#rhizostomeae

[herpsandbirds]

Crown Jelly aka Cauliflower Jelly (Cephea cephea), family Cepheidae, order Rhizostomeae, found in the western Indo-Pacific to northern Australia

photographs by Derek Keats

[uncharismatic-fauna]

Bow Down to the Crown Jellyfish

The crown jellyfish (Cephea cephea), also known as the cauliflower jellyfish, is a species of jellyfish found primarily in the open waters of the Indo-Pacific Ocean, from the surface up to a depth of 915 m (3,000 ft). They spend most of the day in deeper waters, and then rise to the surface at night to feed.

Like most jellyfish, C. cephea is a filter feeder. The bulk of their prey consists of algae, shrimp, plankton, invertebrate eggs and invertebrate larvae. Although they are venomous, they are not considered a threat to humans. Rather, it's venom is designed to deter its natural predator, sea turtles.

The crown jellyfish is named for its distinctive appearance. The 'bell', or umbrella is bright purple, up to 60 cm (23 in) across, and situated in the middle is a bulb of multiple protruding round spikes. Beneath is a cauliflower-shaped mass, often white or yellow, from which the 30-40 thin tentacles descent. In addition to its bright coloring, the cauliflower jellyfish is also notable for being bioluminescent at night and in the darker depths of its range; the purpose of this light show is unclear.

C. cephea is a broadcast spawner, meaning that females and males both release their reproductive material into the open water. The fertilized eggs hatch into microscopic larvae, which then floats through the ocean for months or even years until it encounters a rock, coral, or other sedentary object. There, it grows into a structure called a polyp that filter feeds on passing plankton for another several weeks. When it gets big enough, it undergoes strobilation, in which layers peel off to become tiny jellyfish. These baby crown jellyfish grow extremely quickly, starting at only 2-3 mm (0.07-0.11 in), but grow to to 1.7 cm (0.66 in) in only a few weeks. Once they reach their adult size, they only live for 3-6 months.

Conservation status: The crown jellyfish has not been listed by the IUCN. Due to its large population size and range, it is considered stable, and may even be expanding its range due to warming oceanic waters.

Photos

Derek Keats

Alexia Pihier

[bestanimal]

Round 3 - Scyphozoa - Rhizostomeae

(Sources - 1, 2, 3, 4)

Order: Rhizostomeae

Common Name: “root-mouth jellies”

Families: 10 - Catostylidae (“fat-armed jellies”), Lobonemidae, Lychnorhizidae, Rhizostomatidae, Stomolophidae (“cannonball jellies”), Cassiopeidae (“upside-down jellyfish”), Cepheidae (“crowned jellies”), Mastigiidae, Leptobrachidae (“mosaic jellies”), and Versurigidae

Anatomy: in contrast to other scyphozoans, they have neither tentacles nor other structures at the bell's edges; eight highly branched oral arms, which become fused as they approach the central part of the jelly; nematocysts and suctorial minimouth orifices along the oral arms; mouth is subdivided into minute pores that are linked to coelenteron

Diet: zooplankton, crustaceans, and fish

Habitat: oceans worldwide; some species have been known to enter brackish waters

Evolved in: Cambrian

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The Jelly Blubber or Blue Blubber Jellyfish (Catostylus mosaicus) is known to have a symbiotic relationship with photosynthetic algae. The algae lives within the jellyfish, using the sun to produce both energy for itself and for its host. However, most of the Jelly Blubber’s diet is zooplankton, and the energy gifted from the algae makes up only a small portion of its diet. Jelly Blubbers are also seen providing host to the copepod species Paramacrochiron maximum, which will live on the oral arms of the jellyfish and consume extra mucus it produces. This doesn’t harm the jellyfish, nor does it provide any benefit, but the copepod gets protection, food, and a free floating home.

The venom of the Jelly Blubber is currently being studied for potential anticancer effects. The cnidocytes of C. mosaicus hold venom which may have apoptopic effects on A549 cells, the same cells linked to pulmonary adenocarcinoma, a common form of lung cancer. Another study found that gold nanoparticles with Acromitus flagellatus nematocyst venom residue also have anti-proliferative affects on cancer cells. Further study and isolation of jelly venom may lead to new anticancer innovations.

Young spider crabs, of the species Libinia ferreirae and Libinia spinosa, use the inside of the Marbled Jelly’s (Lychnorhiza lucerna) bell as a nursery, keeping them safe from predation.

