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Sauria

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Sauria is the clade containing the most recent common ancestor of archosaurs (such as crocodilians, dinosaurs, etc.) and lepidosaurs (lizards and kin), 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.

Systematics

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]

Synapomorphies

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]

Phylogeny

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 Spinoaequalis schultzei reconstruction flipped.jpg

Neodiapsida

Claudiosaurus Claudiosaurus white background.jpg

Younginiformes Hovasaurus BW flipped.jpg

Sauria

LepidosauromorphaBritish reptiles, amphibians, and fresh-water fishes (1920) (Lacerta agilis).jpg

Archosauromorpha

ChoristoderaHyphalosaurus mmartyniuk wiki flipped.png

Prolacertiformes Prolacerta broomi.jpg

TrilophosaurusTrilophosaurus buettneri (flipped).jpg

RhynchosauriaHyperodapedon BW2 white background.jpg

ArchosauriformesDeinosuchus riograndensis.png

Pantestudines

EosauropterygiaDolichorhynchops BW flipped.jpg

PlacodontiaPsephoderma BW flipped.jpg

Sinosaurosphargis

Odontochelys

Testudinata

Proganochelys

TestudinesErpétologie générale, ou, Histoire naturelle complète des reptiles (Centrochelys sulcata).jpg

(=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

ArchosauromorphaDeinosuchus riograndensis.pngMeyers grosses Konversations-Lexikon - ein Nachschlagewerk des allgemeinen Wissens (1908) (Antwerpener Breiftaube).jpg

Ankylopoda

KuehneosauridaeIcarosaurus white background.jpg

Lepidosauria

SquamataBritish reptiles, amphibians, and fresh-water fishes (1920) (Lacerta agilis).jpg

RhynchocephaliaHatteria white background.jpg

Pantestudines

EosauropterygiaDolichorhynchops BW flipped.jpg

Sinosaurosphargis

PlacodontiaPsephoderma BW flipped.jpg

Eunotosaurus

PappochelysBild2 Ur-Schildkröte Zeichnung.jpg

Odontochelys

Testudinata

Proganochelys

TestudinesErpétologie générale, ou, Histoire naturelle complète des reptiles (Centrochelys sulcata).jpg

(=Lepidosauromorpha) (=Archelosauria)

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]

ParareptiliaScutosaurus BW flipped.jpg

Eureptilia

CaptorhinidaeLabidosaurus.jpg

PaleothyrisPaleothyris 02.png

Diapsida

AraeoscelidiaPetrolacosaurus BW.jpg

HovasaurusHovasaurus BW.jpg

Youngina

crown‑group Pantestudines

Acerosodontosaurus

Claudiosaurus

Eunotosaurus

PappochelysBild2 Ur-Schildkröte Zeichnung.jpg

EorhynchochelysEorhynchochelys NT.png

Odontochelys

TestudinataErpétologie générale, ou, Histoire naturelle complète des reptiles (Centrochelys sulcata).jpg

Sauria Archosauromorpha

ArchosauriformesDeinosuchus riograndensis.pngMeyers grosses Konversations-Lexikon - ein Nachschlagewerk des allgemeinen Wissens (1908) (Antwerpener Breiftaube).jpg

ProlacertaProlacerta broomi.jpg

TrilophosaurusTrilophosaurus buettneri (flipped).jpg

RhynchosauriaHyperodapedon BW2 white background.jpg

Lepidosauromorpha Lepidosauria

RhynchocephaliaHatteria white background.jpg

SquamataBritish reptiles, amphibians, and fresh-water fishes (1920) (Lacerta agilis).jpg

KuehneosauridaeIcarosaurus white background.jpg

EosauropterygiaDolichorhynchops BW flipped.jpg

PlacodusPlacodus BW.jpg

Saurosphargidae

References

  1. ^ 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.
  2. ^ 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. PMC 9390993. PMID 35984885.
  3. ^ 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.
  4. ^ 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.
  5. ^ 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.
  6. ^ 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.
  7. ^ 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.
  8. ^ 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.
  9. ^ a b Pough, F. H., Janis, C. M., & Heiser, J. B. (2005). Vertebrate life. Pearson/Prentice Hall.
  10. ^ 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/
  11. ^ 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/
  12. ^ 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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Sauria: Brief Summary

provided by wikipedia EN

Sauria is the clade containing the most recent common ancestor of archosaurs (such as crocodilians, dinosaurs, etc.) and lepidosaurs (lizards and kin), and all its descendants. 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. Depending on the systematics, Sauria includes all modern reptiles or most of them (including birds, a type of archosaur) as well as various extinct groups.

Sauria lies within the larger total group Sauropsida, which also contains various stem-reptiles which are more closely related to reptiles than to mammals. Prior to its modern usage, "Sauria" was used as a name for the suborder occupied by lizards, which before 1800 were considered crocodilians.

license
cc-by-sa-3.0
copyright
Wikipedia authors and editors
original
visit source
partner site
wikipedia EN