View source for Biology:Cassiopea

{{Short description|Genus of jellyfishes}}
{{Automatic taxobox
| image = fkeysmacro.jpg
| image_caption = ''Cassiopea sp.''
| parent_authority = Agassiz, 1862
| taxon = Cassiopea
| authority = Péron & Lesueur, 1809
| subdivision_ranks = [[Biology:Species|Species]]
| subdivision = 8 species, see text
| synonyms = {{Species list
  |Cassiopeia|Gistl, 1848<ref>IRMNG (2021). [https://www.irmng.org/aphia.php?p=taxdetails&id=1443660 ''Cassiopeia'' Gistl, 1848]. Accessed on 2023-05-29.</ref>
  |Cassiopeja|Schultze, 1898<ref>IRMNG (2021). [https://irmng.org/aphia.php?p=taxdetails&id=1318496 ''Cassiopeja'' Schultze, 1898]. Accessed on 2023-05-29.</ref>
  }} 
}}

[[File:Upside-Down Jelly fish.JPG|thumbnail|alt=several white frondy creatures amongst strands of bright green seaweed|''Cassiopea sp.'' in [[Biology:Seaweed|seaweed]].]]

'''''Cassiopea''''' ('''upside-down jellyfish''') is a [[Biology:Genus|genus]] of [[Biology:Scyphozoa|true jellyfish]] and the only members of the family '''Cassiopeidae'''.<ref>{{WoRMS |id=135234 |title=Cassiopeidae |accessdate=3 August 2012}}</ref> They are found in warmer coastal regions around the world, including shallow [[Earth:Mangrove|mangrove]] swamps, mudflats, canals, and turtle grass flats in Florida, and the Caribbean and [[Place:Micronesia|Micronesia]]. The medusa usually lives upside-down on the bottom, which has earned them the common name. These jellyfish partake in a symbiotic relationship with photosynthetic [[Biology:Dinoflagellate|dinoflagellate]]s and therefore, must lie upside-down in areas with sufficient light penetration to fuel their energy source.<ref>{{cite journal |author=Ohdera Aki H. |author2=Abrams Michael J. |author3=Ames Cheryl L. |author4=Baker David M. |author5=Suescún-Bolívar Luis P. |author6=Collins Allen G. |author7=Freeman Christopher J. |author8=Gamero-Mora Edgar |author9=Goulet Tamar L. |author10=Hofmann Dietrich K. |author11=Jaimes-Becerra Adrian |author12=Long Paul F. |author13=Marques Antonio C. |author14=Miller Laura A. |author15=Mydlarz Laura D. |author16=Morandini Andre C. |author17=Newkirk Casandra R. |author18=Putri Sastia P. |author19=Samson Julia E. |author20=Stampar Sérgio N. |author21=Steinworth Bailey |author22=Templeman Michelle |author23=Thomé Patricia E. |author24=Vlok Marli |author25=Woodley Cheryl M. |author26=Wong Jane C.Y. |author27=Martindale Mark Q. |author28=Fitt William K. |author29=Medina Mónica |title=Upside-Down but Headed in the Right Direction: Review of the Highly Versatile Cassiopea xamachana System |journal=Frontiers in Ecology and Evolution |volume=6 |year=2018|page=35 |doi=10.3389/fevo.2018.00035|doi-access=free |hdl=11449/176281 |hdl-access=free }}</ref> Where found, there may be numerous individuals with varying shades of white, blue, green and brown.

== Species ==
According to the ''[[Organization:World Register of Marine Species|World Register of Marine Species]]'', this genus includes 8 species:<ref name=WoRMS>{{WoRMS |id=135253 |title=Cassiopea |accessdate=3 August 2012}}</ref>

* ''[[Biology:Cassiopea andromeda|Cassiopea andromeda]]'' <small>(Forsskål, 1775)—Indo-Pacific, introduced in the Mediterranean</small>
* ''Cassiopea depressa'' <small> Haeckel, 1880—Western Indian Ocean off the African coast</small>
* ''Cassiopea frondosa'' <small>(Pallas, 1774)—Western Atlantic, Caribbean Sea</small>
* ''Cassiopea maremetens'' <small>Gershwin, Zeidler & Davie, 2010—Western Pacific Ocean, off the Australian Coast</small>
* ''Cassiopea medusa'' <small>Light, 1914—Pacific Ocean, Philippines and Palau Region</small>
* ''Cassiopea mertensi'' <small>Brandt, 1838—Pacific Ocean Southern Micronesia</small>
* ''[[Biology:Cassiopea ndrosia|Cassiopea ndrosia]]'' <small>Agassiz & Mayer, 1899—Pacific Ocean, Australia and Fiji</small>
* ''[[Biology:Cassiopea ornata|Cassiopea ornata]]'' <small>Haeckel, 1880—Pacific Ocean, Palau, Philippines, Okinawa</small>
* ''[[Biology:Cassiopea xamachana|Cassiopea xamachana]]'' <small>Bigelow, 1892—Caribbean Sea and the Northern Atlantic Area of the West indies</small>

