View source for Pliosauroidea

{{Short description|Extinct clade of reptiles}}
{{Automatic taxobox
| name = Pliosauroids
| fossil_range = {{Fossil range|Hettangian|Turonian}}
| image = NHMUK PV R 34 Rhomaleosaurus cramptoni Holotype mod.jpg
| image_caption = Cast of ''[[Rhomaleosaurus cramptoni]]'' (NHMUK PV R 34), Natural History Museum, London
| image2 = Liopleurodon ferox Tubingen 2.JPG
| image2_caption = ''[[Liopleurodon ferox]]'' mounted skeleton, Museum of Paleontology, [[Tübingen]]
| taxon = Pliosauroidea
| authority = [[Samuel Paul Welles|Welles]], 1943
| subdivision_ranks = Families and genera
| subdivision = see text
}}

'''Pliosauroidea''' is an [[extinct]] [[clade]] of [[plesiosaurs]], known from the earliest [[Jurassic]] to early Late [[Cretaceous]]. They are best known for the subclade [[Thalassophonea]], which contained [[crocodile]]-like short-necked forms with large heads and massive toothed jaws, commonly known as '''pliosaurs'''. More primitive non-thalassophonean pliosauroids resembled plesiosaurs in possessing relatively long necks and smaller heads. They originally included only members of the family [[Pliosauridae]], of the order [[Plesiosauria]], but several other genera and families are now also included, the number and details of which vary according to the classification used.

The distinguishing characteristics are a short neck and an elongated head, with larger hind [[flipper (anatomy)|flippers]] compared to the fore flippers, the opposite of the plesiosaurs. They were [[Carnivore|carnivorous]] and their long and powerful jaws carried many sharp, conical teeth. Pliosaurs range from 4 to 10 meters or more in length.<ref>[http://www.zoomdinosaurs.com/subjects/dinosaurs/glossary/indexp3.shtml#Pliosaur zoom dinosaurs]</ref><ref>[http://news.bbc.co.uk/2/hi/science/nature/7264856.stm Sea reptile is biggest on record]. BBC News, February 27, 2008.</ref> Their prey may have included [[fish]], [[sharks]], [[ichthyosaur]]s, [[dinosaur]]s and other plesiosaurs.

The largest known species are ''[[Kronosaurus]]'' and ''[[Pliosaurus macromerus]]''; other well known genera include ''[[Rhomaleosaurus]]'', ''[[Peloneustes]]'', and ''[[Macroplata]]''.<ref name=P.funkei>{{cite journal |author1=Espen M. Knutsen |author2=Patrick S. Druckenmiller |author3=[[Jørn Hurum|Jørn H. Hurum]] |year=2012 |title=A new species of Pliosaurus (Sauropterygia: Plesiosauria) from the Middle Volgian of central Spitsbergen, Norway |journal=Norwegian Journal of Geology |volume=92 |issue=2–3 |pages=235–258 |issn=0029-196X}} [http://www.geologi.no/data/f/0/21/02/6_2401_0/NJG_2_3_2012_13_Knutsen_etal_Scr.pdf Low resolusion pdf] {{webarchive|url=https://web.archive.org/web/20121202090559/http://www.geologi.no/data/f/0/21/02/6_2401_0/NJG_2_3_2012_13_Knutsen_etal_Scr.pdf |date=2012-12-02 }} [http://www.geologi.no/data/f/0/21/02/6_2401_0/NJG_2_3_2012_13_Knutsen_etal_Pr.pdf High resolusion pdf]{{dead link|date=April 2018|bot=medic}}{{cbignore|bot=medic}}</ref> Fossil specimens have been found in [[Africa]], [[Australia]], [[China]], [[Europe]], [[North America]] and [[South America]].

Many very early (from the [[Early Jurassic]] and possibly Latest [[Triassic]], i.e. [[Rhaetian]]) primitive pliosauroids were very like [[plesiosauroid]]s in appearance and, indeed, used to be included in the family [[Plesiosauridae]].

==Name==

[[Image:Liopleurodon ferox 2.jpg|thumb|''Liopleurodon ferox'']]
Pliosauroidea was named by [[Samuel Paul Welles|Welles]] in 1943. It is adapted from the name of the genus ''[[Pliosaurus]]'', which is derived from the [[Ancient Greek|Greek]] {{lang|grc|πλειων}} ({{Transliteration|grc|pleion}}), meaning "more/closely", and {{lang|grc|σαυρος}} ({{Transliteration|grc|sauros}}) meaning "lizard"; it therefore means "more [[sauria]]n". The name ''Pliosaurus'' was coined in 1841 by [[Richard Owen]], who believed that it represented a link between plesiosauroids and [[crocodilian]]s (considered a type of "saurian"), particularly due to their crocodile-like teeth.


