The genus of true jellyfish known as Cassiopeia, or the upside down jellyfish, includes 8 different species that thrive mainly in warmer region and can be found anywhere from mangroves and coastal regions to canals and mudflats. The coast of Florida and the Caribbean are commonly teeming with these types of jellyfish. The name of the genus is given by the species’ tendency to live on the seabed upside down. They are also quite varied in shape and color, ranging from green and brown to various shades of white and blue.
Cassiopeia and Its Physical Traits – A Closer Look at the Upside Down Jellyfish
Species of the genus Cassiopeia are often mistaken for sea anemone due to their similar appearance. They are mainly photosynthetic, so they have only a mild sting bean. Also, as their name would suggest, they are upside down, so their bell points to the seabed and acts similarly to a suction cup designed to stabilize the jellyfish on the bottom. The tentacles point upwards, and they feature many branches meant to help the jelly capture its prey more easily. Replacing the mouth are a number of small oral openings that guide the food from the tentacles to the stomach.
Cassiopeia Species and Their Feeding Habits
The upside down jellyfish uses a type of mucus and nematocysts that work together to paralyze its prey and get it ready for consumption. They feed mainly on small organisms, and they use the mucus – which is essentially invisible – as a net designed to catch small organisms and immobilize them. Some of the species, such as Cassiopeia andromeda, live in a symbiotic relationship with algae species like the photosynthetic dinoflagellate, Zooxanthellae and various species of shrimp. The Zooxanthellae and their photosynthetic algae are assisted by the jellyfish to gain access to more sunlight. In exchange, the upside-down jelly is provided with extra food. Shrimp benefit differently from their relationship with the jellyfish, living underneath it for protection, while clearing its tentacles from parasites.
An Overview of the Main Types of Upside-Down Jellies
Cassiopea xamachana and C. Andromeda are two of the most significant varieties of Cassiopeia species. The relatively small medusae can grow up to sizes between 10 and 30 cm, and they are both widespread – usually being found in the warmer areas of the Atlantic Ocean and the Caribbean. Other notable species of upside down jellyfish include C. depressa, medusa, ndrosia and frondosa.