Sauria is the clade containing the most recent common ancestor of Archosauria (which includes crocodilians and birds) and Lepidosauria (which includes squamates and the tuatara), and all its descendants.[1] Since most molecular phylogenies recover turtles as more closely related to archosaurs than to lepidosaurs as part of Archelosauria, Sauria can be considered the crown group of diapsids, or reptiles in general.[2] Depending on the systematics, Sauria includes all modern reptiles[3] or most of them (including birds, a type of archosaur) as well as various extinct groups.[4]
Sauria lies within the larger total group Sauropsida, which also contains various stem-reptiles which are more closely related to reptiles than to mammals.[3] Prior to its modern usage, "Sauria" was used as a name for the suborder occupied by lizards, which before 1800 were considered crocodilians.
Recent genomic studies[5][6][7] and comprehensive studies in the fossil record[8] suggest that turtles are closely related to archosaurs, not to the pre-Saurian parareptiles as previously thought. In cladistic analysis of 2018, Pantestudines (turtles and close relatives) were placed within Diapsida but outside of Sauria.[4]
Synapomorphiesedit
The synapomorphies or characters that unite the clade Sauria also help them be distinguished from stem-saurians in Diapsida or stem-reptiles in clade Sauropsida in the following categories based on the following regions of the body.[9][10][11]
Cephalad Region
Dorsal origin of temporal musculature
Loss of caniniform region in maxillary tooth row
External nares close to the midline
Postparietal absent
Squamosal mainly restricted to top of skull
The occipital flange of the squamosal is little exposed on the occiput
Anterior process of squamosal narrow
Quadrate exposed laterally
Unossified dorsal process of stapes
Stapes slender
Trunk Region
Sacral ribs oriented laterally
Ontogenetic fusion of caudal ribs
Trunk ribs mostly single headed
Pectoral Region
Cleithrum absent
Pelvic Region
Modified ilium
Limb Region
Tubular bone lost
Entepicondylar foramen absent
Radius as long as ulna
Small proximal carpals and tarsal
Fifth distal tarsal absent
Short and stout fifth or hooked metatarsal
Perforating foramen of manus lost
However, some of these characters might be lost or modified in several lineages, particularly among birds and turtles; it is best to see these characters as the ancestral features that were present in the ancestral saurian.[9]
Phylogenyedit
The cladogram shown below follows the most likely result found by an analysis of turtle relationships using both fossil and genetic evidence by M.S. Lee, in 2013. This study found Eunotosaurus, usually regarded as a turtle relative, to be only very distantly related to turtles in the clade Parareptilia.[8]
The cladogram below follows the most likely result found by another analysis of turtle relationships, this one using only fossil evidence, published by Rainer Schoch and Hans-Dieter Sues in 2015. This study found Eunotosaurus to be an actual early stem-turtle, though other versions of the analysis found weak support for it as a parareptile.[12]
The cladogram below follows the analysis of Li et al. (2018). It places turtles within Diapsida but outside of Sauria (the Lepidosauromorpha + Archosauromorpha clade).[4]
^Gauthier, J. A., Kluge, A. G., & Rowe, T. (1988). The early evolution of the Amniota. The phylogeny and classification of the tetrapods, 1, 103-155.
^Simões, Tiago R.; Kammerer, Christian F.; Caldwell, Michael W.; Pierce, Stephanie E. (2022-08-19). "Successive climate crises in the deep past drove the early evolution and radiation of reptiles". Science Advances. 8 (33): eabq1898. doi:10.1126/sciadv.abq1898. ISSN 2375-2548. PMC9390993. PMID 35984885.
^ abEzcurra, M. D.; Scheyer, T. M.; Butler, R. J. (2014). "The origin and early evolution of Sauria: reassessing the Permian saurian fossil record and the timing of the crocodile-lizard divergence". PLOS ONE. 9 (2): e89165. doi:10.1371/journal.pone.0089165. PMC3937355. PMID 24586565.
^ abcLi, Chun; Fraser, Nicholas C.; Rieppel, Olivier; Wu, Xiao-Chun (August 2018). "A Triassic stem turtle with an edentulous beak". Nature. 560 (7719): 476–479. doi:10.1038/s41586-018-0419-1. ISSN 0028-0836. PMID 30135526. S2CID 52067286.
^Wang, Zhuo (27 March 2013). "The draft genomes of soft-shell turtle and green sea turtle yield insights into the development and evolution of the turtle-specific body plan". Nature Genetics. 45 (701–706): 701–6. doi:10.1038/ng.2615. PMC4000948. PMID 23624526.
^Crawford, Nicholas G., et al. "More than 1000 ultraconserved elements provide evidence that turtles are the sister group of archosaurs." Biology letters 8.5 (2012): 783-786.
