Marionia sp. ?
There is a group of Marionia that just drives me crazy. I am hopeful that Sea Slug Central at the California Academy of Sciences in San Francisco will iron out the dilemma soon.
Marionia rubra was described in 1828 by Ruppell & Leuchart, and M. arborescens was described in 1890 by Rudolph Bergh. Since that time variations we are calling Marionia sp. 1 and sp. 2 in Indo-Pacific Sea Slugs (page 337) have been found. This is another example of specimens looking quite different (color wise), but when you describe them in words, they don't sound that different - maybe it's just a matter of variation.
Both of these specimens were photographed in Sabang, and I have to agree they sure look different. Are they Marionia rubra or M. arborescens or one of the undescribed species mentioned above?
Both have dorsal tubercles, with touches of white. Hard to see the frontal veil, but the velar tentacles look simple. Both have highly branched gills. The sheaths of their very cool rhinophores do seem similar to M. rubra, but different than those in M. arborescens, but is this enough to say they are in fact separate species. Heck I don't know, I need to look at the internals - radula, stomach plates, reproductive system, etc.
Okay so - what's your guess?
WEBMASTER'S NOTES: For you underwater photographers, the best time to photograph these soft-coral feeding Tritoniids is at night! Allow about an hour after sunset and hit the water! That is also the time that you may find predators like Gymnodoris Aurita which like to lurk in the vicinity for a tasty night time snack! Sometimes it can appear that that it is just the reverse as in a posting on Bill Rudman's Seaslug Forum, but I agree with Bill that it is the Marionia that is in the process of being dined on! Night time is the "right time" as the old saying goes.' Once again I would like to thank Martin and Sonja for sharing their images. Readers can certainly look forward to seeing more of their pics in the future!
Martin and Sonja at the Taj Mahal, Agra, India
We dive for over 20 years around the world, but mainly in tropical waters as in the Indo-Pacific. We love diving, like any big fish, especially sharks but our heart belongs to the colorful small animals such as nudibranchs, from which we until now about 500 in 1500 shared dives could find. I photograph the moment with Olympus E-520 and Sea & Sea YS 110 flashes. In my collection are now more than 100,000 photos. www.martin-busch.magix.net
Send Martin email at firstname.lastname@example.org
WEBMASTER'S NOTES : Martin and Sonja are long time contributors to the Slug Site. As in many husband and wife teams, I suspect as Martin suggests, it is Sonja that finds the many nudibranchs that have found their way to presentation on the Site. Martin's skills as a photographer are unsurpassed! A couple of years ago in Bali, I had the good fortune to run into Martin and Sonja at Dive Paradise in the Tulamben area. After dinner Martin showed fellow divers his images taken that day! These were all unedited images, but nevertheless, I didn't see any that I would throw away. Martin certainly knows his system and how to get the best results out of it! What more can be said?
Martin has added three excellent shows from Bali, Alor, South Australia and more recently Anilao to his website that are certainly worthy of your attention. How Martin was able to get some of these photos is beyond me!