Nudibranchs,SeasSlugs-Nudibranchia-Cladobranchia-2

Abronica abronia (MacFarland, 1966)
Graceful Aeolid
intertidal size to 15mm
northern Mexico to northern Washington
This species is primarily intertidal but rare to see. It has a purple band in the middle of the rhinophores. Its multicolored cerata are tipped in yellow, greenish to brown in the middle and yellow to red at the base.
(previous names - Cuthona abronia, Trinchesia abronia)

Cuthonellidae

Bob Creek, OR, intertidal Otter Crest, OR, intertidal

Cuthonella cocoachroma (Williams & Gosliner, 1979)
Chocolate Aeolid
intertidal size to 20mm
central California to northern Washington
The name comes from the brown color of the cerata which may be reddish to chocolate brown. It is very similar to C. concinna.
(previous name - Cuthona cocoachroma)

Petersburg, AK, intertidal Sechelt Inlet, BC, subtidal

Coryphella verrucosa (M. Sars, 1829)
Red-gilled Nudibranch
intertidal to 300m size to 10cm
northern Washington to southern Alaska and
circumboreal, Sea of Japan and North Atlantic
This species is infrequently found intertidally.
(previous names - Flabellina verrucosa, Aeolidia verrucosa)

Coryphellidae

Maple Bay, BC, subtidal Shilshoe Bay, WA, subtidal

Coryphella trophina (Bergh, 1890)
Long-mouthed Aeolid
subtidal to 65m size to 50mm
central Oregon to southern Alaska; Sea of Japan
This species has a pronounced pointed snout and the cerata are
continuous along its back instead of in clusters.
(synonym - Flabellina trophina, Flabellina fusca, Coryphella fusca)

Neah Bay, WA, subtidal, right one with eggs
Eubranchus rustyus (Er. Marcus, 1961)
Rusty Aeolid
intertidal to at least 20m size to 25mm
northern Mexico to Ketchikan, Alaska
This little species is difficult to spot among the hydroids. The body is white with yellow-white dots and some brownish colorations. The cerata and rhinophores are tipped in white.
(previous name - Capellinia rustya)

San Juan Islands, WA, subtidal Bainbridge Island, WA, subtidal

Dirona pellucida Volodchenko, 1941
Translucent Dirona
intertidal to subtidal size to 12cm
central Oregon to northern Alaska; Sea of Japan to Russia
This is infrequently found intertidally. White speckling on the lower body distinquish it from D. albolineata.
(synonym - Dirona aurantia)

Drakes Estero, CA, intertidal
Diaphoreolis flavovulta (MacFarland, 1966)
Yellowhead Aeolid
intertidal size to 10mm
central California to northern Washington
This species is primarily intertidal but rare to see in its northern range. It has a yellowish head. The rhinophores and oral tentacles are tipped in white. There cerata are brown to green with white spots.
(previous name - Tenellia flavovulta, Cuthona flavovulta, Cratena flavovulta)

both from Seal Rock, OR, intertidal
Dirona picta MacFarland, 1905
Colorful Dirona
intertidal to size to 30mm
northern Mexico to northern Oregon; Sea of Japan
This species may be a wide range of colors. The body color ranges from pink-orange to gray-green, with splotches of white to green and pink-red spots.

Cumanotus fernaldi Thompson & Brown, 1984
Fernald's Aeolid
subtidal size to 18mm
southern California to southern BC
This species has very long cerata, as long as its body.