== Defense system ==
''Cassiopea'' species have a mild sting since they are primarily photosynthetic, but sensitive individuals may have a stronger reaction. The photosynthesis occurs because, like most [[Biology:Coral|coral]]s, they host [[Biology:Zooxanthellae|zooxanthellae]] in their tissues.<ref>{{cite book |last=Murphy |first=Richard C. |title=Coral Reefs: Cities Under The Sea |year=2002 |publisher=The Darwin Press |location=Princeton, New Jersey |isbn=978-0-87850-138-0 }}</ref> The stinging cells are also found in cellular masses, dubbed "cassiosomes", excreted in a [[Biology:Mucus|mucus]]; people swimming near the jellyfish may come in contact with these cassiosomes and be stung.<ref>{{Cite journal|last1=Ames|first1=Cheryl L.|last2=Klompen|first2=Anna M. L.|last3=Badhiwala|first3=Krishna|last4=Muffett|first4=Kade|last5=Reft|first5=Abigail J.|last6=Kumar|first6=Mehr|last7=Janssen|first7=Jennie D.|last8=Schultzhaus|first8=Janna N.|last9=Field|first9=Lauren D.|last10=Muroski|first10=Megan E.|last11=Bezio|first11=Nick|date=2020-02-13|title=Cassiosomes are stinging-cell structures in the mucus of the upside-down jellyfish Cassiopea xamachana|journal=Communications Biology|language=en|volume=3|issue=1|pages=67|doi=10.1038/s42003-020-0777-8|pmid=32054971|pmc=7018847|issn=2399-3642}}</ref><ref>{{cite news |title=Stinging water mystery solved: Jellyfish can sting swimmers, prey with 'mucus grenades' |url=https://phys.org/news/2020-02-mystery-jellyfish-swimmers-prey-mucus.html |publisher=Phys.org |date=February 13, 2020 |access-date=February 14, 2020}}</ref> The stings, appearing in the form of a red rash-like skin irritation, are known for being extraordinarily itchy. Sometimes this jellyfish is picked up by the [[Biology:Crab|crab]] ''[[Biology:Dorippe frascone|Dorippe frascone]]'' and carried on its back{{Citation needed|date=August 2022}}. The crab uses the jellyfish to defend itself against possible predators.

==Behavior==
Certain species of ''Cassiopea'' have been observed to enter a [[Biology:Sleep|sleep state]] - exhibiting decreased pulsation rate, reduced responsiveness to stimuli, and compensatory rebound sleep after deprivation.<ref>{{cite web|title=The surprising, ancient behavior of jellyfish|url=https://www.eurekalert.org/pub_releases/2017-09/ciot-tsa091517.php#.WcUvtLr_O5M.reddit|website=EurekAlert|access-date=22 September 2017}}</ref> They are the first animals with no central nervous system to have been observed sleeping.<ref>{{Cite web |first= |date=2017 |title=The Jellyfish Cassiopea Exhibits a Sleep-like State |url=https://pubmed.ncbi.nlm.nih.gov/28943083/ |website=Current biology}}</ref>

[[File:Cassiopea map.png|thumb|Cassiopea Species Distribution Map]]

==References==
{{Reflist}}

== External links ==
{{Commons}}
* [http://www.starfish.ch/c-invertebrates/hydroids.html#Cassiopeidae Photo of a Crab carrying an Upside Down Jellyfish (Cassiopea andromeda)]
* [http://www2.bishopmuseum.org/HBS/invertguide/species/cassiopea_andromeda.htm Bernice Pauahi Bishop Museum entry on ''Cassiopea andromeda'']
* [http://jrscience.wcp.muohio.edu/fieldcourses05/PapersMarineEcologyArticles/ASymbioticLifestyle.C.xam.html A Symbiotic Lifestyle: C. xamachana and Zooxanthellae]

{{Taxonbar|from=Q289354}}

[[Category:Cassiopea| ]]
[[Category:Cassiopeidae]]

{{Sourceattribution|Cassiopea}}