Editing Demosponge (section)

{{Short description|Class of sponges}}
{{Automatic taxobox
| fossil_range = [[Cambrian Stage 3]] – present, {{fossil range |515|0|earliest=650|ref=<ref>{{Cite journal|last1=Botting|first1=J.P.|last2=Cárdenas|first2=P.|last3=Peel|first3=J.S.|date=January 2015|title=A crown-group demosponge from the early Cambrian Sirius Passet Biota, North Greenland|journal=Palaeontology|volume=58|issue=1|pages=35–43|doi=10.1111/pala.12133|bibcode=2015Palgy..58...35B}}</ref>}}
(Possible [[Neoproterozoic]] record<ref name=Love09/>)
| taxon = Demospongiae
| image = Sponges in Caribbean Sea, Cayman Islands.jpg
| image_caption = Included are the yellow tube sponge, ''[[Aplysina fistularis]]'', the purple vase sponge, ''[[Niphates digitalis]]'', the red encrusting sponge, ''[[Spiratrella coccinea]]'', and the gray rope sponge, ''[[Callyspongia]]'' sp.
| authority = [[William Johnson Sollas|Sollas]], 1885
| subdivision_ranks = Subclasses
| subdivision = * [[Heteroscleromorpha]]
* [[Keratosa]]
* [[Verongimorpha]]
* Order †[[Protomonaxonida]]
}}
[[File:Chondrocladia lampadiglobus.jpg|thumb| The carnivorous ping-pong tree sponge, ''[[Chondrocladia|Chondrocladia lampadiglobus]]'' <ref>{{cite journal |first=J. |last=Vacelet |title=New carnivorous sponges (Porifera, Poecilosclerida) collected from manned submersibles in the deep Pacific |journal=Zoological Journal of the Linnean Society |volume=148 |pages=553–584. Figure 17 |date=2006 |issue=4 |doi=10.1111/j.1096-3642.2006.00234.x }}</ref><ref>{{Cite journal|doi = 10.1371/journal.pone.0035105|title = Global Diversity of Sponges (Porifera)|year = 2012|last1 = Van Soest|first1 = Rob W. M.|last2 = Boury-Esnault|first2 = Nicole|last3 = Vacelet|first3 = Jean|last4 = Dohrmann|first4 = Martin|last5 = Erpenbeck|first5 = Dirk|last6 = De Voogd|first6 = Nicole J.|last7 = Santodomingo|first7 = Nadiezhda|last8 = Vanhoorne|first8 = Bart|last9 = Kelly|first9 = Michelle |author-link9=Michelle Kelly (marine scientist)|last10 = Hooper|first10 = John N. A.|journal = PLOS ONE|volume = 7|issue = 4|pages = e35105|pmid = 22558119|pmc = 3338747|bibcode = 2012PLoSO...735105V|doi-access = free}}</ref>]]
[[File:Monanchora arbuscula (Red encrusting sponge).jpg|thumb|''[[Monanchora arbuscula]]'' ([[Poecilosclerida]])]]
[[File:Geodia barretti.jpg|thumb|''[[Geodia barretti]]'' ([[Tetractinellida]])]]
[[File:Chondrosia reniformis01.jpg|thumb|''[[Chondrosia reniformis]]'' ([[Chondrosiida]])]]
[[File:Spongia officinalis.jpg|thumb|''[[Spongia officinalis]]'' ([[Dictyoceratida]])]]
[[File:Spongilla lacustris.jpg|thumb|''[[Spongilla lacustris]]'' ([[Spongillida]])]]

