| 3rd | Top animal classes |
| Scyphozoa | |
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| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Cnidaria |
| Class: | Scyphozoa |
Scyphozoa is a class within the phylum Cnidaria[1], sometimes referred to as the "true jellyfish".
The class name Scyphozoa comes from the Greek word skyphos (σκύφος), denoting a kind of drinking cup and alluding to the cup shape of the organism.
Scyphozoans range from the Ediacaran time period through the Recent. The medusa form is typically the dominant life stage, as opposed to the polyp. As medusae, they eat a variety of crustaceans and fish, which they capture using stinging cells called nematocysts. The nematocysts are attached to the tentacles that radiate downward from the edge of the umbrella dome. Scyphozoans display a four-fold symmetry and have an internal gelatinous material called mesoglea. Scyphozoans have no durable hard parts, including no head, no skeleton and no specialized organs for respiration or excretion.[2][3] Marine jellyfish can consist of as much as 99% water and therefore are rarely found in fossil form.
Unlike other Cnidarians, scyphozoans lack a velum, which is a circular membrane umbrella that propels the jellyfish through the water. While scyphozoans lack this specialized locomotive device, they are able to move through the water by contracting and relaxing the muscles of their umbrella.[4] The periodic contracting and relaxing propels the jellyfish through the water, allowing it to escape predation or catch its prey.
It includes the genus Aurelia.[5]
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Scyphozoa
Main Page
Cladus: Eukaryota
Supergroup: Unikonta
Cladus: Opisthokonta
Regnum: Animalia
Subregnum: Eumetazoa
Phylum: Cnidaria
Classis: Scyphozoa
Subclassis: Discomedusae
Ordo: Coronatae
Scyphozoa Götte, 1887
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For more multimedia, look at Scyphozoa on Wikimedia Commons. |
[[File:|thumb|250px|Aurelia aurita: moon jelly in a Danish fjord]] The Scyphozoa is a class of the phylum Cnidaria, sometimes referred to as the "true jellyfish". There are 200 species. The name Scyphozoa comes from a Greek word which refers to the cup shape of the jellyfish.
The medusa form is the dominant life form, as opposed to the polyp. They eat crustaceans and fish, which they capture using stinging cells called nematocysts. The nematocysts are attached to the tentacles that hang down from the edge of the umbrella dome. Scyphozoans have an internal jelly-like material. They have no hard parts, no head, and no specialized organs for respiration or excretion.
Unlike other types of jellyfish, scyphozoans lack a velum, a circular membrane which propels other jellyfish through the water. Scyphozoans move through the water by contracting and relaxing the muscles of their umbrella.
  | Exceptionally preserved jellyfishes from the Middle Cambrian - PLoS ONE: Exceptionally Preserved Jellyfishes from the Middle Cambrian |
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