==Classification==

===Taxonomy===
[[Image:Macroplata BW.jpg|thumb|right|''[[Macroplata]]'']]
[[File:Pliosaurus restoration 2019.jpg|thumb|''[[Pliosaurus]]'']]
[[Image:Simolestes1DB.jpg|thumb|right|''[[Simolestes|Simolestes vorax]]'']]
[[Image:Attenborosaurus BW.jpg|thumb|right|''[[Attenborosaurus]]'']]
The taxonomy presented here is mainly based on the plesiosaur cladistic analysis proposed by Hilary F. Ketchum and Roger B. J. Benson, 2011 unless otherwise noted.<ref name=Marmornectes>{{cite journal |year=2011 |title=A new pliosaurid (Sauropterygia, Plesiosauria) from the Oxford Clay Formation (Middle Jurassic, Callovian) of England: evidence for a gracile, longirostrine grade of Early-Middle Jurassic pliosaurids |journal=Special Papers in Palaeontology |volume=86 |pages=109–129 |author=Hilary F. Ketchum and Roger B. J. Benson }}</ref>

*Suborder '''Pliosauroidea'''
** ''[[Eurysaurus]]''?
** ''[[Sinopliosaurus]]''?
**Family '''[[Rhomaleosauridae]]'''
*** ''[[Archaeonectrus]]''
*** ''[[Bishanopliosaurus]]''?
*** ''[[Borealonectes]]''<ref name=SW08>{{cite journal |last=Sato |first=Tamaki |author2=Xiao-Chun Wu  |year=2008 |title=A new Jurassic pliosaur from Melville Island, Canadian Arctic Archipelago |journal=Canadian Journal of Earth Sciences |volume=45 |issue=3 |pages=303–320 |doi=10.1139/E08-003 |bibcode=2008CaJES..45..303S |hdl=2309/95302 |hdl-access=free }}</ref>
*** ''[[Eurycleidus]]''
*** ''[[Macroplata]]''
*** ''[[Maresaurus]]''
*** ''[[Meyerasaurus]]''
*** ''[[Rhomaleosaurus]]''
*** ''[[Sthenarosaurus]]''<ref name=SmithDyke08>{{Cite journal |author=Adam S. Smith and Gareth J. Dyke |year=2008 |title=The skull of the giant predatory pliosaur ''Rhomaleosaurus cramptoni'': implications for plesiosaur phylogenetics |url=http://www.plesiosauria.com/pdf/smith&dyke_2008.pdf |journal=Naturwissenschaften |volume=95 |issue= 10|pages=975–980 |doi=10.1007/s00114-008-0402-z |pmid=18523747 |bibcode=2008NW.....95..975S |s2cid=12528732 }}</ref>
*** ''[[Yuzhoupliosaurus]]''?
**Family '''[[Pliosauridae]]'''
*** ''[[Anguanax]]''
*** ''[[Attenborosaurus]]''
*** ''[[Eardasaurus]]''
*** ''[[Gallardosaurus]]''<ref name="Zulma Gasparini">{{cite journal |last=Gasparini |first=Zulma |year=2009 |title=A New Oxfordian Pliosaurid (Plesiosauria, Pliosauridae) in the Caribbean Seaway |url=http://www.redciencia.cu/cdorigen/arca/paper/plio2009.pdf |journal=Palaeontology |volume=52 |issue=3 |pages=661–669 |doi=10.1111/j.1475-4983.2009.00871.x |bibcode=2009Palgy..52..661G |s2cid=55353949 |url-status=dead |archive-url=https://web.archive.org/web/20110716060129/http://www.redciencia.cu/cdorigen/arca/paper/plio2009.pdf |archive-date=2011-07-16 }}</ref>
*** ''[[Hauffiosaurus]]''
*** ''[[Liopleurodon]]''
*** ''[[Marmornectes]]''
*** ''[[Megalneusaurus]]'' 
*** ''[[Pachycostasaurus]]''
*** ''[[Peloneustes]]''
*** ''[[Pliosaurus]]'' 
*** ''[[Rhaeticosaurus]]''
*** ''[[Simolestes]]''
*** ''[[Thalassiodracon]]''
***Subfamily '''Brachaucheninae'''
**** ''[[Brachauchenius]]''
**** ''[[Kronosaurus]]''
**** ''[[Luskhan]]''
**** ''[[Makhaira rossica|Makhaira]]''
**** ''[[Megacephalosaurus]]''
**** ''[[Monquirasaurus]]''
**** ''[[Polyptychodon]]''
**** ''[[Sachicasaurus]]'' 
**** ''[[Stenorhynchosaurus]]''

