Flabellina trophina

Photo courtesy of Ken Ashman
of California Digital Diving

Flabellina trophina (Bergh, 1894)

Flabellina trophina (Bergh, 1894) In the north eastern Pacific (Port Valdez, Alaska to Seal Rocks State Beach, Oregon) (see the new Eastern Pacific Nudibranchs ) there are two species of Flabellina that are often confused for one another. Shown here is Flabellina trophina (previously Flabellina fusca). The species it is often confused with is Flabellina verrucosa (Bill Rudman's Sea Slug Forum).

Both have reddish-brown ceratal cores. Thatís where the similarity ends however. F. trophina has finely annulate rhinophores, the cerata are in a continuous line and the head has a long pointed snout. F. verrucosa on the other hand has smooth or verrucose rhinophores (hence its name), its cerata are in clusters and its head is round.

It was originally though that Flabellina trophina fed on the tube worm, Spiochaetopterus , because that is where this species was frequently found. Closer observation indicated that this aeolid is not feeding on the tube worm, but rather the small hydroids that cover the tubes.

Jackie Hildering and Glen Miller have also documented that this species also lays its eggs. Depositing oneís eggs on oneís food source is common among nudibranch and is a great way to locate them when diving. An egg mass suggests that the party who laid it is not far away.

Dave Behrens
Gig Harbor, Washington
Dec., 2005

Puerto Vallarta, Mexico
March 2005

Ali Hermosillo and Dave Behrens

Author: Pacific Coast Nudibranchs and Nudibranch Behavior
Co-Author Coral Reef Animals of the Indo Pacific
Proprietor of Sea Challengers Natural History Books

Send Dave mail at dave@seachallengers.com

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