Monday, August 6, 2007

A New Nudibranch For Me

Once again I spent the majority of my weekend underwater in the Grotto, looking for cool and interesting creatures to take pictures of. I spent plenty of time with my old buddies Halgerda guahan and Halgerda malesso, and saw a bunch of new egg ribbons. I believe that the Halgerda malesso are about 2 weeks behind the guahan in their mating and laying of egg ribbons, but again, that is speculation on my part from what I've been observing. Toward the end of my 2nd dive Sunday afternoon, I had a bunch of decompression time to burn off, so I was up in the 20' depth area, just looking around the rocks to see if I could see anything new or unusual. That's when I came across the guy in the picture above. It's a well established fact that my eyes really aren't that good for close up viewing, so when I first saw this, I thought it was some sort of weed or algae growing on the rock. It looked like it had little leaves blowing in the current, but the more I watched I noticed it was slowly moving forward. Then I looked closer and determined that it was indeed some sort of critter. It was 2-3" in length and about 1/4" in width. I really couldn't see any detail on it at all underwater, so I was just snapping away hoping the pictures would show up well on the computer. When I got back and put the pictures on my computer, I was amazed at the detail and colors in this little guy, he was absolutely spectacular. I have looked through my nudibranch book, and haven't seen anything exactly like him. Many thanks to Erwin Kodiat on nudipixel.net for identifying this guy as a Pteraeolidia ianthina. Once I found out what it's name was, I look on Sea Slug Forum for more information on this particular nudie. I found quite a bit of information on them from Dr. Bill Rudman, here is what he says about the family:

"Two quite different groups of sea slugs have evolved ways of using the ability of plants to convert the sun's energy into sugars and other nutrients. In simple terms they have become "solar powered".The herbivorous sacoglossans are suctorial feeders removing the cell sap from the algae on which they feed. In most, the cell contents are simply digested by the slug. Some species however have evolved branches of their gut which ramify throughout the body wall and contain plastids, which are the photosynthesising "factories" from the algae, alive and operating. In many cases these plastids are chloroplasts, but sacoglossans that feed on red and brown algae are also reported to keep the plastids from these algae alive as well. As I show elsewhere in the Forum, one species, Elysia cf. furvacauda changes diet and plastid at least three times during its life history.In nudibranchs, which are all carnivorous, many have evolved similar ways of keeping whole single-celled plants (zooxanthellae) alive in their bodies. In most cases the zoxanthellae are obtained from their food, often cnidarians, which already have symbiotic zooxanthellae in their bodies. This symbiosis as evolved many times within the nudibranchs with examples in many quite unrelated families and orders."

So if you're looking for these guys, chances are they'll be fairly shallow, and somewhere they can get direct access to sunlight. In the Grotto, you would want to look for them on the big rocks close to the rock you jump off of to enter the water.

Needless to say, it was a great weekend of diving in the Grotto, and I've got quite a few other pictures to put up as well. But right now I've got a talk show to do, so this is going to have to suffice for the time being!

4 comments:

The Saipan Blogger アンジェロ・ビラゴメズ said...

I stole some of your photos and wrote stuff about your blog over on my blog today.

Bev said...

i knew you'd find other crazy things to blog about!

Harry Blalock said...

That may be Bev, but it doesn't mean I'm not going to be making good use of the pictures a certain someone just sent me. You know the saying, I'm saving the best for last.

Bev said...

grrrrrrrrrr