Editing Jurassic (section)

==== Plesiosaurs ====
[[File:Rhomaleosaurus cramptoni (fossil).jpg|thumb|''[[Rhomaleosaurus|Rhomaleosaurus cramptoni]]'' at the Natural History Museum, London]]
[[Plesiosauria|Plesiosaurs]] originated at the end of the Triassic (Rhaetian). By the end of the Triassic, all other [[sauropterygia]]ns, including [[Placodontia|placodonts]] and [[nothosaur]]s, had become extinct. At least six lineages of plesiosaur crossed the Triassic–Jurassic boundary.<ref>{{Cite journal|last1=Wintrich|first1=Tanja|last2=Hayashi|first2=Shoji|last3=Houssaye|first3=Alexandra|last4=Nakajima|first4=Yasuhisa|last5=Sander|first5=P. Martin|date=2017-12-01|title=A Triassic plesiosaurian skeleton and bone histology inform on evolution of a unique body plan|url= |journal=Science Advances|language=en|volume=3|issue=12|pages=e1701144|doi=10.1126/sciadv.1701144|pmid=29242826|pmc=5729018|bibcode=2017SciA....3E1144W|issn=2375-2548}}</ref> Plesiosaurs were already diverse in the earliest Jurassic, with the majority of plesiosaurs in the Hettangian-aged Blue Lias belonging to the [[Rhomaleosauridae]]. Early plesiosaurs were generally small-bodied, with body size increasing into the Toarcian.<ref>{{Cite journal|last1=Benson|first1=Roger B. J.|last2=Evans|first2=Mark|last3=Druckenmiller|first3=Patrick S.|date=2012-03-16|title=High Diversity, Low Disparity and Small Body Size in Plesiosaurs (Reptilia, Sauropterygia) from the Triassic–Jurassic Boundary|journal=PLOS ONE|language=en|volume=7|issue=3|pages=e31838|doi=10.1371/journal.pone.0031838|issn=1932-6203|pmc=3306369|pmid=22438869|bibcode=2012PLoSO...731838B|doi-access=free}}</ref> There appears to have been a strong turnover around the Early–Middle Jurassic boundary, with [[Microcleididae|microcleidids]] and rhomaleosaurids becoming extinct and nearly extinct respectively after the end of the Toarcian with the first appearance of the dominant clade of plesiosaurs of the latter half of the Jurassic, the [[Cryptoclididae]] during the Bajocian.<ref name="Fischer-2021" /> The Middle Jurassic saw the evolution of short-necked and large-headed [[Thalassophonea|thalassophonean pliosaurs]] from ancestrally small-headed, long-necked forms''.''<ref>{{Cite journal|last=O'Keefe|first=F. Robin|date=2002|title=The evolution of plesiosaur and pliosaur morphotypes in the Plesiosauria (Reptilia: Sauropterygia)|url=https://www.cambridge.org/core/journals/paleobiology/article/abs/evolution-of-plesiosaur-and-pliosaur-morphotypes-in-the-plesiosauria-reptilia-sauropterygia/8A68F79F7BCF0D56D2D7435D3A018704|journal=Paleobiology|language=en|volume=28|issue=1|pages=101–112|doi=10.1666/0094-8373(2002)028<0101:TEOPAP>2.0.CO;2|bibcode=2002Pbio...28..101O |s2cid=85753943 |issn=0094-8373}}</ref><ref name="Fischer-2021" /> Some thalassophonean pliosaurs, such as some species of ''[[Pliosaurus]]'', had skulls up to two metres in length with body lengths estimated around {{convert|10|–|12|m|ft|sp=us}}, making them the apex predators of Late Jurassic oceans.<ref>{{Cite journal|last1=Benson|first1=Roger B. J.|last2=Evans|first2=Mark|last3=Smith|first3=Adam S.|last4=Sassoon|first4=Judyth|last5=Moore-Faye|first5=Scott|last6=Ketchum|first6=Hilary F.|last7=Forrest|first7=Richard|date=2013-05-31|title=A Giant Pliosaurid Skull from the Late Jurassic of England|journal=PLOS ONE|language=en|volume=8|issue=5|pages=e65989|doi=10.1371/journal.pone.0065989|issn=1932-6203|pmc=3669260|pmid=23741520|bibcode=2013PLoSO...865989B|doi-access=free}}</ref><ref name="Fischer-2021" /> Plesiosaurs invaded freshwater environments during the Jurassic, with indeterminate remains of small-bodied pleisosaurs known from freshwater sediments from the Jurassic of China and Australia.<ref>{{Cite journal|last1=Gao|first1=Ting|last2=Li|first2=Da-Qing|last3=Li|first3=Long-Feng|last4=Yang|first4=Jing-Tao|date=2019-08-13|title=The first record of freshwater plesiosaurian from the Middle Jurassic of Gansu, NW China, with its implications to the local palaeobiogeography|journal=Journal of Palaeogeography|volume=8|issue=1|pages=27|doi=10.1186/s42501-019-0043-5|bibcode=2019JPalG...8...27G|s2cid=199547716|issn=2524-4507|doi-access=free}}</ref><ref>{{Cite journal|last=Kear|first=Benjamin P.|date=2 August 2012|title=A revision of Australia's Jurassic plesiosaurs |journal=Palaeontology|language=en|volume=55|issue=5|pages=1125–1138|doi=10.1111/j.1475-4983.2012.01183.x|bibcode=2012Palgy..55.1125K |doi-access=free}}</ref>