Superregnum: Eukaryota
Cladus: Unikonta
Cladus: Opisthokonta
Cladus: Holozoa
Regnum: Animalia
Subregnum: Eumetazoa
Phylum: Cnidaria
Classis: Scyphozoa
Subclassis: Discomedusae
Ordo: Semaeostomeae
Familiae (5): Cyaneidae - Drymonematidae - Pelagiidae - Phacellophoridae - Ulmaridae
References
Straehler-Pohl, I.; Widmer, C.L.; Morandini, A.C. 2011: Characterizations of juvenile stages of some semaeostome Scyphozoa (Cnidaria), with recognition of a new family (Phacellophoridae). Zootaxa, 2741: 1–37. Preview
Vernacular names
suomi: Kiekkomeduusat
русский: Флагомедузы
Semaeostomeae (literally "flag mouths") is an order of large jellyfish characterized by four long, frilly oral arms flanking their quadrate mouths. The umbrella is domed with scalloped margins, and the gastrovascular system consists of four unbranched pouches radiating outwards from the central stomach; no ring canal is present. They usually possess eight tentacles; four are per-radical and four are inter-radical.[1]
Taxonomy
The order consists of five families.
Family Cyaneidae
Family Drymonematidae[2]
Family Pelagiidae
Family Phacellophoridae
Family Ulmaridae
Differentiation
The three traditional families, Pelagiidae, Cyaneidae, and Ulmaridae, are distinguishable by these characteristics:
Gastrovascular cavity divided by radial septa into rhopalar and tentacular pouches
Pouches simple and unbranched – Pelagiidae
Pouches branched – Cyaneidae
Gastrovascular system in form of unbranched and branching canals, or with anastomosing radial canals – Ulmaridae
In addition, members of the Pelagiidae have no ring canal, and the marginal tentacles arise from umbrella margin. Three genera are in this family.
Gallery
"Discomedusae" plate from Ernst Haeckel's Kunstformen der Natur, 1904
"Discomedusae" plate from Ernst Haeckel's Kunstformen der Natur, 1904
References
Barnes, Robert D. (1982). Invertebrate Zoology. Philadelphia, PA: Holt-Saunders International. p. 149. ISBN 0-03-056747-5.
Bayha, K. M., and M. N. Dawson (2010). New family of allomorphic jellyfishes, Drymonematidae (Scyphozoa, Discomedusae), emphasizes evolution in the functional morphology and trophic ecology of gelatinous zooplankton. The Biological Bulletin 219(3): 249–267
Collins, A. G.; Jarms, G.; Morandini, A. C. (2022). "Semaeostomeae". World Register of Marine Species. Retrieved 1 November 2022.
Ruppert, Edward E.; and Fox, Richard S. (1988). Seashore Animals of the Southeast, University of South Carolina Press, 273. ISBN 0-87249-535-3.
Hayward, Peter J.; and Ryland, John S. (1995). Handbook of the Marine Fauna of North-West Europe, Oxford University Press, 65. ISBN 0-19-854055-8.
Bayha K., Dawson M. (2010) New family of allomorphic jellyfishes, Drymonematidae (Scyphozoa, Discomedusae), emphasizes evolution in the functional morphology and trophic ecology of gelatinous zooplankton. Biological Bulletin 219: 249–267.
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