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Archosauria (crocodiles, dinosaurs, birds and their relatives)
Life >
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>
Opisthokonta >
Metazoa
(animals) > Bilateria > Deuterostomia >
Chordata >
Craniata > Vertebrata (vertebrates) > Gnathostomata (jawed vertebrates) >
Teleostomi (teleost fish) > Osteichthyes (bony fish) > Class:
Sarcopterygii (lobe-finned fish) > Stegocephalia (terrestrial vertebrates) >
Tetrapoda
(four-legged vertebrates) > Reptiliomorpha > Amniota >
Reptilia > Romeriida > Diapsida > Archosauromorpha
> Archosauriformes
The oldest archosaur fossils date back to the Early
Triassic (245 million years ago) and show the following skeletal modifications
that distinguish them from their archosauromorph ancestors:
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no pineal foramen (opening) in the roof of the skull;
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no teeth on the palate
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no bony plates (intercentra) between the vertebrae;
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special flexible ankle joint;
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bony armour in the skin covering the body; and
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a third opening in the skull, between the eye socket
and the nasal cavity – the antorbital fenestra.
Classification
Based on Nesbitt (2011). '#' indicates the taxon is known only from fossils,
with no living representatives.
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Pseudosuchia (crocodiles and extinct relatives)
In the phylogeny of Brusatte et al. (2010), the sister group to the
Avemetatarsalia is given as Crurotarsi, not Pseudosuchia. The position of
Crurotarsi is defined on the joint presence of both crocodiles and
phytosaurs and as Nesbitt (2011) places phytosaurs as the sister group to
the archosaurs, Crurotarsi ends up at a higher level than the archosaurs
(see Archosauriformes). |
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# Ornithosuchidae |
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Suchia |
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# basal suchians
Include the following fossil taxa, none of which is known
from fossils collected in southern Africa: Gracilisuchus (from
Argentina), Turfanosuchus (from China), Aetosauria (from Europe and
the USA and including Revueltosaurus, Aetosaurus, Stagonolepis and
Longosuchus) and Ticinosuchus (from Switzerland). |
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Paracrocodylomorpha |
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# Poposauroidea
Includes the following fossil genera, none of which is
known from fossils collected in southern Africa: Qianosuchus (from
China), Arizonasaurus (from USA), Xilousuchus (from China),
Poposaurus (from USA), Lotosaurus (from China), Sillosuchus
(from Argentina), Shuvosaurus (from USA) and Effigia (from
USA). |
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Loricata |
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# basal loricatans
Includes the following fossil groups, none of which is
known from fossils collected in southern Africa: Prestosuchus (from
Brazil), Saurosuchus (from Argentina), Batrachotomus (from
Germany), Fasolasuchus (from Argentina) and the Rauisuchidae (from
Brazil, Poland and the USA and including Rauisuchus, Polonosuchus and
Postasuchus). |
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Crocodylomorpha (crocodiles and extinct relatives)
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Avemetatarsalia (dinosaurs, birds and extinct relatives) |
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# Pterosauromorpha |
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Dinosauromorpha |
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# Lagerpetidae |
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Dinosauriformes |
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# basal Dinosauriformes |
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# Silesauridae |
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Dinosauria (dinosaurs, including birds) |
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Publications
- Nesbitt SJ. 2011. The early evolution of archosaurs:
relationships and the origin of major clades. Bulletin of the
American Museum of Natural History 352: 1-292.
Text by Roger Smith and Hamish Robertson |
