Project 198: S. J. Nesbitt. 2011. The Early Evolution of Archosaurs: Relationships and the Origin of Major Clades. Bulletin of the American Museum of Natural History. 352:1-292.
Abstract
Archosaurs have a nearly 250 million year record that originated shortly after the Permian-Triassic extinction event and is continued today by two extant clades, the crocodylians and the avians. The two extant lineages exemplify two bauplan extremes among a diverse and complex evolutionary history, but little is known about the common ancestor of these lineages. Renewed interest in early archosaurs has led to nearly a doubling of the known taxa in the last20 years. This study presents a thorough phylogenetic analysis of 80 species-level taxa ranging from the latest Permian to the early part of the Jurassic using a dataset of 412 characters. Each terminal taxon is explicitly described and all specimens used in the analysis are clearly stated.Additionally, each character is discussed in detail and nearly all of the character states are illustrated in either a drawing or highlighted on a specimen photograph. A combination of novel characters and comprehensive character sampling has bridged previously published analyses that focus on particular archosauriform subclades.
A well-resolved, robustly supported consensus tree (MPTs 360) found a monophyletic Archosauria consisting of two major branches, the crocodylian-line and avian-line lineages. The monophyly of clades such as Ornithosuchidae, Phytosauria, Aetosauria, Crocodylomorpha, and Dinosauria is supported in this analysis. However, phytosaurs are recovered as the closest sister taxon to Archosauria, rather than basal crocodylian-line archosaurs, for the first time. Among taxa classically termed as ‘‘rauisuchians,’’ a monophyletic poposauroid clade was found as the sister taxon to a group of paraphyletic ‘‘rauisuchians’’ and monophyletic crocodylomorphs. Hence, crocodylomorphs are well nested within a clade of ‘‘rauisuchians,’’ and are not more closely related to aetosaurs than to taxa such as Postosuchus. Basal crocodylomorphs such as Hesperosuchus and similar forms (‘‘Sphenosuchia’’) were found as a paraphyletic grade leading to the clade Crocodyliformes. Among avian-line archosaurs, Dinosauria is well supported. A monophyletic clade containing Silesaurus and similar forms is well supported as the sister taxon to Dinosauria. Pterosaurs are robustly supported at the base of the avian line.
A time-calibrated phylogeny of Archosauriformes indicates that the origin and initial diversification of Archosauria occurred during the Early Triassic following the Permian-Triassic extinction. Furthermore, all major basal archosaur lineages except Crocodylomorpha were established by the end of the Anisian. Early archosaur evolution is characterized by high rates of homoplasy, long ghost lineages, and high rates of character evolution. These data imply that much of the early history of Archosauria has not been recovered from the fossil record. Not only were archosaurs diverse by the Middle Triassic, but they had nearly a cosmopolitan biogeographic distribution by the end of the Anisian.
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Project DOI: 10.7934/P198, http://dx.doi.org/10.7934/P198
This project contains | Matrices |
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Download Project SDD File | Total scored cells: 29317 Total media associated with cells: 0 Total labels associated with cell media: 0 |
