Phylliroe bucephala

Photo taken by Orso Angulo Campillo

Phylliroe bucephala Péron & Lesueur,1810

On many occasions, we are amazed by the strange sightings of wonderful slugs, some of which , have only been seen two or three times since the original description. But besides the strange opportunity that some of them give us to see them, others almost always avoid us and deprive us of their wonderful colors and strange forms.

This is the case of the pelagic dendronotid nudibranch Phylliroe bucephala, which lives in open waters and feeds on small planktonic organisms. This little slug can only been seen in plankton trawling if you are lucky, because most of the time they are destroyed due to their soft body.

Last May, I had the opportunity to witness a planktonic bloom in Bay of Dreams (formerly Ensenada de Muertos), where a huge amount of tiny pelagic soft body animals were washed ashore. While trying to grab some jelly fishes (medusae) and avoiding to be stung by some of them, I saw this little flat thing floating and moving, and to my surprise it was a P. bucephala. The presence of P. bucephala was kind of foggy, due to the rarity of the sightings, it was only known as "circumtropical" (Bertsch, 1979), just until 1996, when Fernandez-Alama looked into collections of the planktonic trawlings made in the Sea of Cortez by the Instituto Politecnico Nacional, she was able to confirm its presence. With this encounter, I am able to remember to keep my eyes open, because you never know when the next slug will appear.

Orso Angulo Campillo
La Paz, Baja California
Jul., 2002

Bertsch, H. 1979 Tropical faunal affinities of opisthobranchs from the panamic province (eastern Pacific). The Nautilus 93(2-3):57-61.

Fernandéz-Alama, Ma. 1996. New records of Phylliroe (Opisthobranchia:Nudibranchia) from the Gulf of California, México. The Veliger 39(4):356-359, figs.1-2.

Gasca, R.; Suarez Morales, E. 1994. An Illustrated Record of Phylliroe bucephala Peron and Lesueur (Gastropoda: Nudibranchia) in the Gulf of Mexico. Investigaciones Marinas CICIMAR9(2):109-111.

Webmaster's Note: This is a very insteresting beast indeed. According to Bill Rudman's Sea Slug Forum , Phylliroe is one of the few nudibranchs to exhibit bioluminescence. So like Orso says, keep your eyes peeled, that strange glow you see in the water may turn out to be one of our friends!

San Diego, CA
Jul., 2002

Orso and Liza, La Paz, Baja California Sur

I have a degree in Marine Biology and currently doing my last semester of the Master´s degree. Liza and I are currently located in La Paz, Baja California Sur, were I do my work in Sea Slugs. My main interest is the taxonomy of the group, due to the wonderful specimens that crawl around here, but also some aspects of their ecology.

For the past 2 years we have been monitoring the fluctuations of the populations of Opisthobranchs around La Paz (which is my Master´s project).

Also I have been experimenting with digital photography, I have a Coolpix 995 and also a traditional Nikon N90, where I used both to have in paper or slide and digital (to avoid scanning).

You can drop Orso a note at

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