''Stellamedusa'' is a genus of

jellyfish Jellyfish and sea jellies are the informal common names given to the medusa-phase of certain gelatinous members of the subphylum Medusozoa, a major part of the phylum Cnidaria. Jellyfish are mainly free-swimming marine animals with umbrella- ...

. The genus is monotypic with a single species recognized, ''Stellamedusa ventana''. The species was first described in the ''Journal of the Marine Biological Association'' in 2004 by Kevin Raskoff and George Matsumoto of the

Monterey Bay Aquarium Research Institute The Monterey Bay Aquarium Research Institute (MBARI) is a private, non-profit oceanographic research center in Moss Landing, California. MBARI was founded in 1987 by David Packard, and is primarily funded by the David and Lucile Packard Foundation ...

. As of February 2004, seven specimens have been observed, five off the

California California is a U.S. state, state in the Western United States, located along the West Coast of the United States, Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the List of states and territori ...

coast in

Monterey Bay Monterey Bay is a bay of the Pacific Ocean located on the coast of the U.S. state of California, south of the San Francisco Bay Area and its major city at the south of the bay, San Jose. San Francisco itself is further north along the coast, by a ...

and two in the

Gulf of California The Gulf of California ( es, Golfo de California), also known as the Sea of Cortés (''Mar de Cortés'') or Sea of Cortez, or less commonly as the Vermilion Sea (''Mar Bermejo''), is a marginal sea of the Pacific Ocean that separates the Baja Ca ...

. Unlike most medusae, they lack marginal tentacles. Specimens so far found reach almost 10 cm in diameter, which is large for a scyphomedusa. The bell is blue-white in colour. The exumbrella is white, and this and the four oral arms are covered with large nematocyst-laden projections filled with stinging cells, enabling the jelly to capture food items of a variety of sizes; it seems to prefer large prey, up to half its size, which is unusual in jellies that capture prey with their bells rather than with tentacles. The bumpy appearance that the stinging cells give to the jelly led to its common name. The species name comes from the remotely operated vehicle ( ROV) ''Ventana'', a deep-diving

robot A robot is a machine—especially one programmable by a computer—capable of carrying out a complex series of actions automatically. A robot can be guided by an external control device, or the control may be embedded within. Robots may be c ...

submarine A submarine (or sub) is a watercraft capable of independent operation underwater. It differs from a submersible, which has more limited underwater capability. The term is also sometimes used historically or colloquially to refer to remotely op ...

that first recorded the jelly on video in 1990. ''Stellamedusa ventana'' has so far been observed only at mesopelagic depths, i.e. between 150 and 550 meters. At these depths, sunlight does not penetrate, but there is still a reasonable amount of oxygen. Many species of jellyfishes live at this level, and it is likely that ''S. ventana'' feeds primarily on other jellies. Another large jellyfish discovered by the same researchers is '' Tiburonia granrojo''.

External links

MBARI press release about the discovery of ''S. ventana''
Ulmaridae Scyphozoan genera Cnidarians of the Pacific Ocean Marine fauna of North America Marine fauna of the Gulf of California Western North American coastal fauna Fauna of California Monotypic cnidarian genera {{Scyphozoa-stub