Tuesday, May 27, 2014
up-side down jellyfish
An up-side down jellyfish found in Yal Ku Lagoon, Akumal, Quintana Roo, Mexico (Caribbean).
The up-side down jellyfish, Cassiopea xamanchana, does not have the typical physical characteristics of jellyfish. Often it has a somewhat green or gray/blue coloration. This display is the result of numerous densely packed symbiotic zooxanthellae,Symbiodinium microadriaticum.
The medusa, the dominant adult phase of the life cycle, possesses four branching tentacles that extend from the body, up into the water column. These structures are used in feeding and provide nutrients in combination with what is made available by the photosynthetic dinoflagellates. The large, dome shaped exumbrella of the medusa contains a central depression that is used mainly for attachment purposes as the up-side down jellyfish remains sedentary throughout a majority of its lifecycle.
Animalia - Cnidaria - Scyphozoa - Rhizostomeae - Cassiopeidae - Cassiopea - C. xamachana