Superfamily Dendronotoidea
Superfamily Arminoidea

Nudibranchs and other Sea Slugs

Order Nudibranchia - Suborder Cladobranchia

Superfamilies Aeolidioidea, Arminoidea & Dendronotoidea










Home > Northwest Shells & Marine Life > PNW Shells & Marine Life Photos > Nudibranchs, Sea Slugs > Nudibranchia - Aeolidioidea,
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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
Aeolidia loui Aeolidia loui Aeolidia loui
                     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).


 

Aeolidia papillosa Aeolidia papillosa Aeolidia papillosa
        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.   

Tethydidae  
Melibe leonina Melibe leoninaboth are Birch Bay State Park, WA, intertidal






 














Cerberilla mosslandica
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.




Dendronotidae
Dendronotus albopunctatus
Waldron Island, WA, subtidal









Arminidae
Armina californica Armina californica           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.

Dendronotus dalli
San Juan Islands, WA, subtidal

Dendronotus albus Dendronotus albus Dendronotus albus Dendronotus albus 
           Friday Harbor, WA, subtidal                Freshwater Bay, WA, subtidal      Frehswater Bay, subtidal   Freshwater Bay, subtidal
                                                                                                                                                                         laying eggs




Dendronotus subramosus Dendronotus subramosus Dendronotus subramosus Dendronotus subramosus
              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.






Dendronotus robilliardi Dendronotus robilliardi
                                   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.   












Dendronotus venustus Dendronotus venustus Dendronotus venustus
Marrowstone Point, WA      Neptune State Park, OR, intertidal                   Rich Passage, WA, subtidal
             intertidal
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.
Dendronotus iris Dendronotus iris Dendronotus iris
 Barkley Sound, BC, subtidal, with eggs         Whidbey Island, WA, subtidal                          Monterey, CA, subtidal









Hermissenda crassicornis & opalescens
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
Doto cf amyra Doto amyra
              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.





































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Melibe leonina Melibe leonina
Barkley Sound, BC, subtidal     Chemainus, BC, subtidal, with eggs


Doto columbiana
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)  








This page last revised: 10-12-2022





















Dendronotus iris Dendronotus iris
        Point Whitehorn Park, WA, intertidal              Maple Bay, BC, subtidal, eggs  








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)


































Doto kya Doto kya
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













Myrrhinidae
Hermissenda crassicornis Hermissenda crassicornis Hermissenda crassicornis
             Freshwater Bay, WA, subtidal                       Birch Bay State Park, WA, intertidal                Barkley Sound, BC, subtidal




































Hermissenda crassicornis
LaPush, WA, intertidal

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)








Hermissenda opalescens
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
Flabellinopsis iodinea Flabellinopsis iodinea
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)  





































 












Dendronotus rufus Dendronotus rufus
       Friday Harbor, WA, subtidal                  Whidbey Island, WA, subtidal