^Jarvis, E.D.; et al. (2014). "Whole-genome analyses resolve early branches in the tree of life of modern birds". Science. 346 (6215): 1320–1331. doi:10.1126/science.1253451. PMC4405904. PMID 25504713.
^ abLee, M. S. Y. (2013). "Turtle origins: Insights from phylogenetic retrofitting and molecular scaffolds". Journal of Evolutionary Biology. 26 (12): 2729–2738. doi:10.1111/jeb.12268. PMID 24256520. S2CID 2106400.
^ abPough, F. H., Janis, C. M., & Heiser, J. B. (2005). Vertebrate life. Pearson/Prentice Hall.
^Schoch, Rainer R.; Sues, Hans-Dieter (24 June 2015). "A Middle Triassic stem-turtle and the evolution of the turtle body plan". Nature. 523 (7562): 584–587. doi:10.1038/nature14472. PMID 26106865. S2CID 205243837.
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February 16, 2024
sauria, redirects, here, video, game, video, game, clade, containing, most, recent, common, ancestor, archosauria, which, includes, crocodilians, birds, lepidosauria, which, includes, squamates, tuatara, descendants, since, most, molecular, phylogenies, recove. Saurian redirects here For the video game see Saurian video game Sauria is the clade containing the most recent common ancestor of Archosauria which includes crocodilians and birds and Lepidosauria which includes squamates and the tuatara and all its descendants 1 Since most molecular phylogenies recover turtles as more closely related to archosaurs than to lepidosaurs as part of Archelosauria Sauria can be considered the crown group of diapsids or reptiles in general 2 Depending on the systematics Sauria includes all modern reptiles 3 or most of them including birds a type of archosaur as well as various extinct groups 4 SauriansTemporal range Capitanian Present 260 0 Ma PreꞒ Ꞓ O S D C P T J K Pg Nclockwise from top left Agkistrodon contortrix the copperhead a snake Dinemellia dinemelli the white faced buffalo weaver a bird various extinct ornithischian dinosaurs Chelonia mydas the green sea turtle Anurognathus an extinct pterosaur and Alligator mississippiensis the american alligator a crocodilian Scientific classificationDomain EukaryotaKingdom AnimaliaPhylum ChordataClass ReptiliaClade NeodiapsidaClade SauriaMacartney 1802GroupsLepidosauromorpha includes the tuatara lizards snakes and various extinct taxa Archelosauria Archosauromorpha includes crocodilians dinosaurs including birds and various extinct taxa Pantestudines includes turtles Kuehneosauridae Choristodera Sauropterygia Ichthyosauromorpha Thalattosauria Sauria lies within the larger total group Sauropsida which also contains various stem reptiles which are more closely related to reptiles than to mammals 3 Prior to its modern usage Sauria was used as a name for the suborder occupied by lizards which before 1800 were considered crocodilians Contents 1 Systematics 1 1 Synapomorphies 1 2 Phylogeny 2 ReferencesSystematics editRecent genomic studies 5 6 7 and comprehensive studies in the fossil record 8 suggest that turtles are closely related to archosaurs not to the pre Saurian parareptiles as previously thought In cladistic analysis of 2018 Pantestudines turtles and close relatives were placed within Diapsida but outside of Sauria 4 Synapomorphies edit The synapomorphies or characters that unite the clade Sauria also help them be distinguished from stem saurians in Diapsida or stem reptiles in clade Sauropsida in the following categories based on the following regions of the body 9 10 11 Cephalad Region Dorsal origin of temporal musculature Loss of caniniform region in maxillary tooth row External nares close to the midline Postparietal absent Squamosal mainly restricted to top of skull The occipital flange of the squamosal is little exposed on the occiput Anterior process of squamosal narrow Quadrate exposed laterally Unossified dorsal process of stapes Stapes slender Trunk Region Sacral ribs oriented laterally Ontogenetic fusion of caudal ribs Trunk ribs mostly single headed Pectoral Region Cleithrum absent Pelvic Region Modified ilium Limb Region Tubular bone lost Entepicondylar foramen absent Radius as long as ulna Small proximal carpals and tarsal Fifth distal tarsal absent Short and stout fifth or hooked metatarsal Perforating foramen of manus lostHowever some of these characters might be lost or modified in several lineages particularly among birds and turtles it is best to see these characters as the ancestral features that were present in the ancestral saurian 9 Phylogeny edit The cladogram shown below follows the most