Characters | |
Total characters: 412 Total characters with associated media: 0 Total characters with media with labels: 0 Total character states: 895 Total character states with associated media: 0 Total character states with media with labels:0 Total unordered/ordered characters:412/0 |
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MorphoBank Project 198
MorphoBank Project 198
- Creation Date:
07 March 2008 - Publication Date:
04 May 2011 - Media downloads: 2
- Matrix downloads: 276
This research
supported by
Authors' Institutions
- American Museum of Natural History (AMNH)
Members
member name | taxa | specimens | media | chars | character
| cell scorings (scored, NPA, "-") | cell
| rules | ||||||
Sterling Nesbitt Project Administrator | 151 | 0 | 0 | 412 | 0 | 0 | 29317 (20455, 7745, 1117) | 0 | 0 | 0 | ||||
MorphoBank Curator Full membership | 0 | 1 | 0 | 0 | 0 | 0 | 0 (0, 0, 0) | 0 | 0 | 0 | ||||
Randall Irmis Full membership | 0 | 0 | 0 | 0 | 0 | 0 | 0 (0, 0, 0) | 0 | 0 | 0 | ||||
Mark Norell Full membership | 0 | 0 | 0 | 0 | 0 | 0 | 0 (0, 0, 0) | 0 | 0 | 0 |
Taxonomic Overview for Matrix 'M559' (83 Taxa)
taxon | unscored cells |
scored cells |
no cell support |
NPA cells |
"-" cells | cell images | labels on cell images |
member access |
[1] † Mesosuchus browni Taxon name last Modified on 12/05/13 | 21 | 330 | 330 | 14 | 47 | 0 | 0 | 4 |
[2] † Prolacerta broomi Taxon name last Modified on 12/05/13 | 9 | 358 | 356 | 4 | 41 | 0 | 0 | 4 |
[3] † Archosaurus rossicus Taxon name last Modified on 12/05/13 | 407 | 5 | 5 | 0 | 0 | 0 | 0 | 4 |
[4] † Proterosuchus fergusi Taxon name last Modified on 12/05/13 | 4 | 363 | 360 | 15 | 30 | 0 | 0 | 4 |
[5] † Erythrosuchus africanus Taxon name last Modified on 12/05/13 | 7 | 362 | 362 | 20 | 23 | 0 | 0 | 4 |
[6] † Vancleavea campi Taxon name last Modified on 12/05/13 | 102 | 281 | 281 | 5 | 24 | 0 | 0 | 4 |
[7] † Chanaresuchus bonapartei Taxon name last Modified on 12/05/13 | 15 | 359 | 359 | 26 | 12 | 0 | 0 | 4 |
[8] † Tropidosuchus romeri Taxon name last Modified on 12/05/13 | 35 | 310 | 310 | 53 | 14 | 0 | 0 | 4 |
[9] † Euparkeria capensis Taxon name last Modified on 12/05/13 | 6 | 395 | 394 | 3 | 9 | 0 | 0 | 4 |
[10] † Parasuchus hislopi Taxon name last Modified on 12/05/13 | 53 | 346 | 346 | 1 | 12 | 0 | 0 | 4 |
[11] † Smilosuchus gregorii Taxon name last Modified on 12/05/13 | 32 | 337 | 337 | 29 | 14 | 0 | 0 | 4 |
[12] † Pseudopalatus pristinus Taxon name last Modified on 12/05/13 | 18 | 381 | 381 | 1 | 12 | 0 | 0 | 4 |
[13] † Gracilisuchus stipanicicorum Taxon name last Modified on 12/05/13 | 27 | 302 | 302 | 74 | 9 | 0 | 0 | 4 |
[14] † Turfanosuchus dabanensis Taxon name last Modified on 12/05/13 | 22 | 260 | 258 | 123 | 7 | 0 | 0 | 4 |
[15] † Ornithosuchus longidens Taxon name last Modified on 12/05/13 | 80 | 272 | 272 | 53 | 7 | 0 | 0 | 4 |
[16] † Riojasuchus tenuisceps Taxon name last Modified on 12/05/13 | 27 | 351 | 351 | 25 | 9 | 0 | 0 | 4 |
[17] † Revueltosaurus callenderi Taxon name last Modified on 12/05/13 | 39 | 366 | 366 | 1 | 6 | 0 | 0 | 4 |
[18] † Stagonolepis robertsoni Taxon name last Modified on 12/05/13 | 94 | 312 | 311 | 2 | 4 | 0 | 0 | 4 |
[19] † Aetosaurus ferratus Taxon name last Modified on 12/05/13 | 115 | 265 | 264 | 31 | 2 | 0 | 0 | 4 |
[20] † Longosuchus meadei Taxon name last Modified on 12/05/13 | 56 | 343 | 332 | 6 | 7 | 0 | 0 | 4 |
[21] † Ticinosuchus ferox Taxon name last Modified on 12/05/13 | 196 | 201 | 196 | 11 | 4 | 0 | 0 | 4 |
