Porpitidae
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| Goldfuss , 1818 |
The Porpitidae are a family of hydrozoa (Hydrozoa) from the tribe of the cnidarians (Cnidaria) that live exclusively in the sea . It is a very small family with currently only three species in two genera .
features
The hydroid polyps are colonial but highly differentiated. When ripe, they are mobile and float on the surface of the water as a raft. The soft body is supported by an internal chitin structure. This contains air chambers that allow the colony to float on the surface of the water. The hydrants are polymorphic at the bottom of the raft. It is a large, central, tentacle-free feeding polyp that is surrounded by feeding / venereal polyps and defense polyps. The tentacles are capitat or reduced to nettle cell spots.
The medusa has an evenly rounded umbrella and four or eight radial channels. A ring channel is also available. On the exumbrella there are an even number of rows of nettle cells (stenotles); these begin at the marginal buds. The manubrium is short and conical, the mouth rounded. The gonads are arranged perradial or irregularly perradial and interradial. Two opposing thin, marginal tentacles end in large, round nettle cell buttons. Two further adaxial tentacles can also be present. The two or six marginal buds are without tentacles. Ocelles are missing. The cnidome consists of rounded stenoteles, macrobasic euryteles and atric haplonemes. Zooxanthellae are present.
Geographical occurrence
The three species of the Porpitidae are found worldwide mainly in the warmer seas. The sailing jellyfish also penetrates into the western Mediterranean.
Systematics
The Porpitidae family includes only three genera with three species:
- Family Porpitidae Goldfuss, 1818
- Genus Porpema Haeckel, 1888
- Porpema prunella (Haeckel, 1888)
- Genus Porpites Lamarck, 1801
- Porpita porpita (Linnaeus, 1758) ( syn.P. pacifica Lesson, 1826 and P. linneana Lesson, 1843)
- Genus Velella Lamarck, 1801
- Sailing jellyfish ( Velella velella ) (Linné, 1758)
- Genus Porpema Haeckel, 1888
swell
literature
- Jean Bouillon, Cinzia Gravili, Francesc Pagès, Josep-Maria Gili and Fernando Boero: An introduction to Hydrozoa. Mémoires du Muséum national d 'Histoire naturelle, 194: 1-591, Publications Scientifiques du Muséum, Paris 2006 ISBN 978-2-85653-580-6
- 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, Wellington 2007 ISSN 1175-5326 Abstract - PDF
On-line
Individual evidence
- ↑ World Hydrozoa Database family Porpitidae