Jellyfish of this order are considered edible, both as a delicacy and for use in traditional medicine, and are eaten mainly in Asia, typically dried and/or salted, or raw in salads. The Banana Jellyfish (Catostylus perezi), which is incapable of stinging humans but tends to bloom in large amounts in areas of high human activity, contains a large amount of nutrients, making it edible to humans. The Banana Jellyfish helps support malnutrition in communities where food is limited, such as off the coast of Pakistan. The mucin that comes off this jellyfish has also been found to help aid in the relief of joint pain. The Flame Jellyfish (Rhopilema esculentum) has become such a popular seafood item, that it is the subject of aquaculture in China, where it is bred in ponds before being released into a semi-enclosed bay to grow to a mature size suitable for the fishery. Fishing permits are issued around 2 months after the jellyfish are released.

The giant Nomura's Jellyfish (Nemopilema nomurai), the largest Rhizostomeaen, can reach similar sizes as the Lion’s Mane Jellyfish (which is in the order Semaeostomeae), growing up to 2 m (6 ft 7 in) in diameter and weighing up to 200 kg (440 lb). The Nomura’s Jellyfish’s large size and quantity often negatively affects fisheries in East Asia. Aside from humans, their only predators are swordfish, tuna, sunfish, and leatherback sea turtles. A decrease in predators and an increase in favorable conditions and warming seas have caused an explosion in population, displaying that an increase in animal populations is not always a good sign! Scientists are studying their venom for use in medical applications, such as for treating joint disease and in cancer research. The Japanese company Tango Jersey Dairy also produces a vanilla and jellyfish ice cream using Nomura's Jellyfish.

When disturbed, the Cannonball Jellyfish (Stomolophus meleagris) can secrete a toxic mucus out of its nematocysts. The toxin harms small fish in the immediate area, and drives away most predators, except for certain types of crabs.

In Georgia, USA, the Cannonball Jellyfish is known as the “Georgia Jellyball”, and fishing for the species is the state’s third largest commercial fishery. The jellyfish are dried, preserved and packaged before being sold to a seafood distributor that ships them to Japan, China, and Thailand.

Upside-down Jellyfish (genus Cassiopea) (image 3) have a symbiotic relationship with photosynthetic dinoflagellates and therefore, must lie upside-down in areas with sufficient light penetration to fuel their energy source, which also involves certain elements and minerals such as carbon. While the jellies do feed on crustaceans, nematodes, and eggs, they get most of their energy from photosynthesis. They can be seen in colonies of various colors, lying upside-down with their oral arms floating above them, like flattened versions of their anemone cousins.

Some species of Cassiopea have been observed to enter a sleep state, displaying three primary characteristics during this time. These are quiescence, also known as a state of inactivity or dormancy, delayed responsiveness to stimuli, and being able to partake in homeostatic regulation whilst asleep. They are the first animals with no central nervous system to have been observed sleeping.

The Crown Jellyfish (Cephea cephea) is one of the most venomous jellyfish, using large amounts of venom to kill their prey. Despite this, they are not known to be harmful to humans.

The Mediterranean Jellyfish, also known as the Fried Egg Jellyfish (Cotylorhiza tuberculata) (image 4) also has a symbiotic relationship with photosynthetic algae, zooxanthellae, which allows it to photosynthesize on top of consuming plankton. The mutualistic relationship with zooxanthellae is so crucial to the Mediterranean Jellyfish's growth and survival that the preliminary step of premature medusa formation will not initiate without the presence of zooxanthellae, meaning the jellyfish will not mature to adulthood until it is inhabited by the algae.

[saritawolf]

Blue Blubber Jellies (Catostylus mosaicus) - (c) SaritaWolf - please do not repost

[wikipediapictures]

Cephea cephea

“Cauliflower Jellyfish, Cephea cephea at Marsa Shouna, Red Sea, Egypt #SCUBA” - via Wikimedia Commons

[parakaryote]

Day 4 of Invertober: Fried egg jellyfish!

If anyone’s wondering: yes, all of these pictures (so far) are done on the same canvas.

[Image description: A drawing of a fried egg jellyfish (Cotylorhiza tuberculata). The top of its body resembles an egg done sunny-side-up with a deep orange yolk. Its tentacles are thick and curl up at the end, with their undersides being yellow with some blue bumps. The common name is written above, and the taxonomic classification (sans kingdom) is written below. End ID.]

[snototter]

A Barrel jellyfish (Rhizostoma pulmo) off the coast of Cervo, Italy

by Alfiero Brisotto

[animalids]

Crown jellyfish (Netrostoma setouchina)

Photo by Dallas and John Heaton