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Sphenosuchia

From Wikipedia, the free encyclopedia

Suborder of reptiles

Sphenosuchia Temporal range:Late Triassic -Late Jurassic,228–152 Ma PreꞒ Ꞓ O S D C P T J K Pg N

Life restoration ofHesperosuchus agilis
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Clade:	Archosauria
Clade:	Pseudosuchia
Clade:	Crocodylomorpha
Informal group:	†Sphenosuchia von Huene, 1942
Genera
See below
Synonyms
PedeticosauriaWalker, 1968

Sphenosuchia is asuborder ofbasal crocodylomorphs that first appeared in theTriassic and occurred into theMiddle Jurassic. Most were small, gracile animals with an erect limb posture. They are now thought to be ancestral tocrocodyliforms, a group which includes all livingcrocodilians.

Stratigraphic range

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The earliest known members of the group (i.e.Hesperosuchus) are earlyNorian in age, found in the Blue Mesa Member of theChinle Formation. Only one sphenosuchian is currently known from the Middle Jurassic,Junggarsuchus, from theJunggar Basin (Shishugou Formation) of China during either theBathonian or theCallovian (~165 Ma) age,^[1] and theHallopodidae are known from the Late Jurassic of North America.^[2]

Phylogeny

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Themonophyly of the group is debated, although severalsynapomorphies characterize the clade, including extremely slender limbs, a compactcarpus and an elongatecoracoid process.

In 2002, Clark and Sues found a possible sphenosuchian clade ofDibothrosuchus,Sphenosuchus, and possiblyHesperosuchus andSaltoposuchus, with several other genera in unresolved positions (Kayentasuchus,Litargosuchus,Pseudhesperosuchus, andTerrestrisuchus).^[3] More recently, however, Clarket al. (2004) argued for the paraphyly of the group, contending that morphological characters were secondarily lost in more highly derived crocodylomorphs.^[1] Further analysis and study is required before the group's monophyly is resolved with certainty — a perfect phylogenetic analysis is, at present, impossible due to a paucity of fossil remains demonstrating phylogenetically informative characters.

Below is acladogram modified from Nesbitt (2011).^[4] Sphenosuchians are marked by the green bracket.

CM 73372

	Orthosuchus

	Protosuchus

	Alligator

Sphenosuchians

Genera

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Genus	Status	Age	Location	Unit	Notes
Dibothrosuchus	Valid	Early Jurassic	China	Lower Lufeng Series
Dromicosuchus	Valid	Late Triassic	USA	Newark Supergroup
Dyoplax^[5]	Valid	Late Triassic (Carnian)	Germany	Schilfsandstein Formation	A possible sphenosuchian;^[5] alternatively, it could be anerpetosuchid.^[6]
Hesperosuchus	Valid	Late Triassic (Carnian)	USA	Chinle Formation
Junggarsuchus	Valid	Middle Jurassic	China	Shishugou Formation
Kayentasuchus	Valid	Early Jurassic (Sinemurian -Pliensbachian)	USA	Kayenta Formation
Litargosuchus	Valid	Early Jurassic	South Africa	Elliot Formation
Parrishia	Nomen dubium	Late Triassic	USA	Dockum Group	An indeterminate sphenosuchian known only from undiagnostic vertebrae^[7]
Phyllodontosuchus^[8]	Valid	Early Jurassic	China	Lower Lufeng Series
Pseudhesperosuchus	Valid	Late Triassic (Norian)	Argentina	Los Colorados Formation
Redondavenator	Valid	Late Triassic	USA	Redonda Formation
Saltoposuchus	Valid	Late Triassic (Norian)	Germany Switzerland UK	Löwenstein Formation Trossingen Formation Lossiemouth Sandstone
Sphenosuchus	Valid	Early Jurassic	South Africa	Elliot Formation
Terrestrisuchus	Valid.	Late Triassic	UK
Trialestes	Valid	Late Triassic	Argentina	Ischigualasto Formation