Drakes Estero, CA, intertidal
Diaphoreolis lagunae (O'Donoghue, 1926)
Laguna Beach Aeolid
intertidal to shallow subtidal size to 14mm
northern Mexico to southern Oregon
This species has a white body with dark cerata. The rhinophores, head and ceratal tips are yellow.
(previous names - Tenellia lagunae, Cuthona lagunae, Trinchesia lagunae, Cratena rutila)

Egmont, BC, subtidal
Cuthonella concinna (Alder & Hancock, 1843)
Neat Aeolid
subtidal size to 15mm
southern BC to northern Alaska; circumpolar
This is a very plain species
and may be cream to yellow.
(previous name - Cuthona concinna, Trinchesia concinna)

Rich Passage, WA, subtidal
Trinchesia albocrusta (MacFarland, 1996)
White-crusted Aeolid
intertidal to subtidal size to 12mm
northern Mexico to central Alaska
This species is rare to find intertidally. It is identifiable by the white encrustations on the cerata, head and rhinophores.
(previous name - Tenellia albocrusta, Cuthona albocrusta)

Trinchesiidae

Barkley Sound, BC Rich Passage, WA Strawberry Hill, OR Strawberry Hill, OR
subtidal subtidal intertidal (These 2 photos taken on same day.) intertidal

Catriona columbiana (O'Donoghue, 1922)
British Columbia Aeolid
intertidal to subtidal size to 20mm
southern California to southernmost Alaska; South Africa; New Zealand; Japan
This species is very infrequently seen intertidally. It feeds on the hydroid Tubularia. The rhinophores are orange with a white tip. The cerata are usually orange but may be brown and have a thick white stripe on the outer side.
(synonyms - Tenellia columbiana, Cuthona columbiana, Catriona alpha, Cratena spadix)

Cuthonella punicea (Millen, 1986)
Pomegranate Aeolid
subtidal northeast Vancouver Island, BC size to 20mm
The cerata are pomegranate red with white markings. It feeds on the equally red hydroid Zyzzyzus rubusidaeus which is visible in the photo.
(previous name - Cuthona punicea)

Cuthonidae

Rich Passage, WA, subtidal Neah Bay, WA, subtidal, with eggs

Cuthona divae (Marcus, 1961)
Rose-pink Cuthona
intertidal to 20m southern California to southern BC size to 34mm
This is rarely found intertidally. The first 2-3 rows of cerata begin in front of the rhinophores and are tipped in white. Its color may be cream to pink.
(previous name - Precuthona divae, Cuthona rosea)

Strawberry Hill, OR, intertidal
Zelentia fulgens (MacFarland, 1966)
Shiny Aeolid
intertidal to shallow subtidal size to 8mm
central California to northern Washington
This species has a translucent body with white specks. The cerata have a yellow band at the tip and the base with brown between.
(previous names - Tenellia fulgens, Cuthona fulgens, Cratena fulgens)

Neah Bay, WA, subtidal
Zelentia pustulata (Alder & Hancock, 1854)
Pimpled Aeolid
subtidal to at least 15m size to 20mm
southern BC to central Alaska; north Atlantic south to Maine and France
This species has a translucent white body with reddish-brown cerata speckled with white.
(previous name - Cuthona pustulata, Trinchesia pustulata, Tenellia pustulata, Eolis pustulata)

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 sea slugs. The adult forms have a complete
absence of a shell and have externally exposed respiratory organs.

Superfamily Fionoidea

Unidentiidae

Rich Passage, WA, subtidal
Pacifia amica Korshunova, Martynov, Bakken, Evertsen,
Fletcher, Mudianta, Saito, Lundin, Schrödl & Picton, 2017
Red Sparkly Aeolid
subtidal to at least 15.2m size to 15mm
This newly discovered species is known only from Rich Passage, just east of Port Orchard, WA and the Pearse Islands, BC. It was found on stones with hydroids. It is translucent white with opaque white lines on the body. The cerata are orange-red to light pink with scattered small spots. The ceratal tip is transparent. The rhinophores are smooth.

Rich Passage, WA, subtidal Blakely Rock WA, subtidal
Eubranchus sanjuanensis Roller, 1972
San Juan Aeolid
subtidal to at least 20m size to 6mm
northern Washington to southeast Alaska
This tiny species is gray-white. The cerata cores are reddish to yellow.

