Pleurosaurus

{{Short description|Extinct genus of reptiles}} {{Automatic taxobox | fossil_range = Late Jurassic, {{fossilrange|152|150.8}} | image = Pleurosaurus sp. NTM.jpg | image_upright = 1.15 | image_caption = ''P.'' sp., National Taiwan Museum | image2 = Pleurosaurus dorsal.svg | image2_caption = Skull diagram | taxon = Pleurosaurus | authority = Meyer, 1831 | type_species = {{extinct}}'''''Pleurosaurus goldfussi''''' | type_species_authority = Meyer, 1831 | subdivision_ranks = Species | subdivision = *{{extinct}}''P. goldfussi'' <small>Meyer, 1831</small> *{{extinct}}''P. ginsburgi'' <small>Fabre, 1974</small> | synonyms = *{{extinct}}''Acrosaurus frischmanni''? {{small|Von Meyer, 1854}}<ref name="Beccari2024">{{Cite journal |last=Beccari |first=Victor |last2=Villa |first2=Andrea |last3=Jones |first3=Marc E. H. |last4=Ferreira |first4=Gabriel S. |last5=Glaw |first5=Frank |last6=Rauhut |first6=Oliver W. M. |date=2024-07-22 |title=A juvenile pleurosaurid (Lepidosauria: Rhynchocephalia) from the Tithonian of the Mörnsheim Formation, Germany |journal=The Anatomical Record |language=en |volume=308 |issue=3 |pages=844–867 |doi=10.1002/ar.25545 |issn=1932-8486 |pmc=11791384 |pmid=39039747 |doi-access=free}}</ref> }}

'''''Pleurosaurus''''', from Ancient Greek πλευρά (''pleurá''), meaning "rib" or "side", and σαυρος (''sauros''), meaning "lizard", is an extinct genus of aquatic reptiles belonging to the order Rhynchocephalia. ''Pleurosaurus'' fossils have primarily been discovered in the Solnhofen Limestone of Bavaria, Germany and the Canjuers lagerstatte near Canjuers, France, both dating to the Late Jurassic. It contains two species, ''P. goldfussi'' and ''P. ginsburgi''.<ref name="anatomy">Dupret, V. (2004). The pleurosaurs: anatomy and phylogeny. ''Revue de Paléobiologie'', '''9''': 61-80.[https://scholar.google.com/scholar?hl=en&q=The+pleurosaurs+%3A+anatomy+and+phylogeny&btnG=&as_sdt=1%2C31&as_sdtp=]</ref>

== History of discovery == ''Pleurosaurus'' was first described from the Solnhofen Limestone by Christian Erich Hermann von Meyer in 1834, based on the species ''Pleurosaurus goldfussi.'' In 1970 fossils were reported from the lithographic limestones in a quarry near the village of Aiguines in the Canjuers plateau, France. In 1974, ''Pleurosaurus ginsburgi'' was described based on MNHN 1983-4-CNJ 67, a mostly complete skeleton found at the Aiguines quarry.<ref name="anatomy" /> ''Pleurosaurus'' is one of two unambiguous members of the family Pleurosauridae, alongside ''Palaeopleurosaurus'' from the Early Jurassic of Germany.<ref name="anatomy" /> In 2012, fragmentary remains likely belonging to ''P. goldfussi'' were reported from central Poland.<ref>{{Cite journal |last1=Kin |first1=Adrian |last2=Gruszczyński |first2=Michał |last3=Martill |first3=David |last4=Marshall |first4=Jim D. |last5=Błażejowski |first5=Błażej |date=January 2013 |title=Palaeoenvironment and taphonomy of a Late Jurassic (Late Tithonian) Lagerstätte from central Poland |url=https://www.idunn.no/doi/10.1111/j.1502-3931.2012.00322.x |journal=Lethaia |language=en |volume=46 |issue=1 |pages=71–81 |doi=10.1111/j.1502-3931.2012.00322.x |bibcode=2013Letha..46...71K |issn=0024-1164|url-access=subscription }}</ref> ''Acrosaurus frischmanni'' has long been considered a junior synonym of ''Pleurosaurus'' due to its very similar anatomy, though analysis suggesting that it is morphologically mature despite being much smaller than adult ''Pleurosaurus'' individuals suggests that it may be valid.<ref name=":0">{{Cite journal |last=Beccari |first=Victor |last2=Jones |first2=Marc E H |last3=Villa |first3=Andrea |last4=Martino |first4=Roberta |last5=Regnault |first5=Sophie |last6=Glaw |first6=Frank |last7=Rauhut |first7=Oliver W M |date=2026-04-01 |title=The axial skeleton of the tuatara (Rhynchocephalia: Sphenodon ): insights on intraspecific variability, ontogeny, sexual dimorphism, and remarks on fossil taxa |url=https://academic.oup.com/zoolinnean/article/doi/10.1093/zoolinnean/zlaf135/8570147 |journal=Zoological Journal of the Linnean Society |language=en |volume=206 |issue=4 |doi=10.1093/zoolinnean/zlaf135 |issn=0024-4082|url-access=subscription }}</ref>

== Description == ''Pleurosaurus'' is one of the few known aquatic sphenodontians. It reached a maximum body length of {{convert|1.5|m|ft}}.<ref>Michael Benton, Vertebrate Paleontology 2009 p. 455 (3rd Edition)</ref> The body and especially the tail were elongated, while the limbs were comparatively short. The elongated triangular skull was highly modified from those present in other rhynchocephalians <ref name=":1">{{Cite journal|last1=Klein|first1=Nicole|last2=Scheyer|first2=Torsten M.|date=February 2017|title=Microanatomy and life history in Palaeopleurosaurus (Rhynchocephalia: Pleurosauridae) from the Early Jurassic of Germany|url=http://link.springer.com/10.1007/s00114-016-1427-3|journal=The Science of Nature|language=en|volume=104|issue=1–2|pages=4|doi=10.1007/s00114-016-1427-3|pmid=28005148|bibcode=2017SciNa.104....4K|s2cid=27133670|issn=0028-1042|url-access=subscription}}</ref> ''Pleurosaurus goldfussi'' and ''Pleurosaurus ginsburgi'' are distinguished by differing skull proportions, different numbers of presacral vertebrae (50 in ''P. goldfussi'' vs 57 in ''P. ginsburgi''), and considerably shorter forelimbs on ''P. ginsburgi.<ref name="anatomy" />'' The neural spines of the vertebrae were relatively square, about as long as tall. The number of tail vertebrae reached 118 in some individuals of ''Pleurosaurus ginsburgi''. Unlike the living tuatara, the scapula and coracoid did not fuse to each other. Also unlike the living tuatara, ''Pleurosaurus'' did not have fracture planes in its tail vertebrae to allow for caudal autotomy.<ref name=":0" /><gallery widths="200" heights="200"> File:Pleurosaurus goldfussi 678e.jpg|''P. goldfussi'' File:Pleurosaurus goldfussi.JPG|''P. goldfussi'' File:Pleurosaurus ginsburgi 6578.jpg|''P. ginsburgi'' </gallery>

== Paleobiology == thumb|left|Restoration of ''Pleurosaurus goldfussi''''Pleurosaurus'' swam via undulating its tail from side to side (anguilliform locomotion), while it probably used its limbs to steer. It lived in shallow marine environments, and was probably piscivorous.<ref name=":1" />

==References== {{Portal|Paleontology}} {{Reflist}}

Category:Jurassic lepidosaurs Category:Rhynchocephalia Category:Solnhofen fauna Category:Prehistoric reptile genera Category:Fossil taxa described in 1831