Thordisa rubescens

Image courtesy of Merry Passage
Merry found it in sixty feet at Golf Ball Reef, a low-laying rocky reef off of Palos Verdes, California
Estimated size 50mm (+)

Photo courtesy of Phil Garner

Thordisa rubescens , Behrens and Henderson 1981

This is a super rare find along the California coast. You can count the number of confirmed sightings on one hand. Interestingly it is not rare due to its size, as all of the observed specimens have been large, measuring up to 90 mm in length.

As the trivial names suggests, the body is bright red-orange. The notum is covered with numerous inflated, spiculose, papillae of various sizes and shapes. There is a scattering of gold flecks in a halo arounf the gill and around each rhinophore.

The radular morphology suggests it feed on sponges, but we have no information on this.

This photo was taken at the type locality, where we described the species originally, Palos Verdes, California.

I want to personally thank both Merry and Phil for making this BOW possible!

Dave Behrens
Sammamish, WA 98074
June, 2016
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WEBMASTER'S NOTES : Who says taxonomic lightning doesn't strike twice on the same animal? Merry was fortunate to find a second specimen this week in the same approximate area! This time she found T. rubescens with it's egg mass , certainly an very uncommon sighting if not a first! Seeing the animal under any circumstances is a feat on to itself! The nudi taxonomists are certainly going to be happy with this photo!

Michael Miller

Merry Passage
Merry Passage worked as a genetics research scientist at Harbor UCLA for three decades. After retiring she has used her degrees from Arizona State University and laboratory experience as an aid to scuba diving. She spends countless hours researching many of the animals we find underwater. Her home office is filled with binders and identification books from algae to whales. She knew instantly that the nudibranch she found was uncommon. After looking at the little information available she felt it was likely Thordisa rubescens.

Thanks to Dave Behrens for his quick response confirming our suspicions.

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

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