Opisthobranch of the Week is Elysia sp.

Elysia sp.

Images courtesy of Andrew Podzorski
Wageo Dive Site in Raja Ampat

Image courtesy of Andrew Podzorski

Elysia sp. (Undescribed)
Members of the genus Elysia are my least favorite to identify. This specimen is a good example of why. Nudibranch and Sea Slug Identification, Second Edition includes 48 species we were not able to identify. Go figure.
When I examine this species carefully, I see an elysid-shaped species, green with an orange mantle edge and black specks and small white papillae covering the mantle. The shape of the critter is compromised in the photo as I believe it is crawling on a piece of algae. Had it been laying flat I am sure it would look like a true Elysia.
Surfing through the species in NSSI 2nd Ed, the closest match I can come up with is Elysia sp. 19 (page 421). The photo and text match Andrew's critter pretty well, except our text on this species states that it does not have a marginal band. Not sure why as the photographed specimen clearly has that feature.
But then one might argue that this is Elysia tomentosa Jensen, 1997, which also has a light mantle margin and numerous papillae on the mantle surface. Oh, but heck, you might even argue that it is similar to Elysia sp. 17., sp. 18 or even sp. 29.
In any event, it is a pretty cool looking creature, whether we can ID it or not. I'll leave the final ID up to you, the reader. Good luck.

Dave Behrens
Sammamish, WA 98074
Dec., 2023
Send Dave email at davidwbehrens@gmail.com

Started diving in 1977 with the Jamaica branch of the British Subaqua Club (JSAC). I qualified as a BASC Advanced Diver/CMAS *** in 1978. As a freshwater botanist in the University of the West Indies, I had collaborative projects with the marine labs at Port Royal and Discovery Bay. I had the privilege to be personally taught about Caribbean corals by Nora Goreau. My first underwater photos were taken in Jamaica with a NIkonos 2! It was impossible not to become passionate about reefs with the great people in the JSAC and the marine labs. I left Jamaica in 1980 with some 425 dives and spend a short time diving with the Institute of Marine Affairs in Trinidad. There I helped with research collection of sponges on the north coast of Trinidad, on Chacachacare and in the Grand Boca, and we even found a new species of ahermatypic coral. Moving on from there, I did some freshwater diving in the USA and cold water diving in southern Sweden, snorkeling and free diving in the Galapagos, before returning to reef diving on the west cost of Saudi Arabia, Queensland, the Philippines, Thailand, and quite extensive diving in mid to eastern Indonesia. Quite some time ago I stopped counting dives when I reached 2000, though I take notes, documentary photos and record the profiles of all dives.

With the travel restrictions imposed by Covid, and finding out how little money is donated to charities supporting reef conservation, I decided to use my knowledge and photos to create a website to encourage people to donate to Greenpeace, Sea Shepard, Conservation International etc. Reef Image-Stories - Help save our reefs!

Camera: Nikon D750 with a Nikon 105mm macro objective in a Seacam housing with Seacam Seaflash 100D strobes.

Send Andrew email at acpuhl@outlook.com

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

Send Dave email at davidwbehrens@gmail.com