Mangrove Jelly/Upside down jellyfish??

[Jamdiver]

Hey all quick query,

Saw this rather odd critter on a dive recently..

A friend of mine who's knowledgeable in marine life told me that it's a mangrove jelly or upside down jellyfish and that they on occasion will lie upside down on the sand and photosynthesis (apparently they have some sort of symbiotic algae in them).

Any thoughts is this correct and could I get a scientific name here?
Pic taken in about 18fsw in Discovery Bay, Jamaica..

 

[isurus]

cassiopeia is the genus name for the upside down jelly I know of.

 

[knotical]

Your friend seems to be right on. Perhaps Cassiopea frondosa.

 

[Rick Murchison]

Concur. Common around mangroves.
Very nice pix... thanks!
Rick

 

[archman]

Those are the best macro's of those things that I've ever seen.

 

[Jamdiver]

Thanks archman, at first I thought it was some sort of massive nudibranch.
Really had no clue that it was a jellyfish.

 

[Ironcat]

Cassiopeia Jellyfish, so named because they "recline". See Google for the mythological reference. Totally stingless (well, to people anyway) and the first jellyfish I ever touched on purpose. Seacamp 8th Grade.

 

[Dean810]

They were funny things, when I first saw them. I couldn't get them to go right side up, no matter how hard I tried! I guess it just depends on your perspective!

 

[dumpsterDiver]

They have photosynthetic algal cells which they are trying to expose to the maximum amount of sunlight.

 

[drbill]

Here is a link to one of my "Dive Dry with Dr. Bill" newspaper columns that I wrote on the species in the Florida Keys. It may be the same one:

http://www.starthrower.org/products/DDDB/DDDB_100-149/DDDB_136 upside-down jelly.htm