The Early Evolution of Archosaurs: Relationships and the Origin of Major Clades

@inproceedings{Nesbitt2011TheEE,
  title={The Early Evolution of Archosaurs: Relationships and the Origin of Major Clades},
  author={Sterling J. Nesbitt},
  year={2011}
}
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 last 20 years. This study presents… Expand
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A sail-backed suchian from the Heshanggou Formation (Early Triassic: Olenekian) of China
  • S. Nesbitt, J. Liu, Chun Li
  • Geology
  • Earth and Environmental Science Transactions of the Royal Society of Edinburgh
  • 2010
ABSTRACT The two major lineages of extant archosaurs, crocodylians and avians, diverged in the Triassic, but the details and timing of this event are incompletely understood. Fragmentary and… Expand
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The Origin and Early Evolution of Sauria: Reassessing the Permian Saurian Fossil Record and the Timing of the Crocodile-Lizard Divergence
TLDR
A revision suggests a minimum fossil calibration date for the crocodile-lizard split of 254.7 Ma, and early archosauromorph growth strategies appear to be more diverse than previously suggested based on new data on the osteohistology of Aenigmastropheus. Expand
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References

SHOWING 1-10 OF 278 REFERENCES
PROGRESS AND FUTURE DIRECTIONS IN ARCHOSAUR PHYLOGENETICS
TLDR
The basic structure of archosaurian phylogeny is understood to include two primary crown-group lineages—one leading to living crocodiles and including a broad diversity of Triassic animals and another leading to dinosaurs. Expand
The higher-level phylogeny of Archosauria (Tetrapoda: Diapsida)
TLDR
This analysis produces a well-resolved phylogeny, which recovers mostly traditional relationships within Avemetatarsalia, places Phytosauria as a basal crurotarsan clade, finds a close relationship between Aetosaurian and Crocodylomorpha, and recovers a monophyletic Rauisuchia comprised of two major subclades. Expand
Ecologically distinct dinosaurian sister group shows early diversification of Ornithodira
TLDR
The analysis suggests that the dentition and diet of silesaurids, ornithischians and sauropodomorphs evolved independently from a plesiomorphic carnivorous form, and Asilisaurus demonstrates the antiquity of both Ornithodira and the dinosaurian lineage. Expand
Arizonasaurus and its implications for archosaur divergence
  • S. Nesbitt
  • Biology, Medicine
  • Proceedings of the Royal Society of London. Series B: Biological Sciences
  • 2003
TLDR
Characteristics of the skeleton of Arizonasaurus show that it belongs to a poorly known group of Middle Triassic archosaurs called the ctenosauriscids, and that cteno-poposaurs are or are closely related to poposaurs, which suggests that the divergence of birds and crocodiles occurred earlier than previously thought. Expand
Basal Archosaurs: Phylogenetic Relationships and Functional Implications
TLDR
Erect posture has been identified as the key adaptation (possibly associated with locomotor stamina) that resulted in the archosaurian radiation. Expand
Early dinosaurs: A phylogenetic study
TLDR
A new cladistic analysis of the early dinosaur radiation was performed to assess the relationships among the three major clades (Ornithischia, Sauropodomorpha and Theropoda) and to define the phylogenetic position of the basal members of the group. Expand
Sarmatosuchus and the early history of the Archosauria
TLDR
Evidence suggesting that proterosuchids may have existed with erythrosuchids and early crown-group archosaurs in the Middle Triassic requires a revision of the understanding of the earl... Expand
A primitive ornithischian dinosaur from the Late Triassic of South Africa, and the early evolution and diversification of Ornithischia
Although the group played an important role in the evolution of Late Mesozoic terrestrial ecosystems, the early evolutionary history of the ornithischian dinosaurs remains poorly understood. Here, we… Expand
The phylogenetic relationships of early dinosaurs: a comparative report
TLDR
A comparative approach is taken here to show, first, that character choice is a major factor behind differing results; only half of the character data critical for each interpretation is incorporated into the opposing analysis. Expand
A new species of Azendohsaurus (Diapsida: Archosauromorpha) from the Triassic Isalo Group of southwestern Madagascar: cranium and mandible
TLDR
A new species of Azendohsaurus is described from the Middle–Late Triassic of Madagascar, extending the geographical range of a taxon known otherwise only by a single species from Morocco and indicating a complex evolution and distribution of features traditionally thought to be derived within archosaurs. Expand
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