This nudibranch has white
longitudinal ridges on a brownish background. It has a white
line outlining the edge of the dorsum. Its anus is on the
of the body, on a papilla in a groove between the dorsum and the foot (photo).
The gills are also located in this groove. It has no dorsal
except for the rhinophores. The rhinophores have longitudinal
in the clavus and project anteriorly out of a notch at the front of the
Length to 7 cm.
Armina californica (Cooper, 1863)
Common name(s): California armina
|Armina californica, 6.5 cm long,
from 6m depth in Burrows Bay.
Photo taken at Shannon Point Marine Station
|(Photo by: Dave Cowles
How to Distinguish from
This species is very distinctive. No other local species has
combination of the anus on the right side, longitudinal white ridges on
the dorsum, and no cerata.
Gulf of Alaska
Mostly subtidal, 1 to
eats sea pens such as Ptilosarcus
gurneyi. (or on sea pansies such as Renilla
south where those grow). May be largely buried in the sand
the rhinophores projecting above the surface of the sand.
laid in a pale pinkish-brown spiral chain of capsules.
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
and Nybakken, 1980
et al., 1980
et al., 1985
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 has a deep groove along the sides between the wide flap
of the dorsum and the wide flap of the foot. Here the groove
left side can be clearly seen as the animal turns.
This species has its anus on a prominent papilla on the right side,
in a groove between the flaps of the dorsum and the foot. The
above shows the groove on the right side of the animal, with the anus
the left (posterior) and the gonopore to the right (anterior)
species can crawl upside-down along the surface film of the water, as
shown by this individual crawling along the surface film of
one of our seawater tanks, about 20 cm above another individual
crawling along the bottom. Photo by Dave Cowles, August 2015
This Armina (above) is feeding on a Ptilosarcus gurneyi sea pen. Below are the remains of Ptilosarcus after active feeding by Armina. The central shaft is the rachis.
Authors and Editors of Page:
Dave Cowles (2006): Created original page