Archidoris montereyensis (Cooper, 1862)

Common name(s): (False) sea lemon, Monterey dorid, Monterey sea-lemon

Synonyms:
Phylum Mollusca
 Class Gastropoda
   Subclass Opisthobranchia
    Order Nudibranchia
      Suborder Doridacea
       Family Archidorididae
Archidoris montereyensis from Sares Head.  Approx length 8 cm
(Photo by: Dave Cowles July 2000)
Description:  This large dorid nudibranch has an anus on the dorsal midline about 1/4 the length from the posterior end.   The seven gills can be completely retracted.  The perfoliate rhinophores are stout at the base and taper from base to tip.  The dorsum has prominent tubercles.  The animal's color is lemon yellow (sometimes quite light--photo), with darker rhinophores and gills (photo).  Black spots on the dorsum are on and between tubercles.  The number of spots per individual seems to vary quite a lot, and some have only a few spots (photo).

How to Distinguish from Similar Species: The sea lemon Anisodoris nobilis has spots only between the tubercles, and the rhinophores and gills are lighter than the rest of the dorsum.  This species does not smell and produces little mucus, while Anisodoris nobilis may give off lots of sweet-smelling mucus when disturbed.  This species' congener, Archidoris odhneri, does not have the dark spots on the dorsum

Geographical Range: Kachemak Bay, Alaska to San Diego, CA

Depth Range: Intertidal to 50 m.  Common intertidally in north end of range, subtidal at south end.

Habitat: Rocky areas and pilings, open coast and protected waters.

Biology/Natural History: Feeds on yellow crumb-of-bread sponge Halichondria panicea, as well as other sponges.  Animals are simultaneous hermaphrodites, lay eggs throughout the year.  Non-motile sperm from partner is stored in a seminal receptacle for some time before the sperm become motile and fertilize the eggs as they are laid.  Eggs are in capsules of several eggs each, which are then formed into a narrow cord which is folded into a bright yellow or cream gelatinous ribbon of about 2 million eggs.  The ribbon is attached in a coil by one edge to a hard substrate.  Egg masses exposed to the light have higher mortality rates.  Eggs hatch in 20-25 days, trochophore larvae settle within about 2 hours of hatching.

Sponges which live on the motile scallop Chlamys hastata are less vulnerable to predation by this nudibranch.

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 two main neurons involved produce pedal peptides which elicit an increase in the rate of beating of cilia on the foot, resulting in crawling.



 
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References:

Dichotomous Keys:
Kozloff 1987, 1996
Smith and Carlton, 1975

General References:
Behrens, 1991
Kozloff, 1993
Morris et al., 1980
O'Clair and O'Clair, 1998
 

Scientific Articles:

Baltzley, 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

Bloom, S., 1975.  The motile escape response of a sessile prey:  a sponge-scallop mutualism.  J. Exp. Mar. Biol. Ecol. 17: 311-321



General Notes and Observations:  Locations, abundances, unusual behaviors:

These nudibranchs are quite common around Rosario, and also on the open coast of Washington.


This individual, found in a sea cave at Cape Flattery, appears to have just finished laying eggs.  Note the second individual nearby.  Nudibranchs are usually hermaphrodites but fertilize one another.
There were several aggregations of 2-5 individuals of this species on the rocks in this cave.  Photo by Dave Cowles, July 2008
 
 
Light color
This 7-cm individual is quite light in color and has only a few black spots, but nevertheless keys to this species.  Found subtidally at Sares Head.


Closeup views of the rhinophores and gills of the light-colored individual above.  Note the scattered dark spots which can be found both on and between the tubercles, and the fact that the light yellow coloration can be clearly seen when up close.
Rhinophore Gill



Authors and Editors of Page:
Dave Cowles (2005):  Created original page