References

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^^a ^bClark, J.M.,et al. (2004).A Middle Jurassic 'sphenosuchian' from China and the origin of the crocodylian skullNature430:1021-1024.
^Leardi, Juan Martin; Pol, Diego; Clark, James Matthew (2017-01-19)."Detailed anatomy of the braincase of Macelognathus vagans Marsh, 1884 (Archosauria, Crocodylomorpha) using high resolution tomography and new insights on basal crocodylomorph phylogeny".PeerJ.5: e2801.doi:10.7717/peerj.2801.ISSN 2167-8359.PMC 5251941.PMID 28133565.
^Clark, James M.; Sues, Hans-Dieter (2002)."Two new basal crocodylomorph archosaurs from the Lower Jurassic and the monophyly of the Sphenosuchia".Zoological Journal of the Linnean Society.136:77–95.doi:10.1046/j.1096-3642.2002.00026.x.
^Nesbitt, S.J. (2011)."The early evolution of archosaurs: relationships and the origin of major clades".Bulletin of the American Museum of Natural History.352:1–292.doi:10.1206/352.1.hdl:2246/6112.S2CID 83493714.
^^a ^bLucas, S. G.; Wild, R.; Hunt, A. P. (1998). "Dyoplax O. Fraas, a Triassic sphenosuchian from Germany".Stuttgarter Beiträge zur Naturkunde, B.263:1–13.
^Michael W. Maisch; Andreas T. Matzke; Thomas Rathgeber (2013). "Re-evaluation of the enigmatic archosaurDyoplax arenaceus O. Fraas, 1867 from the Schilfsandstein (Stuttgart Formation, lower Carnian, Upper Triassic) of Stuttgart, Germany".Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen.267 (3):353–362.doi:10.1127/0077-7749/2013/0317.
^Clark, J. M.; Sues, H.-D.; Berman, D. S. (2001). "A new specimen ofHesperosuchus agilis from the Upper Triassic of New Mexico and the interrelationships of basal crocodylomorph archosaurs".Journal of Vertebrate Paleontology.20 (4):683–704.doi:10.1671/0272-4634(2000)020[0683:ANSOHA]2.0.CO;2.S2CID 7455338.
^Harris, Jerald D.; Lucas, Spencer G.; Estep, J. W.; Jianjun Li (2000). "A new and unusual sphenosuchian (Archosauria: Crocodylomorpha) from the Lower Jurassic Lufeng Formation, People's Republic of China".Neues Jahrbuch für Geologie und Paläontologie, Abhandlungen.215 (1):47–68.doi:10.1127/njgpa/215/2000/47.

Pseudosuchia

Kingdom:Animalia
Phylum:Chordata
Class:Sauropsida
Clade:Archosauria

Sauropsida

- seeSauropsida

Archosauromorpha

seeArchosauromorpha
Pseudosuchia	see below↓

Pseudosuchia

†Dasygnathoides †Nundasuchus †Phytosauria?
†Ornithosuchidae	Aenigmaspina? Dynamosuchus Ornithosuchus Riojasuchus Venaticosuchus

Suchia

†Erpetosuchidae

†Aetosauriformes

Acaenasuchus Euscolosuchus Revueltosaurus
Aetosauria	seeAetosauria

†Gracilisuchidae

Paracrocodylomorpha

- see below↓

Paracrocodylomorpha

†Mambawakale

†Poposauroidea

Benggwigwishingasuchus Lotosaurus Schultzsuchus? Qianosuchus
Ctenosauriscidae	Arizonasaurus Bromsgroveia Bystrowisuchus Ctenosauriscus Hypselorhachis Tsylmosuchus? Xilousuchus
Poposauridae	Dolichobrachium Poposaurus
Shuvosauridae	Effigia Shuvosaurus Sillosuchus

Loricata

†Apatosuchus †Arganasuchus †Batrachotomus †Dagasuchus †Decuriasuchus †Etjosuchus †Fasolasuchus †Heptasuchus †Heteropelta? †Incertovenator? †Luperosuchus †Mandasuchus? †Prestosuchus †Procerosuchus †Saurosuchus †Stagonosuchus †Youngosuchus
†Rauisuchidae	Arganasuchus? Energosuchus? Jushatyria? Polonosuchus Postosuchus Procerosuchus? Rauisuchus Scolotosuchus Scythosuchus? Teratosaurus Tikisuchus? Vivaron Vjushkovisaurus? Vytshegdosuchus?
Crocodylomorpha	see below↓

Crocodylomorpha

†Carnufex †Dibothrosuchus †Dromicosuchus †Hesperosuchus †Heteropelta? †Junggarsuchus †Kayentasuchus †Parrishia †Pattisaura †Phyllodontosuchus †Pseudhesperosuchus †Redondavenator †Sphenosuchus †Syntomiprosopus? †Trialestes
†Saltoposuchidae	Litargosuchus Saltoposuchus Terrestrisuchus
†Hallopodidae	Almadasuchus Hallopus Macelognathus
†Thalattosuchia	seeThalattosuchia

Crocodyliformes

†Entradasuchus †Eopneumatosuchus †Kemkemia †Microchampsa †Platyognathus †Stegomosuchus †Tagarosuchus
†Protosuchidae	Coloradisuchus Dianosuchus Edentosuchus Erythrochampsa Hemiprotosuchus Hoplosuchus Orthosuchus? Pedeticosaurus? Protosuchus
†Notochampsidae	Notochampsa Orthosuchus?
†Gobiosuchidae	Cassissuchus Gobiosuchus Lisboasaurus? Zaraasuchus