Pincer stars

Pincer stars
	Pisaster ochraceus
Systematics
Trunk :	Echinoderms (Echinodermata)
Sub-stem :	Eleutherozoa (Eleutherozoa)
Class :	Starfish (asteroidea)
Order :	Pincer stars
Scientific name
	Forcipulatida
	Perrier , 1884

The pincer stars (Forcipulatida) are an order of mostly large starfish that includes six families .

description

The pincer stars have a net-like pattern of calcareous platelets, while edge plates and paxilles are absent. The straight and crossed pedicellariums are stalked and can be found all over the body. The arms are flexible and often rounded in cross-section. The ambulacral feet , usually standing in four rows, have suction pads.

Most pincer stars have five arms, but in the families Heliasteridae and Pycnopodiidae there are predominantly species with significantly more arms, so that they have an external similarity to the not closely related sun stars.

Pincer stars are predators and scavengers who can evert their stomachs for extraintestinal digestion of their prey.

Systematics

According to the World Register of Marine Species , the order Forcipulatida includes 6 families:

Asteriidae Gray, 1840-38 genera

Heliasteridae Viguier, 1878 - 2 genera

Pedicellasteridae Perrier, 1884 - 6 genera

Pycnopodiidae Fisher, 1928 - 2 genera

Stichasteridae Gray, 1840 - 8 genera

Zoroasteridae Sladen, 1889 - 8 genera

Pisaster ochraceus ( Asteriidae )
Labidiaster annulatus ( Heliasteridae )
Pycnopodia helianthoides ( Pycnopodiidae )
Stichaster australis ( Stichasteridae )
Zoroaster fulgens , ( Zoroasteridae )

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

Commons : Forcipulatida - collection of images, videos and audio files

Christopher Mah: Forcipulatida Perrier, 1884 . In: Christopher Mah: World Asteroidea database. World Register of Marine Species , 2015.