Editing Cretaceous (section)

==Marine fauna==
In the seas, [[batoidea|rays]], modern [[shark]]s and [[teleost]]s became common.<ref>{{cite web|url=http://www.talkorigins.org/origins/geo_timeline.html|title=EVOLUTIONARY/GEOLOGICAL TIMELINE v1.0|website=www.TalkOrigins.org|access-date=18 October 2017}}</ref> Marine reptiles included [[ichthyosaur]]s in the early and mid-Cretaceous (becoming extinct during the late Cretaceous [[Cenomanian-Turonian anoxic event]]), [[plesiosaur]]s throughout the entire period, and [[mosasaur]]s appearing in the Late Cretaceous. Sea turtles in the form of [[Cheloniidae]] and [[Panchelonioidea]] lived during the period and survived the extinction event. Panchelonioidea is today represented by a single species; the [[leatherback sea turtle]]. The [[Hesperornithiformes]] were flightless, marine diving birds that swam like [[grebe]]s.

''[[Baculites]]'', an [[ammonite]] genus with a straight shell, flourished in the seas along with reef-building [[rudist]] clams. [[Inoceramidae|Inoceramids]] were also particularly notable among Cretaceous bivalves,<ref>{{Cite journal |last1=Walaszczyk |first1=I. |last2=Szasz |first2=L. |date=1 December 1997 |title=Inoceramid bivalves from the Turonian/Coniacian (Cretaceous) boundary in Romania: revisions of Simonescu's (1899) material from Ürmös (Ormenis), Transylvania |url=https://www.sciencedirect.com/science/article/pii/S0195667197900860 |journal=[[Cretaceous Research]] |volume=18 |issue=6 |pages=767–787 |doi=10.1006/cres.1997.0086 |bibcode=1997CrRes..18..767W |issn=0195-6671 |access-date=24 November 2023}}</ref> and they have been used to identify major biotic turnovers such as at the Turonian-Coniacian boundary.<ref>{{Cite journal |last1=Wood |first1=Christopher J. |last2=Ernst |first2=Gundolf |last3=Rasemann |first3=Gabriele |date=11 September 1984 |title=The Turonian-Coniacian stage boundary in Lower Saxony (Germany) and adjacent areas: the Salzgitter-Salder Quarry as a proposed international standard section |url=https://2dgf.dk/xpdf/bull33-01-02-225-238.pdf |journal=Bulletin of the Geological Society of Denmark |language=en |volume=33 |pages=225–238 |doi=10.37570/bgsd-1984-33-21 |issn=2245-7070}}</ref><ref>{{cite journal |last1=Walaszczyk |first1=Ireneusz Piotr |last2=Cobban |first2=W. A. |date=January 1998 |title=The Turonian - Coniacian boundary in the United States Western interior |url=https://www.researchgate.net/publication/287488582 |journal=[[Acta Geologica Polonica]] |volume=48 |issue=4 |pages=495–507 |access-date=24 November 2023}}</ref> Predatory gastropods with drilling habits were widespread.<ref>{{Cite journal |last=Kosnik |first=Matthew A. |date=1 September 2005 |title=Changes in Late Cretaceous–early Tertiary benthic marine assemblages: analyses from the North American coastal plain shallow shelf |url=https://bioone.org/journals/paleobiology/volume-31/issue-3/0094-8373_2005_031_0459_CILCTB_2.0.CO_2/Changes-in-Late-Cretaceousearly-Tertiary-benthic-marine-assemblages--analyses/10.1666/0094-8373(2005)031[0459:CILCTB]2.0.CO;2.short |journal=[[Paleobiology (journal)|Paleobiology]] |language=en |volume=31 |issue=3 |pages=459–479 |doi=10.1666/0094-8373(2005)031[0459:CILCTB]2.0.CO;2 |s2cid=130932162 |issn=0094-8373 |access-date=22 September 2023}}</ref> Globotruncanid [[foraminifera]] and [[echinoderms]] such as sea urchins and [[Asteroidea|starfish (sea stars)]] thrived. [[Ostracods]] were abundant in Cretaceous marine settings; ostracod species characterised by high male sexual investment had the highest rates of extinction and turnover.<ref>{{cite journal |last1=Fernandes Martins |first1=Maria João |last2=Puckett |first2=Mark |last3=Lockwood |first3=Rowan |last4=Swaddle |first4=John P. |last5=Hunt |first5=Gene |date=11 April 2018 |title=High male sexual investment as a driver of extinction in fossil ostracods |url=https://www.researchgate.net/publication/324504488 |journal=[[Nature (journal)|Nature]] |volume=556 |issue=7701 |pages=366–369 |doi=10.1038/s41586-018-0020-7 |pmid=29643505 |bibcode=2018Natur.556..366M |s2cid=256767945 |access-date=31 March 2023}}</ref> [[Thylacocephala]], a class of crustaceans, went extinct in the Late Cretaceous. The first radiation of the [[diatom]]s (generally [[silicon dioxide|siliceous]] shelled, rather than [[calcareous]]) in the oceans occurred during the Cretaceous; freshwater diatoms did not appear until the [[Miocene]].<ref name="UCMP">{{cite web|url=http://www.ucmp.berkeley.edu/mesozoic/cretaceous/cretlife.html|title=Life of the Cretaceous|website=www.ucmp.Berkeley.edu|access-date=18 October 2017}}</ref> Calcareous nannoplankton were important components of the marine microbiota and important as biostratigraphic markers and recorders of environmental change.<ref>{{Cite journal |last=Lees |first=Jackie A. |date=February 2008 |title=The calcareous nannofossil record across the Late Cretaceous Turonian/Coniacian boundary, including new data from Germany, Poland, the Czech Republic and England |url=https://linkinghub.elsevier.com/retrieve/pii/S0195667107000961 |journal=[[Cretaceous Research]] |language=en |volume=29 |issue=1 |pages=40–64 |doi=10.1016/j.cretres.2007.08.002 |bibcode=2008CrRes..29...40L |access-date=24 November 2023}}</ref>

The Cretaceous was also an important interval in the evolution of [[bioerosion]], the production of borings and scrapings in rocks, [[hardgrounds]] and shells.
<gallery class="center">
File:Kronosaurus hunt1DB.jpg|A scene from the early Cretaceous: a ''[[Woolungasaurus]]'' is attacked by a ''[[Kronosaurus]]''.
File:Tylosaurus pembinensis 1DB.jpg|''[[Tylosaurus]]'' was a large [[mosasaur]], carnivorous marine reptiles that emerged in the late Cretaceous.
File:Hesperornis BW (white background).jpg|Strong-swimming and toothed predatory waterbird ''[[Hesperornis]]'' roamed late Cretacean oceans.
File:DiscoscaphitesirisCretaceous.jpg|The [[ammonite]] ''[[Discoscaphites]] iris'', Owl Creek Formation (Upper Cretaceous), Ripley, Mississippi
File:The fossils from Cretaceous age found in Lebanon.jpg|A plate with ''[[Nematonotus]] sp.'', ''Pseudostacus sp.'' and a partial ''Dercetis triqueter'', found in [[Hakel]], Lebanon
File:Cretoxyrhina attacking Pteranodon.png|''[[Cretoxyrhina]]'', one of the largest Cretaceous [[shark]]s, attacking a ''[[Pteranodon]]'' in the [[Western Interior Seaway]]
</gallery>