Gymnodoris rubropapillosa

Gymnodoris rubropapillosa (Bergh, 1905)

Early on during a classic "muck dive" at the now world-famous Kungkungan Bay Resort , Sulawesi, I was photographing a scorpionfish when my wife Marcia approached, gave me an excited double thumbs-up sign, and pointed down the black sand slope. Thirty feet away a white nudibranch covered with orange polkadots was crawling across the bottom. It was new to both of us and one of the most striking slugs either of us had ever seen. More than that, a large white and orange shrimp clung head-down to its side, using its two large claws to work the sand as the slug lumbered along. I took only two pictures, fearful that I would run out of film halfway through the dive. (This seems to happen on virtually every dive at KBR no matter how frugal with film I am. Any photographer who has been there will know what I mean.) Now, of course, I wish I had shot more frames, or at least taken more care with the two I did shoot, for both turned out a bit overexposed and the slug, by all accounts, is quite rare.

At dinner that night we heard the fascinating story of this colorful pair. The Gymnodoris had been a "regular" at the site for some time, but minus the shrimp. The latter, it seems, had originally been riding a large Risbecia tryoni, also a "regular." Now nudibranchs, as we all know, have a short lifespan and one day Kevin, the KBR manager, found the Risbecia dead, apparently of natural causes. The commensal shrimp, languishing on the wasted corpse, was clearly in trouble. Having just seen the Gymnodoris not too far away, Kevin had the bright idea to "rescue" the shrimp by moving it to a new host. This he did, and when Scott and Janine Michael came onto the scene a few minutes later Kevin with some excitement showed them the dead Risbecia on one side and the Gymnodoris with shrimp on the other. With animated gestures and frequent double "V" victory signs he tried to communicate that he had rescued the shrimp. Scott and Janine, however, were not amused. They knew the shrimp belonged to the Risbecia, dull though it might be. They thought Kevin had clumsily squashed it while putting the shrimp on the more colorful Gymnodoris, perhaps as a photo op for KBR guests. After the dive, a classic "tempest in a teapot" started to brew as Scott and Janine seriously considered complaining to KBR's owners of this most unethical, un-ecological conduct on the part of the resort manager. Later, of course, the true story came out and everyone had a good laugh..

While corresponding with Mike after the trip I mentioned the Gymnodoris and shrimp pair and he immediately emailed back "Small world--at a party last night I saw a video of a Gymnodoris rubropapillosa and a shrimp taken at KBR." A few days later he emailed again to say that the video is now available on the web at Go to films and view "Magnificent Muck" by Bruce Robison. But remember, you heard it on the SlugSite first!

John Hoover
Honolulu, Hawaii
March 2001

Webmaster's Note: Gymnodoris rubropapillosa first appeared on the Slug Site in 1998 as a BOW . As John has indicated, this branch seems to somewhat rare unless you happen to live on Okinawa with Bob Bolland where it appears to be almost common at one particular spot. We looked for this branch in the Philippines for years before Terry Gosliner finally found one in the Batangas area.

This same shrimp ( Periclimenes imperator ) was photographed by local U/W photographer Steve Drogin at KBR in Oct. 1997 on an undescribed Tambja, and later also appeared as a BOW on the Slug Site. Dave Behrens was kind enough to do the write up on this one.

Photos and Text courtesy of John Hoover

John and Marcia Hoover live in Honolulu, Hawaii. John has published two books on marine life of the Hawaiian Islands. His third, a field guide to the marine invertebrates of the Hawaii,is available now. With over 600 photographs, it covers over 500 species, including 66 of Hawaii's most colorful and interesting opisthobranchs. Updates and errata for John's invertebrate book are now available. Email John for a copy.

Hawaii's Fishes, a Guide for Snorkelers, Divers and Aquarists Mutual Publishing, 1993

Hawaii's Underwater Paradise, Mutual Publishing, 1997

Hawaii's Sea Creatures, a guide to Hawaii's Marine Invertebrates. Mutual Publishing, 1999.

John's books are available through Sea Challengers !

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