Scyphozoa

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Scyphozoa

[‚sī·fə′zō·ə]
(invertebrate zoology)
A class of the phylum Cnidaria; all members are marine and are characterized by large, well-developed medusae and by small, fairly well-organized polyps.

Scyphozoa

 

a class of solitary marine animals of the phylum Coelenterata. Scyphozoans occur in the form of jellyfish or polyps and are radially symmetrical. The gastric cavity is divided by interradial mesenteries into a central cavity and lateral pouches. Many scyphomedusae have a system of digestive canals. The life cycle is characterized by alternating generations (metagenesis). A planula larva develops from an egg and, after settling on a substrate, becomes a scyphistoma, an individual of the polypoid generation. The scyphistoma buds off polyps like itself and releases ephyrae (larvae of the sexually reproducing generation) by constriction (strobilation).

Bodily contact with certain scyphozoans, for example, Rhizostomae, may cause pain and skin burns. Persons have been known to die after being poisoned by individuals of the genus Chirodrophus, which dwell off northern Australia. Some scyphozoans, for example, Rhizostomae and Aurelia, are commercially significant; they are salted and used as food.

The class of Scyphozoa, comprising the orders Discomedusae, Rhizostomae, Coronatae, and Stauromedusae, includes approximately 200 species, which are distributed throughout the oceans of the world, mostly in temperate and tropical waters. Approximately 30 species occur in the USSR.

REFERENCES

Naumov, D. V. Stsifoidnye meduzy morei SSSR. Moscow-Leningrad, 1961.
Bronns, H. G. Klassen und Ordnungen des Tierreichs, vol. 2, part 2, fascs. 1–6. Leipzig, 1936–59.
Kramp, P. L. Synopsis of the Medusae of the World. Cambridge, 1961.

D. V. NAUMOV

References in periodicals archive ?
Population-level perspectives on global change: genetic and demographic analyses indicate various scales, timing, and causes of scyphozoan jellyfish blooms.
Concentric rings, weakly disc-like shapes, radial structures (including radial cracks), a range of taphonomic grades (from well- to poorly preserved) and peripheral troughs are common features of fossil scyphozoan medusae (Schafer 1941, 1972; Muller 1984; Bruton 1991; Young and Hagadorn, 2010).
However, despite attempts to get taurine antibodies to work on several scyphozoan species and with multiple technique modifications, convincing taurine-IR staining was not obtained in our hands.
Surrounding the rhopalium, the epithelium of the rhopalial niche also contained a dense FMRFamide-IR network, much like that of the scyphozoans (Satterlie and Eichinger, 2014).
TPA was also effective in inducing metamorphosis in the larvae of two hydrozoans, Hydraetinia echinata (Muller, 1985; Schneider and Leitz, 1994) and Mitrocotnella polydiademata (Freeman and Ridgway, 1990); a few scyphozoans (Hofmann et al.
Scyphozoan medusae have marginal lobe organs, termed rhopalia; in Aurelia aurita these have, since Romanes (19), been considered to be integrative loci for swimming activities, photoreception, and gravity sensitivity (20-26).
The histological process during excystment is not well understood in scyphozoan jellyfishes, and this is to be clarified in N.
Genetic evidence of cryptic species has raised estimates of scyphozoan species richness 2-to-10-fold (Dawson, 2004; Hamner and Dawson, 2009).
Conservation of a unique morphology such as the scyphozoan ephyral stage may involve selective advantages of that morphology.
Consequently, the early development of scyphozoan ephyrae appears to be a process that maximizes overall bell diameter increase, and tissue is added to the inter-lappet cleft regions only as needed to maintain the hydrodynamic continuity of the bell as a paddle.
The field-collected samples of Symbiodinium were derived from the scleractinian coral Madracis mirabilis; the sea anemones Aiptasia pallida, Bartholomea annulata, Condylactis gigantea, and Lebrunia danae; and the scyphozoan Cassiopeia xamachana.
Localization and quantification of carbonic anhydrase activity in the symbiotic scyphozoan Cassiopeia xamachana.