'''Demosponges''' or '''common sponges''' are [[sponge]]s of the [[class (biology)|class]] '''Demospongiae''' (from {{langx|grc|δῆμος|dêmos|common people}} + {{langx|grc|σπογγιά|spongiá|sponge|label=none}}), the most diverse group in the [[phylum]] [[Porifera]] which include greater than 90% of all [[extant taxon|extant]] sponges with nearly 8,800 [[species]] worldwide (according to the World Porifera Database).<ref>{{cite web|url=http://www.marinespecies.org/porifera/|title=World Porifera Database|work=marinespecies.org|access-date=21 October 2015}}</ref> Being [[siliceous sponge]]s, they are predominantly [[sponge#leuconoid|leuconoid]] in structure with an [[endoskeleton]] made of a meshwork of [[sponge spicule|spicule]]s consisting of fibers of the protein [[spongin]], the mineral [[silica]], or both. Where spicules of silica are present, they have a different shape from those in the otherwise similar [[glass sponge]]s.<ref name=IZ>{{cite book |author= Barnes, Robert D. |year=1982 |title= Invertebrate Zoology |publisher= Holt-Saunders International |location= Philadelphia, PA|pages= 105–6|isbn= 978-0-03-056747-6}}</ref> Some species, in particular from the [[Antarctic]], obtain the silica for spicule-building from the ingestion of [[diatoms]].<ref>{{cite journal|first1=Ana|last1=Riesgo|first2=Sergi|last2=Taboada|first3=Nathan J.|last3=Kenny|first4=Nadia|last4= Santodomingo|first5=Juan|last5=Moles|first6=Carlos|last6=Leiva|first7=Eileen|last7=Cox|first8=Conxita|last8=Avila|first9=Luis|last9=Cardona|first10=Manuel|last10=Maldonado|title=Recycling resources: silica of diatom frustules as a source for spicule building in Antarctic siliceous demosponges.|journal= Zoological Journal of the Linnean Society|volume=192|issue=2|year=2021|pages= 259–276|doi=10.1093/zoolinnean/zlaa058}}</ref>

The many diverse [[Order (biology)|orders]] in this class include all of the large sponges. About 311 million years ago, in the [[Pennsylvanian (geology)|Late Carboniferous]], the order [[Spongillida]] split from the marine sponges, and is the only sponges to live in freshwater environments.<ref>{{cite journal |vauthors=Schuster A, Vargas S, Knapp IS, Pomponi SA, Toonen RJ, Erpenbeck D, Wörheide G |title=Divergence times in demosponges (Porifera): first insights from new mitogenomes and the inclusion of fossils in a birth-death clock model |journal=BMC Evol Biol |volume=18 |issue=1 |pages=114 |date=July 2018 |pmid=30021516 |pmc=6052604 |doi=10.1186/s12862-018-1230-1 |doi-access=free|bibcode=2018BMCEE..18..114S }}</ref> Some species are brightly colored, with great variety in body shape; the largest species are over {{convert|1|m|ft|abbr=on}} across.<ref name=IZ/> They reproduce both sexually and [[asexual reproduction|asexually]]. They are the only extant organisms that [[methylate]] [[sterol]]s at the 26-position, a fact used to identify the presence of demosponges before their first known unambiguous fossils.<ref>{{Cite journal|last1=Brocks|first1=J. J.|last2=Jarrett|first2=A. J. M.|last3=Sirantoine|first3=E.|last4=Kenig|first4=F.|last5=Moczydłowska|first5=M.|last6=Porter|first6=S.|last7=Hope|first7=J.|date=2016-03-01|title=Early sponges and toxic protists: possible sources of cryostane, an age diagnostic biomarker antedating Sturtian Snowball Earth|journal=Geobiology|language=en|volume=14|issue=2|pages=129–149|doi=10.1111/gbi.12165|pmid=26507690|bibcode=2016Gbio...14..129B |issn=1472-4669}}</ref><ref name=Love09>{{Cite journal|last1=Love|first1=Gordon D.|last2=Grosjean|first2=Emmanuelle|last3=Stalvies|first3=Charlotte|last4=Fike|first4=David A.|last5=Grotzinger|first5=John P.|last6=Bradley|first6=Alexander S.|last7=Kelly|first7=Amy E.|last8=Bhatia|first8=Maya|last9=Meredith|first9=William|title=Fossil steroids record the appearance of Demospongiae during the Cryogenian period|journal=Nature|volume=457|issue=7230|pages=718–721|doi=10.1038/nature07673|pmid=19194449|year=2009|bibcode=2009Natur.457..718L|s2cid=4314662|url=https://authors.library.caltech.edu/14867/2/Love2009p34510.1038nature07673_supp.pdf|access-date=2019-01-27|archive-url=https://web.archive.org/web/20180724144041/https://authors.library.caltech.edu/14867/2/Love2009p34510.1038nature07673_supp.pdf|archive-date=2018-07-24|url-status=dead}}</ref>

Because of many species' long life span (500–1,000&nbsp;years) it is thought that analysis of the aragonite [[skeleton]]s of these sponges could extend data regarding [[ocean temperature]], [[salinity]], and other variables farther into the past than has been previously possible. Their dense skeletons are deposited in an organized chronological manner, in concentric layers or bands. The layered skeletons look similar to [[reef]] [[coral]]s. Therefore, demosponges are also called '''coralline sponges'''.