Nudibranchs,SeaSlugs-Nudibranchia-Cladobranchia-1

Click on photo to enlarge. Scale line in photo equals 1cm unless otherwise specified.
* Species which are the most commonly encountered nudibranchs on the beach.

Those in the order Nudibranchia are the true nudibranchs. The adult forms have a complete
absence of a shell and have externally exposed respiratory organs.

Superfamily Aeolidioidea

Aeolidiidae

Port Hardy, BC, intertidal Rich Passage, WA, subtidal Seattle, WA, subtidal
close-up of warty rhinophores

Aeolidia loui Kienberger, Carmona, Pola, Padula, Gosliner & Cervera, 2016
Shaggy Mouse or Shag-Rug Nudibranch
intertidal to subtidal north Mexico to central BC size to 100mm
This species was recently separated from A. papillosa. It overlaps in range and habitat. The body color is variable from white to pinkish-grayish-green to orange or brown. It's general appearance is very similar to A. papillosa. However, it's rhinophores are covered with distinct, wart-like tubercles (see arrow on right photo).

Birch Bay State Park, WA, intertidal Rich Passage, WA, subtidal Illahee State Park, WA, subtidal
wrinkled/speckled rhinophores

Aeolidia papillosa (Linnaeus, 1761)
Shaggy Mouse or Shag-Rug Nudibranch *
intertidal to 900m southern California to at least north Vancouver Island, BC size to 127mm
This species is occasionally seen intertidally. The body and cerata color may be variable - white to beige to dark brown with dark flecks. The cerata are somewhat flattened and broader at the base than the tip. The rhinophores often have a mottled appearance and may have slight wrinkles giving the illusion of warts. Close inspection is needed while the specimen is submerged so all the appendages are extended.

Burien, WA, subtidal
Cerberilla mosslandica
McDonald and Nybakken, 1975
Moss Landing Aeolid
subtidal size to 9mm
southern California to southern BC
This species burrows in soft sediments.

Arminidae

Shilshoe Bay, WA, subtidal Alki Point, WA, subtidal eating sea pens

Armina californica (Cooper, 1963)
Striped Nudibranch
intertidal to 230m on sandy bottoms Panama to northern Alaska size to 7cm
This species is infrequently found intertidally in the northwest. It has a distinct look and can't be confused with any other species.
(synonyms - Armina columbiana, Armina vancouverensis, Pleurophyllidia californica)

Dendronotus dalli Bergh, 1879
Dall's Dendronotus
subtidal size to 14cm
northern Washington to northern Alaska
The body is white to pink and the cerata
are tipped in white.
(previous name - Dendronotus elegans)

Dendronotus albopunctatus Robilliard, 1972
White-spotted Dendronotus
subtidal size to 60mm
southern Oregon to northern BC
This species has a wide foot for its body. There are white
spots over a body which is pink to reddish brown.

Rich Passage, WA, subtidal Rich Passage, WA, subtidal Neptune State Park, OR, intertidal

Dendronotus subramosus MacFarland, 1966
Stubby Dendronotus
intertidal to 120m northern Mexico to southern BC size to 33mm
This species is rarely found intertidally and can be difficult to find in the subtidal. Its color is variable and may be speckled yellow to brown, orange, green or white. Four light brown lines run down the length of its body starting at the base of the rhinophores.

Anacortes, WA, in an aquarium Rich Passage, WA, subtidal

Dendronotus robilliardi Korshunova, Sanamyan, Zimina, Fletcher & Martynov, 2016
Robilliard's Dendronotid
intertidal to 30m Puget Sound WA to Alaska to west Russia size to 35mm
Rarely seen intertidally in our area. Looks similar to D. albus but has a white line on the back of the rhinophore sheath and the dorsal appendages are moderately branched. The central appendages may have orangish bands.

Dendronotus albus MacFarland, 1966
White Dendronotus
intertidal to 30m northern Mexico to central Alaska size to 35mm
This is infrequently seen intertidally. It has a white body and the cerata are tipped with opaque white, orange, red or brown. A white line extends down the back to the tip of the tail. A recent DNA study determined that Dendronotus diversicolor is not a unique species and is now considered to be Dendronotus albus. This is also evident by the mating pair of the two color forms shown in our second photo.