[22] † Qianosuchus mixtus Taxon name last Modified on 12/05/13 | 99 | 281 | 281 | 29 | 3 | 0 | 0 | 4 |
[23] † Xilousuchus sapingensis Taxon name last Modified on 12/05/13 | 7 | 117 | 116 | 288 | 0 | 0 | 0 | 4 |
[24] † Arizonasaurus babbitti Taxon name last Modified on 12/05/13 | 24 | 252 | 250 | 124 | 12 | 0 | 0 | 4 |
[25] † Poposaurus gracilis holotype Taxon name last Modified on 12/05/13 | 9 | 38 | 37 | 364 | 1 | 0 | 0 | 4 |
[26] † Poposaurus gracilis yale Taxon name last Modified on 12/05/13 | 22 | 213 | 207 | 164 | 14 | 0 | 0 | 4 |
[27] † Lotosaurus adentus Taxon name last Modified on 12/05/13 | 40 | 309 | 309 | 33 | 30 | 0 | 0 | 4 |
[28] † Sillosuchus longicervix Taxon name last Modified on 12/05/13 | 47 | 78 | 78 | 277 | 10 | 0 | 0 | 4 |
[29] † Effigia okeeffeae Taxon name last Modified on 12/05/13 | 43 | 314 | 314 | 26 | 29 | 0 | 0 | 4 |
[30] † Shuvosaurus inexpectatus Taxon name last Modified on 12/05/13 | 44 | 307 | 307 | 32 | 29 | 0 | 0 | 4 |
[31] † Prestosuchus chiniquensis Taxon name last Modified on 12/05/13 | 21 | 169 | 169 | 220 | 2 | 0 | 0 | 4 |
[32] † UFRGS 0156-T Taxon name last Modified on 12/05/13 | 42 | 166 | 166 | 202 | 2 | 0 | 0 | 4 |
[33] † UFRGS 152-T Taxon name last Modified on 12/05/13 | 35 | 264 | 264 | 110 | 3 | 0 | 0 | 4 |
[34] Combined Prestosuchus Taxon name last Modified on 12/05/13 | 54 | 352 | 352 | 2 | 4 | 0 | 0 | 4 |
[35] † Saurosuchus galilei Taxon name last Modified on 12/05/13 | 48 | 308 | 303 | 54 | 2 | 0 | 0 | 4 |
[36] † Batrachotomus kuperferzellensis Taxon name last Modified on 12/05/13 | 7 | 349 | 345 | 55 | 1 | 0 | 0 | 4 |
[37] † Fasolasuchus tenax Taxon name last Modified on 12/05/13 | 4 | 161 | 161 | 245 | 2 | 0 | 0 | 4 |
[38] † Rauisuchus triradentes Taxon name last Modified on 12/05/13 | 17 | 132 | 132 | 263 | 0 | 0 | 0 | 4 |
[39] † Polonosuchus silesiacus Taxon name last Modified on 12/05/13 | 7 | 118 | 118 | 287 | 0 | 0 | 0 | 4 |
[40] † Postosuchus kirkpatricki Taxon name last Modified on 12/05/13 | 37 | 336 | 336 | 35 | 4 | 0 | 0 | 4 |
[41] † Postosuchus alisonae Taxon name last Modified on 12/05/13 | 9 | 168 | 167 | 233 | 2 | 0 | 0 | 4 |
[42] † CM 73372 Taxon name last Modified on 12/05/13 | 53 | 161 | 160 | 194 | 4 | 0 | 0 | 4 |
[43] † Hesperosuchus agilis Taxon name last Modified on 12/05/13 | 10 | 214 | 213 | 185 | 3 | 0 | 0 | 4 |
[44] † Dromicosuchus grallator Taxon name last Modified on 12/05/13 | 72 | 269 | 268 | 67 | 4 | 0 | 0 | 4 |
[45] † Hesperosuchus "agilis" Taxon name last Modified on 12/05/13 | 19 | 288 | 288 | 100 | 5 | 0 | 0 | 4 |
[46] † Dibothrosuchus elaphros Taxon name last Modified on 12/05/13 | 160 | 217 | 217 | 29 | 6 | 0 | 0 | 4 |
[47] † Terrestrisuchus gracilis Taxon name last Modified on 12/05/13 | 63 | 316 | 316 | 25 | 8 | 0 | 0 | 4 |
[48] † Sphenosuchus acutus Taxon name last Modified on 12/05/13 | 13 | 215 | 214 | 179 | 5 | 0 | 0 | 4 |
[49] † Litargosuchus leptorhynchus Taxon name last Modified on 12/05/13 | 12 | 189 | 188 | 208 | 3 | 0 | 0 | 4 |
[50] † Kayentasuchus walkeri Taxon name last Modified on 12/05/13 | 280 | 106 | 106 | 24 | 2 | 0 | 0 | 4 |
[51] † Orthosuchus stormbergi Taxon name last Modified on 12/05/13 | 72 | 320 | 320 | 6 | 14 | 0 | 0 | 4 |
[52] Alligator mississippiensis Taxon name last Modified on 12/05/13 | 4 | 369 | 366 | 0 | 41 | 0 | 0 | 4 |
[53] † Protosuchus haughtoni Taxon name last Modified on 12/05/13 | 8 | 158 | 158 | 241 | 5 | 0 | 0 | 4 |
[54] † Protosuchus richardsoni Taxon name last Modified on 12/05/13 | 32 | 359 | 359 | 9 | 12 | 0 | 0 | 4 |
