Semaeostomeae

Semaeostomeae
Sea nettles, Chrysaora fuscescens
Scientific classification
Kingdom:	Animalia
Phylum:	Cnidaria
Class:	Scyphozoa
Order:	Semaeostomeae L. Agassiz, 1862

The Semaeostomeae (literally "flag mouths") are 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^[3]
• Family Ulmaridae

Gallery

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  "Discomedusae" plate from Ernst Haeckel's Kunstformen der Natur, 1904

References

1. Barnes, Robert D. (1982). Invertebrate Zoology. Philadelphia, PA: Holt-Saunders International. p. 149. ISBN 0-03-056747-5.
2. 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
3. Straehler-Pohl, I., C. L. Widmer, and A. C. Morandini (2011). Characterizations of juvenile stages of some semaeostome Scyphozoa (Cnidaria), with recognition of a new family (Phacellophoridae). Zootaxa 2741: 1-37

• 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.