likely result found by an analysis of turtle relationships using both fossil and genetic evidence by M S Lee in 2013 This study found Eunotosaurus usually regarded as a turtle relative to be only very distantly related to turtles in the clade Parareptilia 8 Diapsida Araeoscelidia nbsp Neodiapsida Claudiosaurus nbsp Younginiformes nbsp Sauria Lepidosauromorpha nbsp Archosauromorpha Pantestudines Eosauropterygia nbsp Placodontia nbsp Sinosaurosphargis Odontochelys Testudinata ProganochelysTestudines nbsp Choristodera nbsp Prolacertiformes nbsp Trilophosaurus nbsp Rhynchosauria nbsp Archosauriformes nbsp Archelosauria The cladogram below follows the most likely result found by another analysis of turtle relationships this one using only fossil evidence published by Rainer Schoch and Hans Dieter Sues in 2015 This study found Eunotosaurus to be an actual early stem turtle though other versions of the analysis found weak support for it as a parareptile 12 Sauria Ankylopoda Kuehneosauridae nbsp Lepidosauria Rhynchocephalia nbsp Squamata nbsp Pantestudines Sauropterygia Eosauropterygia nbsp Sinosaurosphargis Placodontia nbsp Eunotosaurus Pappochelys nbsp Odontochelys Testudinata ProganochelysTestudines nbsp Lepidosauromorpha Archosauromorpha nbsp nbsp The cladogram below follows the analysis of Li et al 2018 It places turtles within Diapsida but outside of Sauria the Lepidosauromorpha Archosauromorpha clade 4 Parareptilia nbsp Eureptilia Captorhinidae nbsp Paleothyris nbsp Diapsida Araeoscelidia nbsp Hovasaurus nbsp Younginacrown group Pantestudines Acerosodontosaurus Claudiosaurus Eunotosaurus Pappochelys nbsp Eorhynchochelys nbsp OdontochelysTestudinata nbsp Sauria Lepidosauromorpha Kuehneosauridae nbsp Saurosphargidae Eosauropterygia nbsp Placodus nbsp Lepidosauria Rhynchocephalia nbsp Squamata nbsp Archosauromorpha Trilophosaurus nbsp Rhynchosauria nbsp Prolacerta nbsp Archosauriformes nbsp nbsp References edit Gauthier J A Kluge A G amp Rowe T 1988 The early evolution of the Amniota The phylogeny and classification of the tetrapods 1 103 155 Simoes Tiago R Kammerer Christian F Caldwell Michael W Pierce Stephanie E 2022 08 19 Successive climate crises in the deep past drove the early evolution and radiation of reptiles Science Advances 8 33 eabq1898 doi 10 1126 sciadv abq1898 ISSN 2375 2548 PMC 9390993 PMID 35984885 a b Ezcurra M D Scheyer T M Butler R J 2014 The origin and early evolution of Sauria reassessing the Permian saurian fossil record and the timing of the crocodile lizard divergence PLOS ONE 9 2 e89165 doi 10 1371 journal pone 0089165 PMC 3937355 PMID 24586565 a b c Li Chun Fraser Nicholas C Rieppel Olivier Wu Xiao Chun August 2018 A Triassic stem turtle with an edentulous beak Nature 560 7719 476 479 doi 10 1038 s41586 018 0419 1 ISSN 0028 0836 PMID 30135526 S2CID 52067286 Wang Zhuo 27 March 2013 The draft genomes of soft shell turtle and green sea turtle yield insights into the development and evolution of the turtle specific body plan Nature Genetics 45 701 706 701 6 doi 10 1038 ng 2615 PMC 4000948 PMID 23624526 Crawford Nicholas G et al More than 1000 ultraconserved elements provide evidence that turtles are the sister group of archosaurs Biology letters 8 5 2012 783 786 Jarvis E D et al 2014 Whole genome analyses resolve early branches in the tree of life of modern birds Science 346 6215 1320 1331 doi 10 1126 science 1253451 PMC 4405904 PMID 25504713 a b Lee M S Y 2013 Turtle origins Insights from phylogenetic retrofitting and molecular scaffolds Journal of Evolutionary Biology 26 12 2729 2738 doi 10 1111 jeb 12268 PMID 24256520 S2CID 2106400 a b Pough F H Janis C M amp Heiser J B 2005 Vertebrate life Pearson Prentice Hall Laurin Michel and Jacques A Gauthier 2011 Diapsida Lizards Sphenodon crocodylians birds and their extinct relatives Version 20 April 2011 http tolweb org Diapsida 14866 2011 04 20 in The Tree of Life Web Project http tolweb org Laurin Michel and Jacques A Gauthier 2011 Autapomorphies of Diapsid Clades Version 20 April 2011 http tolweb org accessory Autapomorphies of Diapsid Clades acc id 465 in The Tree of Life Web Project http tolweb org Schoch Rainer R Sues Hans Dieter 24 June 2015 A Middle Triassic stem turtle and the evolution of the turtle body plan Nature 523 7562 584 587 doi 10 1038 nature14472 PMID 26106865 S2CID 205243837 nbsp Wikimedia Commons has media related to Sauria Retrieved from https en wikipedia org w index php title Sauria amp oldid 1200327532, wikipedia, wiki, book, books, library,
