 1999
This individual, from 10 m depth near Northwest Island, WA, is the
color pattern I more typically see. Photo by Dave Cowles,
A pair at Cape Flattery. Photo by Dave Cowles
Authors and Editors of Page:
Dave Cowles (2005): Created original page