[55] † Eudimorphodon ranzii Taxon name last Modified on 12/05/13 | 177 | 191 | 191 | 9 | 35 | 0 | 0 | 4 |
[56] † Dimorphodon macronyx Taxon name last Modified on 12/05/13 | 159 | 200 | 200 | 18 | 35 | 0 | 0 | 4 |
[57] † Lagerpeton chanarensis Taxon name last Modified on 12/05/13 | 7 | 133 | 133 | 252 | 20 | 0 | 0 | 4 |
[58] † Dromomeron gregorii Taxon name last Modified on 12/05/13 | 79 | 42 | 42 | 290 | 1 | 0 | 0 | 4 |
[59] † Dromomeron romeri Taxon name last Modified on 12/05/13 | 313 | 61 | 61 | 18 | 20 | 0 | 0 | 4 |
[60] † Marasuchus lilloensis Taxon name last Modified on 12/05/13 | 28 | 203 | 203 | 165 | 16 | 0 | 0 | 4 |
[61] † Asilisaurus kongwe Taxon name last Modified on 12/05/13 | 11 | 174 | 174 | 211 | 16 | 0 | 0 | 4 |
[62] † Eucoelophysis baldwini Taxon name last Modified on 12/05/13 | 117 | 26 | 26 | 269 | 0 | 0 | 0 | 4 |
[63] † Sacisaurus agudoensis Taxon name last Modified on 12/05/13 | 20 | 90 | 90 | 298 | 4 | 0 | 0 | 4 |
[64] † Lewisuchus admixtus Taxon name last Modified on 12/05/13 | 16 | 129 | 129 | 257 | 10 | 0 | 0 | 4 |
[65] † Pseudolagosuchus majori Taxon name last Modified on 12/05/13 | 39 | 95 | 95 | 261 | 17 | 0 | 0 | 4 |
[66] † Lewisuchus/Pseudolagosuchus Taxon name last Modified on 12/05/13 | 181 | 223 | 223 | 6 | 2 | 0 | 0 | 4 |
[67] † Eocursor parvus Taxon name last Modified on 12/05/13 | 14 | 140 | 140 | 245 | 13 | 0 | 0 | 4 |
[68] † Silesaurus opolensis Taxon name last Modified on 12/05/13 | 19 | 333 | 331 | 37 | 24 | 0 | 0 | 4 |
[69] † Pisanosaurus mertii Taxon name last Modified on 12/05/13 | 15 | 88 | 88 | 292 | 17 | 0 | 0 | 4 |
[70] † Heterodontosaurus tucki Taxon name last Modified on 12/05/13 | 44 | 342 | 340 | 0 | 28 | 0 | 0 | 4 |
[71] † Lesothosaurus diagnosticus Taxon name last Modified on 12/05/13 | 58 | 328 | 327 | 1 | 26 | 0 | 0 | 4 |
[72] † Scutellosaurus lawleri Taxon name last Modified on 12/05/13 | 215 | 168 | 165 | 14 | 16 | 0 | 0 | 4 |
[73] † Herrerasaurus ischigualastensis Taxon name last Modified on 12/05/13 | 45 | 343 | 340 | 1 | 23 | 0 | 0 | 4 |
[74] † Staurikosaurus pricei Taxon name last Modified on 12/05/13 | 12 | 115 | 115 | 272 | 13 | 0 | 0 | 4 |
[75] † Eoraptor lunensis Taxon name last Modified on 12/05/13 | 100 | 282 | 275 | 8 | 23 | 0 | 0 | 4 |
[76] † Saturnalia tupiniquim Taxon name last Modified on 12/05/13 | 190 | 192 | 192 | 9 | 21 | 0 | 0 | 4 |
[77] † Plateosaurus engelhardti Taxon name last Modified on 12/05/13 | 6 | 382 | 380 | 0 | 24 | 0 | 0 | 4 |
[78] † Efraasia minor Taxon name last Modified on 12/05/13 | 66 | 318 | 318 | 2 | 26 | 0 | 0 | 4 |
[79] † Tawa hallae Taxon name last Modified on 12/05/13 | 44 | 343 | 343 | 1 | 24 | 0 | 0 | 4 |
[80] † Coelophysis bauri Taxon name last Modified on 12/05/13 | 31 | 360 | 360 | 0 | 21 | 0 | 0 | 4 |
[81] † Dilophosaurus wetherelli Taxon name last Modified on 12/05/13 | 52 | 336 | 334 | 1 | 23 | 0 | 0 | 4 |
[82] † Allosaurus fragilis Taxon name last Modified on 12/05/13 | 11 | 371 | 371 | 0 | 30 | 0 | 0 | 4 |
[83] † Velociraptor mongoliensis Taxon name last Modified on 12/05/13 | 43 | 335 | 334 | 1 | 34 | 0 | 0 | 4 |
Project downloads
type | number of downloads | Individual items downloaded (where applicable) |
Total downloads from project | 809 | |
Matrix downloads | 276 | Basal archosaurs (276 downloads); |
Project downloads | 525 | |
Media downloads | 2 | M86104 (2 downloads); |
Document downloads | 6 | Copyright information for exemplar media (6 downloads); |