Cuthona longi

Image courtesy of Douglas Klug
Anacapa Island, Channel Islands, California

Image courtesy of Jeff Hamann
Isla Raza, Bahia de los Angeles, Baja California

Cuthona longi Behrens 1985

Some species of sea slugs are extremely common, and we see them on almost every dive or trip to the tidepools. While others, are just the opposite, going AWOL for many years causing some slug-o-philes to wonder if the describer of the species could have made the whole critter up. Polycerella glandulosa Behrens & Gosliner, 1988 and with this's BOW, Cuthona longi is just a couple of them.

Webmaster, Mike ran Cuthona longi soon after I described it in 1985, but it hasn't been seen since. It has been 40 years since Jeff Hamann collected the holotype at Isla Raza, Baja California, Mexico in July of 1982. Forty years have gone by with no sightings of this colorful critter. Go figure.

Doug Klug and I both had trouble identifying his little beauty from Anacapa Island. But after a little scalp scratching and the help of a few fellow Branchers, it hit me - Oh yeah dummy, you described it.

Smooth rhinophores and cephalic tentacles with encrusting white; rounded foot corners; characteristic sub-apical blue band on cerata; and much-lobed, olive cerata cores and encrusting white pigment on notum. Yeap that's it.

Since my description was based on only one specimen, I had no clue to how variable its coloration might be. Comparing Doug's photos with that of Jeff Hamann's (left) from the original description we do see some subtle variation in ceratal coloration, but over this is our critter.

The great thing out Doug's find, reported here for the first time, is his critter is from outside the Gulf of California, in Pacific waters and much farther north, extending the geographic range to the Channel Islands off California.

This goes to show you that new information on our own coast's nudibranch fauna is right there in front of us. Thanks Doug.

Dave Behrens
Sammamish, WA 98074
June., 2022
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Douglas Klug is a SCUBA instructor, underwater photographer, and diving writer based in Santa Barbara, California. Since taking his first underwater breaths on certification dives at the Monterey breakwater over 35 years ago, "Diver" Doug has continued to explore California's waters. Doug attended the University of California, Santa Barbara as an 18-year-old diver and fell in love with the easy access to California's Channel Islands. His favorite diving destinations are Southern California's Channel Islands, where he enjoys photographing the majestic kelp forests, curious marine mammals, and especially likes to find and photograph tiny colorful nudibranchs.

Doug's photo-essays have been published in print world-wide, including articles in California Diving News, DAN Alert Diver, and Dive Training. Doug's images have been used in print and digital formats including by the US National Park Service, US National Marine Sanctuary, the Monterey Bay Aquarium, Google, and Microsoft. Doug has even done live talks on underwater photography for dive clubs and museums in Southern California.

Doug's experience includes being a recreational SCUBA instructor as well as diving with Nitrox and SCC Rebreathers. Doug holds professional level certifications from NAUI, SSI, PADI, NASDS, and TDI. Doug also participates in volunteer scientific diving for organizations like Reefcheck. When he's not taking underwater photos, Doug is still active as an underwater guide for divers not familiar with Southern California Diving. He also still teaches private SCUBA lessons, underwater photography skills, and even offers an on-line NAUI certification course for divers on Southern California nudibranch identification.

You can view Doug's underwater work on his Instagram feed: @divindk, and prints are available on his website at

From left to right, Terry Gosliner, Angel Valdes, Dave Behrens La Jolla, Calif.

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