Rathkeidae
| Rathkeidae | ||||||||||||
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Rathkea octopunctata , illustration |
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Rathkeidae | ||||||||||||
| Russell , 1953 |
The Rathkeidae are a marine family of the Hydrozoa (Hydrozoa). The family currently includes around 20 species.
features
The species whose hydroid polyps are known are colonial and grow out of branchy stolons. The hydrants are monomorphic, i. H. without differentiation. They have no stems and a wreath of filiform tentacles.
The Medusa buds form directly from stolons or rarely at the base of the hydrant. The medusa are bell-shaped and measure about 2 to 4 mm in diameter. The manubrium has either four elongated lips that form simple or branched mouth tentacles with end buttons or unbranched perradial mouth tentacles that insert vertically or very obliquely at the level of the mouth. They have four or eight radial channels and one ring channel. There are usually eight bulbs, on which usually more than one tentacle arises, rarely only one tentacle per bulge. Ocelli are not trained. Immature medusa can form medusa buds that are perpendicular to the surface. The gonads surround the manubrium.
Geographical occurrence
The family occurs in the Red Sea, the tropical Pacific and the North Atlantic, a species also in the North Sea.
Systematics
According to the "World Hydrozoa Database", the family includes five genera:
- Allorathkea Schmidt, 1972
- Lizzia Forbes, 1846
- Podocorynoides Schuchert, 2007
- Pseudorathkea Xu & Huang, 1990 (considered a synonym of Allorathkea by Bouillon et al., 2006)
- Rathkea Brandt, 1838
supporting documents
literature
- Jean Bouillon, Cinzia Gravili, Francesc Pagès, Josep-Maria Gili, Fernando Boero: An introduction to Hydrozoa. Mémoires du Muséum national d'Histoire naturelle, 194: 1–591, Paris 2006, ISBN 2-85653-580-1
- Marymegan Daly, Mercer R. Brugler, Paulyn Cartwright, Allen G. Collin, Michael N. Dawson, Daphne G. Fautin, Scott C. France, Catherine S. McFadden, Dennis M. Opresko, Estefania Rodriguez, Sandra L. Romano, Joel L. Stake: The phylum Cnidaria. A review of phylogenetic patterns and diversity 300 years after Linnaeus. Zootaxa, 1668: 127-182, 2007 abstract (PDF; 406 kB) .
