Trichydra pudica
| Trichydra pudica | ||||||||||||
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| Systematics | ||||||||||||
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| Scientific name of the family | ||||||||||||
| Trichydridae | ||||||||||||
| Hincks , 1868 | ||||||||||||
| Scientific name of the genus | ||||||||||||
| Trichydra | ||||||||||||
| Wright , 1858 | ||||||||||||
| Scientific name of the species | ||||||||||||
| Trichydra pudica | ||||||||||||
| Wright , 1858 |
Trichydra pudica is a marine species of the Hydrozoa (Hydroza). It is the only species in the Trichydra genus , which in turn is the only genus inthe Trichydridae family .
features
The hydroid polyps are sessile and connected by stolons; the stolons are covered with a thin perisarc . The hydranth have a collar-like tube at the base. They only have a single ring of filiform tentacles. Gonophores are not known, nor is the cnidoma known.
The medusa measures two to 4 mm in diameter. The umbrella is bell-shaped or almost hemispherical with a rounded, apical extension consisting of thickened mesogloea . She has no gastral handle. The manubrium is relatively large and takes up about 2/3 the height of the screen. Four large lips with wavy edges are formed around the roughly square mouth. There are four radial channels, the numerous centripetal channels are finely branched. The pillow-shaped gonads covers almost the entire interradial outside of the manubrium. There are 30 to 40 solid marginal tentacles with basal thickening. There are no ocelli .
Geographical occurrence
The species is known to date from two geographically distant locations, the eastern North Atlantic and the Pacific Ocean off Canada. It is also occasionally found in the southern and northern North Sea.
Systematics
The family Trichydridae or the genus Trichydra is monotypic, i. that is, they contain only one species, Trichydra pudica (Wright, 1858). A second species, which in the meantime has been assigned to the genus Trichydra , Pochella oligonema Hartlaub, 1917 is now assigned to the genus Fabienna Schuchert, 1996.
Trichydra pudica (Wright, 1858) was originally only known from the polyp generation. In 1973 C. Edwards recognized that the medusa described under the name Pochella polynema Hartlaub, 1917 , the generation of polyps was unknown in this species, in reality it is the medusa of Trichydra pudica (Wright, 1858). Pochella polynema Hartlaub, 1917 is therefore a younger synonym of Trichydra pudica (Wright, 1858), Pochella Hartlaub, 1917 is a younger synonym of Trichydra Wright, 1858.
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literature
- Jean Bouillon, Cinzia Gravili, Francesc Pagès, Josep-Maria Gili and Fernando Boero: An introduction to Hydrozoa. In: Mémoires du Muséum national d'Histoire naturelle. 194 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
- ^ Charles Edwards: The hydroid Trichydra pudica and its medusa Pochella polynema. Journal of the marine biological Association of the United Kingdom, 53: 87-92, Plymouth 1973 ISSN 0025-3154