Berthella californica (Dall, 1900)
Common name(s): California berthella, White berthella
|Synonyms: Pleurobranchus californica, Pleurobranchus denticulatus|
|Berthella californica from Coffin Rocks, WA. Length about 2.5 cm (Scale in background is mm).|
|(Photo by: Dave Cowles,July 2005)|
How to Distinguish from Similar Species: No other nudibranch-like animal in this area is white, with a lateral sheetlike extension above the foot and only one gill on the right side. Several dorid nudibranchs such as Archidoris odhneri look superficially similar but they have no lateral flap and their gills are a circle on the dorsum. Tylodina fungina is another Notaspidean, found in southern CA, but it is bright yellow.
Geographical Range: Point Craven, Alaska to Coronados Island, Baja California
Biology/Natural History: This uncommon but striking species apparently preys on ascidians and perhaps on sponges. Little is known about this species. Some members of this family can repel predators with extremely strong acid secretions from glands in the dorsum.
LaForge and Page studied B. californica development. The
species lays its eggs in a coiled ribbon attached to the substrate along
one edge. The egg ribbon is white, about 1 cm wide, and 1 mm thick.
The egg capsules in the ribbon are oval, around 1.6 or 1.7 mm wide, and
contain 1-2 eggs each. At 11-12 C the eggs hatched as veliger larvae
in 19 days. Its developmental pattern resembles that of nudibranchs
more closely than does that of other pleurobranchoideans which have been
studied. They also discovered that the snail-like shell which the
larva has only becomes bilaterally symmetrical late in development.
Some of the events that occurred when the larva settled and metamorphosed
into the adult form included a rapid expansion of the mantle over the shell
so that the shell became internal. They also lost the large larval
velar lobes and began growing the rhinophore and oral veil. The larva
also appeared to have an ospradium (chemosensory organ), though the adult
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Morris et al., 1980
LaForge, Nicole L. and Louise R. Page, 2007. Development of Berthella californica (Gastropoda: Opisthobranchia) with comparative observations on phylogenetically relevant characters among nudipleuran opisthobranchs. Invertebrate Biology 126(4): 318-334
We have not often seen this animal around Rosario.
In this view of the right side, one can see the gill (and the gonopore in front of it?) Photo by Dave Cowles, July 2005
In this view the rolled rhinophores can readily be seen. Photo by Dave Cowles, July 2005
An underwater photo by Kirt Onthank, July 2007