Editing Coral (section)

===Early corals===
Corals first appeared in the [[Cambrian]] about {{Ma|535}}.<ref name=Pratt>{{cite book | last1=Pratt | first1=B.R. | last2=Spincer | first2=B.R. | first3=R.A. | last3=Wood | first4=A.Yu. | last4=Zhuravlev | title=Ecology of the Cambrian Radiation | year=2001 | chapter-url=ftp://gis.dipbsf.uninsubria.it/zoo/The%20Ecology%20of%20the%20Cambrian%20Radiation%20-%20Andrey%20Zhuravlev.pdf | access-date=2007-04-06 | publisher=Columbia University Press | isbn=978-0-231-10613-9 | page=259 | chapter=12: Ecology and Evolution of Cambrian Reefs }}{{dead link|date=January 2018 |bot=InternetArchiveBot |fix-attempted=yes }}</ref> [[Fossil]]s are extremely rare until the [[Ordovician]] period, 100 million years later, when Heliolitida, [[Rugosa|rugose]], and [[tabulata|tabulate]] corals became widespread. [[Paleozoic]] corals often contained numerous endobiotic symbionts.<ref name="VinnMotus2008">{{cite journal | doi=10.1666/07-056.1 | title=The earliest endosymbiotic mineralized tubeworms from the Silurian of Podolia, Ukraine | year=2008 | author=Vinn, O. | author2=Mõtus, M.-A. | journal=Journal of Paleontology | volume=82 | issue=2 | pages=409–14 | bibcode=2008JPal...82..409V | s2cid=131651974 | url=https://www.researchgate.net/publication/222089801 | access-date=2014-06-11}}</ref><ref name="VinnMotus2012">{{cite journal | title=Diverse early endobiotic coral symbiont assemblage from the Katian (Late Ordovician) of Baltica | year=2012 | author=Vinn, O. | author2=Mõtus, M.-A. | journal=Palaeogeography, Palaeoclimatology, Palaeoecology | volume=321–322 | pages=137–41 |doi=10.1016/j.palaeo.2012.01.028 | bibcode=2012PPP...321..137V }}</ref>

Tabulate corals occur in [[limestone]]s and calcareous [[shale]]s of the Ordovician period, with a gap in the fossil record due to [[Ordovician–Silurian extinction events|extinction events]] at the end of the Ordovician. Corals reappeared some millions of years later during the [[Silurian]] period, and tabulate corals often form low cushions or branching masses of [[calcite]] alongside rugose corals. Tabulate coral numbers began to decline during the middle of the Silurian period.<ref name=Tabulata>{{cite web |title=Introduction to the Tabulata |url=http://www.ucmp.berkeley.edu/cnidaria/tabulata.html |publisher=UCMP Berkeley |access-date=25 April 2015 |archive-url=https://web.archive.org/web/20150419112928/http://www.ucmp.berkeley.edu/cnidaria/tabulata.html |archive-date=19 April 2015 |url-status=dead }}</ref>

Rugose or horn corals became dominant by the middle of the Silurian period, and during the Devonian, corals flourished with more than 200 genera. The rugose corals existed in solitary and colonial forms, and were also composed of calcite.<ref>{{cite web|title=Introduction to the Rugosa|url=http://www.ucmp.berkeley.edu/cnidaria/rugosa.html|publisher=UCMP Berkeley|access-date=25 April 2015|archive-url=https://web.archive.org/web/20150419112923/http://www.ucmp.berkeley.edu/cnidaria/rugosa.html|archive-date=19 April 2015|url-status=dead}}</ref> Both rugose and tabulate corals became extinct in the [[Permian–Triassic extinction event]]<ref name=Tabulata /><ref>Xiang-Dong Wang and Xiao-Juan Wang (2007). [https://www.sciencedirect.com/science/article/abs/pii/S1871174X07000170 "Extinction patterns of Late Permian (Lopingian) corals in China"], ''Palaeoworld, 16,'' No. 1–3, 31–38</ref> {{Ma|250}} (along with 85% of marine species), and there is a gap of tens of millions of years until new forms of coral evolved in the [[Triassic]].

<gallery mode="packed" heights="150px" style="float:left;">
File:Syringoporid.jpg| Tabulate coral (a syringoporid); Boone limestone (Lower [[Carboniferous]]) near Hiwasse, Arkansas, scale bar is 2.0&nbsp;cm
File:AuloporaDevonianSilicaShale.jpg| Tabulate coral ''[[Aulopora]]'' from the [[Devonian]] period
File:RugosaOrdovician.jpg| Solitary rugose coral (''[[Grewingkia]]'') in three views; Ordovician, southeastern Indiana
</gallery>

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