Flabellina vansyoci

Photo courtesy of Dave Behrens

Flabellina vansyoci Gosliner, 1994

This colorful aeolid from the southern portion of the Pacific Coast of North and Central America has been described by Terry Gosliner (Gosliner, 1994), and given the name Flabellina vansyoci, in recognition of friend and colleague, California Academy of Sciences biologist Robert Van Syoc.

In Pacific Coast Nudibranchs (Behrens 1991) I referred to the species as Flabellina sp. 2. The naming of this species is one of hundreds of new bits of information on the opisthobranchs of this coastline that has come out since that book was released. A supplement has now been published, updating the entire book. It includes newly discovered species, new species names, name changes as well as geographic and biological information. Feel free to print this document out and share it with your Brancher friends.

As seen in the photo here, the body is pink to red, with white flecks on the cerata. The rhinophores and cephalic tentacles are purple. The size of the species ranges from 15-30mm.

The radular formula for the species is 36 x 1.1.1. The rachidian tooth bears 5-6 triangular denticles as shown here. The margin teeth bear 15-20 denticles.

Originally the species is documented to occur at Magdelena Bay, Baja California and Islas Ladrones, Panama. Bertsch et al. (2000) extended the range northward to Punta Eugenia, Baja California. The species has also been observed as far south as La Paz, Baja California sur (Angulo-Compillo, 2002), and Puerta Vallarta (Hermosillo-González, 2003) and Costa Rica (INBIO, 2003).


Angulo-Campillo, Orso. 2002. New distributional records of Opishobranch molluscs from the Gulf of California, Mexico. The Festivus 34(10): 117-121.
Bertsch, H., O.A. Campillo & J.L. Arreola. 2000. New distributional records of opisthobranchs from the Punta Eugenia region of the Baja California peninsula, a record based on 1997-1998 CONABIO-sponsored expeditions. The Festivus 32(7): 99-104.
Behrens, David W. 1991. Pacific Coast Nudibranchs, A guide to the opisthobranchs Alaska to Baja California. Sea Challengers. Monterey, CA. 107pp. Second edition.
Behrens, David W. 2004. Pacific Coast Nudibranchs, Supplement II: New Species to the Pacific Coast and New Information on the Oldies. Proc. Calif. Academy Sciences. 55( 2): 11-54.
Hermosillo-González. 2003. New distributional records (Mollusca: Opisthobranchia) for Bahia de Banderas, Mexico (Eastern Pacific). The Festivus 35(3): 21-28.
INBIO. 2003. Sea Slugs of the Pacific coast of Costa Rica .

Dave Behrens
Danville, Calif
July, 2004

Taxonomic information courtesy of:

David W. Behrens

Author: Pacific Coast Nudibranchs
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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