Marrowstone Point, WA Neptune State Park, OR, intertidal Rich Passage, WA, subtidal Freshwater Bay, WA
intertidal subtidal

Dendronotus venustus MacFarland, 1966
Branched Dendronotus
intertidal to 400m northern Mexico to Alaska size to 10cm
This species can occasionally be found intertidally. It is usually gray to brown in color with
mottling of yellow, green or brown. The projections are stoutly branched. This species was recently separated from the Atlantic species D. frondosus. More study needs to be done to determine the full range of D. venustus.

Strawberry Hill, OR, intertidal
Hermissenda crassicornis & opalescens
These species co-exist at least as far north as central Oregon. At this location H. crassicornis typically far outnumber the quantity of H. opalescens observed.

Dendronotus rufus O'Donoghue, 1921
Red Dendronotus
subtidal size to 28cm
central Washington to southern Alaska
The projections on the body are all
tipped with red to magenta as well as
edging the foot. The body is white.

Dotidae

Turn Island, WA, subtidal Rich Passage, WA, subtidal, with eggs

Doto amyra Marcus, 1961
Orange Doto
intertidal to subtidal size to 25mm
northern Mexico to southernmost Alaska
Rare to find intertidally, this species is still under study and may turn out to be more than one species. The body is translucent white. The bulbous cerata may be yellow to orange.

Rich Passage, WA, subtidal, with eggs
Doto columbiana O'Donoghue, 1921
intertidal to 60m size to 12mm
southern California to northern BC
This species can be difficult to find, hidden among sea fir hydroids. It is whitish to yellowish gray with varying amounts of brown patches. The cerata have 4-5 rings of flat tubercles

Melibe leonina (Gould, 1852)
Lion's Melibe
intertidal to 37m size to 17.5cm
northern Mexico to central Alaska
This is infrequently found intertidally, but when it is it can often be in very large numbers. It takes a sharp eye to spot this semi-transparent species in a tide pool among eelgrass or seaweed.
(previous name - Chioraera leonina)

Dendronotus iris Cooper, 1863
Rainbow Dendronotus
subtidal to 215m size to 30cm
northern Mexico to northern Alaska
This species can exhibit a variety of colors. The gill tufts will be the same color as the body. It has a white line along the rim of the foot.
The last photo shown are the eggs surrounding the tube anemone which is this species' favorite food.
(synonym - Dendronotus giganteus)

both Freshwater Bay, subtidal
Doto kya Marcus, 1961
intertidal to subtidal size to 10mm
north Mexico to south BC
This species is yellowish white with brown blotches. It looks very much like the D. columbiana except this one lacks the dark rings on its rounded ceratal tubercles. They are very difficult to tell apart

Hermissenda crassicornis (Eschscholtz, 1831)
Opalescent Nudibranch *
intertidal to 37m northern California to central Alaska size to 80mm
This species is often found intertidally. It has a distinctive bright orange stripe on its head. The center of the cerata may appear pale orange to dark brown and are usually tipped in white and orange. There is a white stripe down each cerata which is a distinguishing feature of this species. In specimens with very dark cerata, this line can be somewhat obscured.
(previous names - Phidiana crassicornis, Cavolina crassicornis)

Strawberry Hill, OR, intertidal
Hermissenda opalescens (J.G. Cooper, 1863)
Opalescent Nudibranch
intertidal to at least 20m northern Mexico to Oregon size to at least 50mm
This species was recently reinstated as a separate species from H. crassicornis. It also has the bright orange stripe on its head and orange to brown cerata. But this species does not have the white stripe along the cerata.
(previous name - Aeolis opalescens)

Flabellinopsidae

both - Neah Bay, WA, subtidal
Flabellinopsis iodinea (Cooper, 1862)
Spanish Shawl
intertidal to 140m size to 60mm
northern Mexico to Vancouver Is. BC; Ecuador; Galapagos
This colorful species is rarely seen in WA and BC. It seems to arrive only during extremely warm summers. It is hard to mistake the purple body and bright orange cerata with any other species.
(previous name - Flabellina iodinea, Coryphella iodinea)

Nudibranchs and other Sea Slugs

Order Nudibranchia - Suborder Cladobranchia

Superfamilies Aeolidioidea, Arminoidea & Dendronotoidea