Apata pricei (MacFarland, 1966)
Price's Aeolid
subtidal size to 25mm
southern California to southern Alaska
The body is gray - white and a white line on the tail divides along each side of its body, extending about a third of the way up the body. The cerata are tipped with white, then a band of brown and the remainder is yellowish.
(previous name - Flabellina pricei, Coryphella pricei)

Eubranchidae

Ladysmith, BC, subtidal
Eubranchus rupium (Moller, 1842)
Rocky Aeolid or Green Balloon Aeolid
subtidal to 80m circumpolar size to 12mm
This small species has a yellowish body and frosted white cerata with green cores. White flecks cover the body.
(previous name - Eubranchus olivaceus)

Ziminella japonica (Volodchenko, 1941)
Japanese Aeolid
subtidal Circumboreal size to 75mm
This species can be easily confused for the Shaggy Mouse nudibranch. In this species the cerata start behind the rhinophores. The color is cream to pink.
(synonyms - Flabellina japonica, Flabellina salmonacea, Coryphella salmonacea)

Orienthella trilineata (O'Donoghue, 1921)
Three-lined Aeolid
intertidal to 50m size to 36mm
northern Mexico to southern Alaska
This is occasionally found intertidally. The body is white to gray and has three opaque white lines extending down the body. The cerata are orange to red and infrequently brown. They are tipped in white, yellow or orange. The rhinophores are white with the upper portion colored orange. We also see some with rhinophores which are completely white.
(previous name - Flabellina trilineata, Coryphella trilineata)

Freshwater Bay, WA, subtidal Rich Passage, WA, subtidal Bainbridge Island, WA, subtidal
laying eggs on horse clam siphon

Dirona albolineata MacFarland, 1905
Frosted Nudibranch *
intertidal to 37m size to 18cm
southern California to southern Alaska; also Japan & Siberia
It is occasionally found intertidally. The body is translucent. The cerata can be white, yellow, salmon or purplish in color.

Antiopella fusca (O'Donoghue, 1924)
White-and-Orange Tipped Nudibranch

intertidal to 30m size to 25mm
southern California to southern Alaska; Sea of Japan
This is occasionally found intertidally. It is easily identified by the orange and white tipped cerata.
(synonym - Janolus fuscus)

Janolus gelidus Millen, 2016
subtidal, 17-37m southern BC to northern WA size to 23mm
The body color on this species is translucent very pale to medium orange. The rhinophores and papillae have white tips. They seem to prefer silty sand and mud bottom. It is most likely to be confused with Dirona pellucida.

Tritoniidae

San Juan Islands, WA, subtidal Neah Bay, WA, subtidal

Tochuina gigantea (Bergh, 1904)
Orange-Peel Nudibranch
subtidal to 363m size to 50cm
southern California to northern Alaska, Siberia
This species gets very large. The body is orange-yellow with a yellow to pink foot. A white band rims the body. This species was separated from Tochuina tetraquetra.
(previous names - Tritonia tetraquetra sensu Bergh, 1879, Limax tetraquetra, Tritonia gigantea)

Friday Harbor, WA, subtidal Cape Arago, OR, intertidal
Tritonia festiva (Stearns, 1873)
Festive Tritonid or Diamondback Nudibranch
intertidal to 50m size to 10cm
northern Mexico to southern Alaska; Japan
This is infrequently seen intertidally. It may be white to yellow to brownish. The back is patterned with white lines.
(previous name - Lateribranchiaea festiva)

Dash Point State Park, WA, subtidal Orcas Island, WA, subtidal
Tritonia exsulans Bergh, 1894
Pink Tritonia
intertidal to 656m southern California to northern Alaska size to 22cm

This species is infrequently seen intertidally. It is pink to reddish-salmon. A white band lines the foot and the lateral side between the appendages. It likes sandy bottoms and feeds on sea pens and sea whips. This was recently separated from Tritonia tetraquetra, which does not have the lateral white lines between the appendages. T. exsulans is more common subtidally in the Pacific Northwest. T. tetraquetra is infrequently seen and is more common in colder northern waters. T. tetraquetra is also trans-Pacific.

Nudibranchs and other Sea Slugs

Order Nudibranchia - Suborder Cladobranchia

Superfamilies Fionoidea, Proctonotoidea & Tritonioidea