Thecacera sp. (undescribed)
Photograph courtesy of Bob Yin

Whao! Just when you think you've seen them all, this one drops out of the sky, and it looks like this one could do just that. I'm sure that no member of the genus Thecacera has been observed to swim like Hexabranchus and others can, but with these long extra-branchial appendages one can imagine that it's got all "The Right Stuff."

We were first introduced to this new species on page 190 of Helmut Debelius' Nudibranchs and Sea Snails. Since then, uncle Bob shot this awesome picture in Malasyia. It's color is as wild as its long wing-like projections. It reminds me of a clown costume with the ruffled collar abound its neck. The body of this currently undescribed species is yellow with dark brown, almost black spots, sparsely dispersed on the body. The same color is found on the tips of the rhinophores, and the extra-branchial appendages.

All members of this genus display aposomatic, or warning coloration. I am unsure however, if this to warn wanton predators of chemical toxins or foul taste, or is just a protective hustle. Like T. picta , T. pacifica and, T. darwini this species can hardly go unnoticed on any reef substrate. Because they are all phanerobranch dorids, and incapable of retracting and protecting their gills within their mantle, maybe they rely on the combination of both the extra-branchial appendages and their bright coloration to protect this vital organ form injury.

Helmut reports that his specimen was 1.5 cm in length, and observed at the Lesser Sunda Islands, Indonesia. Bob's specimen, shown here, extends its geographic range to Malaysia.

As an active member of the San Diego Underwater Photographic Society , Robert Yin has been taking underwater photographs world-wide for over 30 years, specializing in the Philippines. His photographs have appeared in many magazines and books including Skin Diver, Ocean Realm, Discover Diving, Philippines Airlines' Mabuhay Magazine, Action Asia, Asian Diver, National Geographic, Trauchen, Espacio Profundo, Sport Divers Journal, and scientific journals.

He has won many photographic awards including Nikon Photo Contest International. He was a presenter at the 1986, 1990, 1992, 1994 and 1998 San Diego Underwater Film Festivals. His photos have been exhibited in galleries including Sea Center Santa Barbara, S. Birch Aquarium-Museum San Diego, Cabrillo Aquarium, Manila Hotel and the Monterey Aquarium.

His 1997 books are Marine Life for Young Readers by Dominie Press, USA; and Beneath Philippines Seas by Bookmark, Philippines eMail:

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Webmaster's Note: The June/July issue of Asian Diver Magazine is currently featuring a piece by Bob on the Batangas area of the Philippines, one of my favorite diving areas for nudis!

Text courtesy of Dave Behrens
Photos courtesy of Bob Yin

David W. Behrens

Author: Pacific Coast Nudibranchs
Co-Author Coral Reef Animals of the Indo Pacific
Propriator of Sea Challengers Natural History Books !

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