{{Taxobox
| color = pink
| name = Hadromerida
| status = DD
| status_system = iucn2.3
| image_caption =
| image =
| image_width =
| regnum = [[Animal]]ia
| phylum = [[Porifera]]
| classis = [[Demospongiae]]
| ordo = '''[[Hadromerida]]'''
| ordo_authority = [[Topsent]], [[1894]]
| subdivision_ranks = families
| subdivision = *[[Acanthochaetetidae]] Fischer, 1970 
*[[Alectonidae]] Rosell, 1996 
*[[Choanitidae]]
*[[Clionidae_(Sponges)|Clionidae]] d'Orbigny, 1851 
*[[Hemiasterellidae]] Lendenfeld, 1889 
*[[Placospongiidae]] Gray, 1867 
*[[Polymastiidae]] Gray, 1867 
*[[Sollasellidae]] Lendenfeld, 1887 
*[[Spirastrellidae]] Ridley & Dendy, 1886 
*[[Stylocordylidae]] Topsent, 1892 
*[[Suberitidae]] Schmidt, 1870 
*[[Tethyidae]] Gray, 1848 
*[[Timeidae]] Topsent, 1928 
*[[Trachycladidae]] Hallmann, 1917
| synonyms =
}}
'''''Hadromerida''''' is an [[order]] of [[sea sponge]]s belonging to the class '''[[Demospongiae]]'''.<ref name="ITIS">{{ITIS | ID = 48443 | taxon = Hadromerida| year = 2007 | date = 16 February}}</ref>

Some members of this order are the targeted prey of [[hawksbill turtle]]s.<ref name="ScienceSpongi">{{cite journal | last =Meylan | first =Anne | authorlink =Anne Meylan | title =Spongivory in Hawksbill Turtles: A Diet of Glass | journal =Science | volume =239 | issue =4838 | pages =393-395 | publisher =American Association for the Advancement of Science | date =[[1988-01-12]] | url=http://links.jstor.org/sici?sici=0036-8075%2819880122%293%3A239%3A4838%3C393%3ASIHTAD%3E2.0.CO%3B2-H
| doi = | id = | accessdate = 2007-02-15 }}</ref>

==Bibliography==
* {{ITIS | ID = 48443 | taxon = Hadromerida| year = 2007 | date = 16 February}}

==References==
{{reflist}}
 
{{invertebrate-stub}}

[[fr:Hadromerida]]
[[it:Hadromerida]]
[[nl:Hadromerida]]

2008-02-19T09:33:37Z

Yoruno:

{{unreferenced|article|date=November 2007}}
{{Taxobox
| color = pink
| name = Sea pens
| image = Haeckel Pennatulida.jpg
| image_caption = "Pennatulida" from [[Ernst Haeckel]]'s ''[[Kunstformen der Natur]]'', 1904
| regnum = [[Animal]]ia
| phylum = [[Cnidaria]]
| classis = [[Coral|Anthozoa]]
| subclassis = [[Alcyonaria]]
| ordo = '''Pennatulacea'''
| ordo_authority = [[Addison Emery Verrill|Verrill]], 1865
| subdivision_ranks = [[Family (biology)|Families]]
| subdivision =
*Suborder '''Sessiliflorae'''
**[[Anthoptilidae]]
**[[Chunellidae]]
**[[Echinoptilidae]]
**[[Funiculinidae]]
**[[Kophobelemnidae]]
**[[Protoptilidae]]
**[[Renillidae]]
**[[Scleroptilidae]]
**[[Stachyptilidae]]
**[[Umbellulidae]]
**[[Veretillidae]]
*Suborder '''Subselliflorae'''
**[[Pennatulidae]]
**[[Pteroeididae]]
**[[Virgulariidae]]
}}

'''Sea pens''' are colonial marine [[cnidaria]]ns belonging to the order '''Pennatulacea'''. There are 14 families within the order; they are thought to have a [[cosmopolitan distribution]] in tropical and temperate waters worldwide. Sea pens are grouped with the [[octocoral]]s ("soft [[coral]]s"), together with [[sea whip]]s and [[sea feather]]s.