===Phylogeny===
[[Image:Macrocephalus.jpg|thumb|Cast of ''"Plesiosaurus" macrocephalus'' found by Mary Anning, [[Muséum national d'histoire naturelle]], Paris]]
Pliosauroidea is a [[stem-based taxon]] that was defined by [[Samuel Paul Welles|Welles]] as "all taxa more closely related to ''[[Pliosaurus brachydeirus]]'' than to ''[[Plesiosaurus dolichodeirus]]''". Pliosauridae and Rhomaleosauridae are stem-based taxa too. Pliosauridae is defined as "all taxa more closely related to ''Pliosaurus brachydeirus'' than to ''[[Leptocleidus superstes]]'', ''[[Polycotylus latipinnis]]'' or ''[[Meyerasaurus victor]]''". Rhomaleosauridae is defined as "all taxa more closely related to ''Meyerasaurus victor'' than to ''Leptocleidus superstes'', ''Pliosaurus brachydeirus'' or ''Polycotylus latipinnis''".<ref name="Ketchum2010">{{cite journal |last1=Ketchum |first1=H.F. |last2=Benson |first2=R.B.J. |year=2010 |title=Global interrelationships of Plesiosauria (Reptilia, Sauropterygia) and the pivotal role of taxon sampling in determining the outcome of phylogenetic analyses |journal= Biological Reviews of the Cambridge Philosophical Society |volume=85 |issue=2 |pages=361–392 |doi=10.1111/j.1469-185X.2009.00107.x |pmid=20002391|s2cid=12193439 }}</ref> The [[cladogram]] below follows a 2011 analysis by paleontologists Hilary F. Ketchum and Roger B. J. Benson, and reduced to genera only.<ref name=Marmornectes/>

{{clade| style=font-size:85%;line-height:85%
|label1=Pliosauroidea
|1={{clade
   |label1=[[Rhomaleosauridae]]
   |1={{clade
      |1=''[[Anningasaura]]''
      |2={{clade
         |1={{clade
            |1=''"[[Plesiosaurus]]" macrocephalus''
            |2={{clade
               |1=''[[Archaeonectrus]]''
               |2=''[[Macroplata]]'' }} }}
         |2={{clade
            |1=''[[Atychodracon]]''
            |2={{clade
               |1=''[[Eurycleidus]]''
               |2={{clade
                  |1=''[[Rhomaleosaurus]]''
                  |2={{clade
                     |1=''[[Meyerasaurus]]''
                     |2=''[[Maresaurus]]'' }} }} }} }} }} }}
   |label2=[[Pliosauridae]]
   |2={{clade
      |1=''[[Thalassiodracon]]''
      |2={{clade
         |1=''[[Hauffiosaurus]]''
         |2={{clade
            |1=''[[Attenborosaurus]]''
            |2={{clade
               |1={{clade
                  |1=BMNH R2439
                  |2=''[[Marmornectes]]'' }}
               |2={{clade
                  |1=''"[[Pliosaurus]]" andrewsi''
                  |2={{clade
                     |1={{clade
                        |1=OUMNH J.02247
                        |2=''[[Peloneustes]]'' }}
                     |2={{clade
                        |1=''[[Simolestes]]''
                        |2={{clade
                           |1=''[[Liopleurodon]]''
                           |2={{clade
                              |1=''[[Pliosaurus]]''
                              |2={{clade
                                 |1=''[[Megacephalosaurus]]''<ref name=Megacephalosaurus>{{Cite journal | last1 = Schumacher | first1 = B. A. | last2 = Carpenter | first2 = K. | last3 = Everhart | first3 = M. J. | doi = 10.1080/02724634.2013.722576 | title = A new Cretaceous Pliosaurid (Reptilia, Plesiosauria) from the Carlile Shale (middle Turonian) of Russell County, Kansas | journal = Journal of Vertebrate Paleontology | volume = 33 | issue = 3 | pages = 613–628 | year = 2013 | bibcode = 2013JVPal..33..613S | s2cid = 130165209 }}</ref>
                                 |2={{clade
                                    |1=''[[Brachauchenius]]''
                                    |2=''[[Kronosaurus]]'' }} }} }} }} }} }} }} }} }} }} }} }} }}

==Large pliosauroids==
In 2002, the discovery of a very large pliosauroid was announced in [[Mexico]]. This pliosauroid came to be known as the "[[Monster of Aramberri]]". Although widely reported as such, it does not belong to the genus ''Liopleurodon''.<ref name="L">{{cite web |url=http://www.plesiosaur.com/plesiosaurs/liopleurodon.php |title=The Plesiosaur Site - Liopleurodon |access-date=2017-09-18 |url-status=dead |archive-url=https://web.archive.org/web/20110715093428/http://www.plesiosaur.com/plesiosaurs/liopleurodon.php |archive-date=2011-07-15 }}</ref> The remains of this animal, consisting of a partial vertebral column, were dated to the [[Kimmeridgian]] of the La Caja Formation.<ref>M.-C. Buchy, E. Frey, W. Stinnesbeck, J.-G. Lopez-Oliva (2003) "First occurrence of a gigantic pliosaurid plesiosaur in the late Jurassic (Kimmeridgian) of Mexico", Bull. Soc. geol. Fr., 174(3), pp. 271–278</ref> The fossils were found much earlier, in 1985, by a geology student and were at first erroneously attributed to a [[theropod]] [[dinosaur]] by Hahnel.<ref>Hahnel W. (1988) "Hallazgo de restos de dinosaurio en Aramberri, N.L.,
Mexico", Actas Fac. Cienc. Tierra UANL Linares, 3, 245–250.</ref> The remains originally contained part of a rostrum with teeth (now lost).

