Antedon

Antedon; Temporal range: Cretaceous - Recent PreꞒ Ꞓ O S D C P T J K Pg N
	Antedon mediterranea
Scientific classification
Kingdom:	Animalia
Phylum:	Echinodermata
Class:	Crinoidea
Subclass:	Articulata
Family:	Antedonidae
Genus:	Antedon; de Freminville, 1811 [1]
Species
	See text.

Antedon is a genus of free-swimming, stemless crinoids. The genus first appeared in the fossil record in the Cretaceous period.[2]

Characteristics

Members of this genus have no stems but have five pairs of feathery arms arising from a central concave disc. There are a number of cirri or unbranched appendages on a low, cone-shaped dorsal ossicle, a bone-like structure in the centre of the disc. The mouth and the ambulacral grooves are also on the upper surface. Clawed cirri on the lower surface provide temporary attachment to the substrate.[3] There is great variability in the morphological features in Antedonids found in different habitats and the main distinguishing feature among the species is the number of cirri.[4]

Species

The following species are recognised in the World Register of Marine Species:[1]

Antedon arabica AH Clark & AM Clark
Antedon bifida (Pennant, 1777)
Antedon duebeni Böhlsche, 1866
Antedon mediterranea (Lamarck, 1816)
Antedon nuttingi (AH Clark, 1936)
Antedon parviflora (AH Clark, 1912)
Antedon petasus (Düben & Koren, 1846)

gollark: Which is correct, though?

gollark: Those are literally the complements of each other, so you can't have one matter and the other not matter.

gollark: I cannot, say, begin taking public transport 50% more, and immediately make everyone else do so.

gollark: Yes. Which is nevertheless not hugely large.

gollark: Collective actions would. Your individual action won't do much unless you somehow simultaneously convince everyone else.

References

Antedon - de Freminville, 1811 World Register of Marine Species. Retrieved 2011-10-13.
Antedon pinnulata The Fossil Museum. Retrieved 2011-10-13.
Family Antedonidae Marine Species Identification Portal. Retrieved 2011-10-13.
De Domenicoa, F.; S. Giacobbea; P. Rinellib (2009). "The genus Antedon (Crinoidea, Echinodermata) in the Strait of Messina and the nearby Tyrrhenian Sea (Central Mediterranean)". Italian Journal of Zoology. 76 (1): 70–75. doi:10.1080/11250000802086011.

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[WoRMS-1] Antedon - de Freminville, 1811 World Register of Marine Species. Retrieved 2011-10-13.

[2] Antedon pinnulata The Fossil Museum. Retrieved 2011-10-13.

[3] Family Antedonidae Marine Species Identification Portal. Retrieved 2011-10-13.

[4] De Domenicoa, F.; S. Giacobbea; P. Rinellib (2009). "The genus Antedon (Crinoidea, Echinodermata) in the Strait of Messina and the nearby Tyrrhenian Sea (Central Mediterranean)". Italian Journal of Zoology. 76 (1): 70–75. doi:10.1080/11250000802086011.