[[Image:sea pen uprooted.jpg|thumb|left|Uprooted sea pen with the bulbous peduncle in view]]

Although named after their feather-like appearance reminiscent of antique [[quill pen]]s, only sea pen species belonging to the suborder '''Subselliflorae''' live up to the comparison. Those belonging to the much larger suborder '''Sessiliflorae''' lack feathery structures and grow in club-like or radiating forms. The latter suborder includes what are commonly known as '''sea pansies'''.

As octocorals, sea pens are composed of physiologic structures called [[polyp]]s (which look somewhat like miniature [[sea anemone]]s), each with eight [[tentacle]]s. Unlike other octocorals, however, a sea pen's [[polyp]]s are specialized to specific functions: a single polyp develops into a rigid, erect stalk (the ''rachis'') and loses its tentacles, forming a bulbous "root" or ''peduncle'' at its base. Other polyps branch out from this central stalk, forming water intake structures (''siphonozooids''), feeding structures (''autozooids'') with [[nematocyst]]s, and reproductive structures. The entire colony is fortified by calcium carbonate in the form of ''spicules'' and a central ''axial rod''.

[[Image:sea pen2.jpg|thumb|150px|left|Sea pen at [[Vancouver Aquarium]].]]

Using their root-like peduncles to anchor themselves in sandy or muddy substrate, the exposed portion of sea pens may rise up to 2 [[metre]]s in some species, such as the [[tall sea pen]] (''Funiculina quadrangularis''). Sea pens are sometimes brightly coloured; the [[orange sea pen]] (''Ptilosarcus gurneyi'') is a notable example. Rarely found above depths of 10 metres, Sea pens prefer deeper waters where turbulence is less likely to uproot them. Some species may inhabit depths of 2,000 metres or more.

While generally sessile animals, sea pens are able to relocate and re-anchor themselves if need be. They position themselves favourably in the path of currents, ensuring a steady flow of [[plankton]], the sea pens' chief source of food. Their primary predators are [[nudibranch]]s and [[starfish]], some of which feed exclusively on sea pens. When touched, sea pens emit a bright greenish light; this is known as ''[[bioluminescence]]''. They may also force water out of themselves as a defensive act, deflating and retreating into their peduncle.

[[Image:sea pen.jpg|thumb|left|''[[Pennatula aculeata]]'']]

Like other [[Coral|anthozoa]]ns, sea pens reproduce by co-ordinating a release of sperm and eggs into the water column; this may occur seasonally or throughout the year. Fertilized eggs develop into larvae called ''planulae'' which drift freely for about a week before settling on the substrate. Mature sea pens provide shelter for other animals, such as juvenile [[fish]]. Analysis of rachis growth rings indicates sea pens may live for 100 years or more, if the rings are indeed annual in nature.

The sea pen [[fossil]] record is patchy and disputed by some; while the earliest accepted fossils are known from the [[Cambrian]]-aged [[Burgess Shale]] (''[[Thaumaptilon]]''), similar fossils from the late [[Proterozoic]] ([[Ediacaran]]) (ala ''[[Charnia]]'') may represent the dawn of sea pens. Precisely what the Proterozoic fossils are, however, is not decided.

[[Image:Orange Sea Pen Monterey Bay Aquarium.jpg|thumb|left|Orange Sea Pen (''Ptilosarcus gurneyi'') at [[Monterey Bay Aquarium]], California.]]

[[Category:Anthozoa]]
[[Category:Bioluminescent organisms]]

[[de:Seefedern]]
[[es:Pennatulacea]]
[[fr:Pennatulacea]]
[[it:Pennatulacea]]
[[nl:Pennatulacea]]
[[sk:Perovníky]]
[[fi:Merisulat]]

User:Yoruno

2008-02-19T08:28:16Z

Yoruno:

User:Yoruno

2008-02-11T22:07:49Z

Yoruno: ←Created page with '300px Hi folks! If you want to contact me, please use my '''italian talk page'''....'

[[Image:Grotta della Colombara Portofino.jpg|300px]]

Hi folks!

If you want to contact me, please use my '''[[:it:Discussioni utente:Yoruno|italian talk page]]'''.

Ciao!

[[it:Utente:Yoruno]]