In August 2006, palaeontologists of the [[University of Oslo]] discovered the first remains of a pliosaur on Norwegian soil. The remains were described as "very well preserved, as well as being unique in their completeness". The large animal was determined to be a new species of ''[[Pliosaurus]]''.<ref name=P.funkei/> In the summer of 2008, the fossil remains of the huge pliosaur were dug up from the permafrost on [[Svalbard]], a Norwegian island close to the [[North Pole]].<ref>[https://web.archive.org/web/20090319022055/http://www.foxnews.com/story/0,2933,509484,00.html?sPage=fnc/scitech/evolution Fox News: Predator X Was Most Fearsome Animal to Swim Oceans]</ref> The excavation of the find is documented in the 2009 [[History (U.S. TV channel)|History]] television special [[Predator X (TV program)|Predator X]].

{{confusing|date=February 2017}}
On 26 October 2009, palaeontologists reported the discovery of potentially the largest pliosauroid yet found. Found in cliffs near [[Weymouth, Dorset|Weymouth]], [[Dorset]], on Britain's [[Jurassic Coast]], the fossil had a skull length of {{convert|6|ft|5|in|m|abbr=off|sp=us}}. Palaeontologist Richard Forrest told the BBC: "I had heard rumours that something big was turning up. But seeing this thing in the flesh, so to speak, is just jaw dropping. It is simply enormous."<ref>{{cite news| url=http://news.bbc.co.uk/1/hi/sci/tech/8322629.stm| work=BBC News | first=Rebecca | last=Morelle | author-link=Rebecca Morelle | title=Colossal 'sea monster' unearthed | date=27 October 2009}}</ref> It was determined that the specimen belonged to a new species that scientists named ''Pliosaurus kevani''.<ref>{{cite journal |title=A Giant Pliosaurid Skull from the Late Jurassic of England|date = 2013-05-13|author=Benson, Roger J. B.|author2=Evans, Mark|author3=Smith, Adam S.|author4=Sassoon, Judyth|author5=Moore-Faye, Scott|author6=Ketchum, Hilary F.|author7=Forrest, Richard|journal=PLOS ONE|doi=10.1371/journal.pone.0065989 |pmc=3669260|pmid=23741520|volume=8|issue=5|page=e65989|bibcode = 2013PLoSO...865989B|doi-access = free}}</ref>

In December 2023, the recent discovery of a pliosaur skull on the Dorset coast was described as "one of the most complete specimens of its type ever discovered".<ref>{{Cite news |date=2023-12-10 |title=Pliosaur discovery: Huge sea monster emerges from Dorset cliffs |language=en-GB |work=BBC News |url=https://www.bbc.com/news/science-environment-67650247 |access-date=2023-12-10}}</ref> The discovery and research of the skull was covered in the [[PBS]] documentary ''Attenborough and the Jurassic Sea Monster'' hosted by [[David Attenborough]].<ref>{{cite web|url= https://www.pbs.org/wnet/nature/about-attenborough-and-the-jurassic-sea-monster/29745/|title=Attenborough and the Jurassic Sea Monster|date=24 January 2024 |publisher=[[PBS]]|accessdate=24 February 2024}}</ref>

==References==
{{Reflist|30em}}

==External links==
{{Commons category}}
{{Wikispecies}}

* [http://plesiosauria.com/pliosauridae The Plesiosaur Directory - pliosaur page]
* [http://news.bbc.co.uk/earth/hi/earth_news/newsid_8322000/8322629.stm Large pliosaur from the Jurassic Coast, Dorset - BBC News]
* [https://www.bbc.co.uk/news/science-environment-14061347 Dorset pliosaur skull after conservation - video. BBC July 2011]
* [https://www.sciencedaily.com/releases/2017/05/170525125617.htm Fossils News - ScienceDaily: Luskhan Itilensis 2017]

{{Plesiosauria|Pliosauroidea}}
{{Taxonbar|from=Q843192}}

[[Category:Plesiosaurs]]
[[Category:Hettangian first appearances]]
[[Category:Cenomanian extinctions]]