Paxil stars
| Paxil stars | ||||||||
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| Systematics | ||||||||
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| Scientific name | ||||||||
| Paxillosida | ||||||||
| Perrier , 1884 |
The Paxillosida (Paxillosida) are an order of mostly large starfish that includes 7 families.
description
The Paxillensterne are soft ground inhabitants. Since there is no suction on sand and mud, their ambulacral feet, each provided with two ampoules, have no suction pads. The top is covered with umbrella-like platelets (paxilles). Pedicellariums may be present, but many species are absent.
Paxil stars are predators or scavengers . The stomach cannot be turned forward, which is why the prey is swallowed and digested inside. Most species do not have an anal opening, so indigestible residue is expelled through the mouth opening.
In the Paxillensternen, the free-swimming, plankton- living bipinnaria larva without a brachiolaria stage metamorphosed directly to the starfish.
In the family Astropectinidae all species have five arms, but there are many-arm species in other families, such as the Luidiidae .
Systematics
According to the World Register of Marine Species , the order Paxillosida includes 7 families:
- Astropectinidae Gray, 1840
- Ctenodiscidae Sladen, 1889
- Goniopectinidae Verrill, 1889
- Luidiidae Sladen, 1889
- Porcellanasteridae Sladen, 1883
- Pseudarchasteridae Sladen, 1889
- Radiasteridae Fisher, 1916
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literature
- Christopher L. Mah, Daniel B. Blake: Global diversity and phylogeny of the Asteroidea (Echinodermata) . In: PLoS ONE . tape 7 , no. 4 , 2012, p. e35644 , doi : 10.1371 / journal.pone.0035644 , PMID 22563389 , PMC 3338738 (free full text) - (English).
Web links
- Christopher Mah: Paxillosida Perrier, 1884 . In: Christopher Mah: World Asteroidea database. World Register of Marine Species , 2015.