Archosauria
Archosauria or archosaurs is a clade of diapsid sauropsid tetrapods, with birds and crocodilians being the only known extant representatives. Although broadly classified as reptiles, which traditionally exclude birds, the cladistic sense of the term includes all living and extinct relatives of birds and crocodilians such as non-avian dinosaurs, pterosaurs, phytosaurs, aetosaurs and rauisuchians as well as many Mesozoic marine reptiles. Modern paleontologists define Archosauria as a crown group that includes the most recent common ancestor of living birds and crocodilians, and all of its descendants.

This Photo was taken by Timothy A. Gonsalves . Feel free to use my photos, but please mention me as the author. I wou… · CC BY-SA 4.0 · via Wikipedia/Commons. May be a photograph of a specimen, or an artist’s reconstruction — an interpretation of a skeleton, since colour and soft tissue are almost never preserved.
On record
Recorded, not inferred- Also called
- archosaurPBDB
- Sits inside
- EucrocopodaPBDB
- Motility
- actively mobilePBDB, for Osteichthyes
- Environment
- terrestrialPBDB, for Diapsida
Time the record covers
At least 250 million years on record.
The record covers at least 250.8 Mya to 11.7 ka. No occurrence read is dated outside 259.857 Mya to 0 Mya.
12,000+ occurrences of Archosauria on record. The Paleobiology Database records this as a living group. Bar height is expected occurrences, not a count: each fossil is spread across the span it is dated to, so a tall narrow bar means tight dating and a low wide one means loose.
When
12,000 occurrences read- Permianunder 1%
- Early Triassicunder 1%
- Middle Triassicunder 1%
- Late Triassic5%
- Early Jurassic5%
- Middle Jurassic3%
- Late Jurassic10%
- Early Cretaceous16%
- Late Cretaceous44%
- Paleoceneunder 1%
- Eocene4%
- Oligoceneunder 1%
- Miocene4%
- Pliocene3%
- Pleistocene6%
- Holoceneunder 1%
These are dates about fossils, not the animal: the record can only begin after it arose and end before it died out, so either end may reach further. Shares are expected occurrences: a fossil dated to a span is counted partly in each period it straddles. The read hit its cap, so every figure above is a floor and the shares are of the occurrences read. More on what this infers.
Found in
at least 1053 formations
- Morrison Formation671
- Hell Creek Formation · Montana Group628
- Dinosaur Park Formation · Belly River Group568
- Oldman Formation · Belly River Group284
- Fruitland/Kirtland Formation271
- Lance Formation · Montana Group251
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The named rock units Archosauria has been recovered from, largest first. Drawn where the rock is now, not where it formed. The read hit its cap, so each count is a floor. 1,029 further formations hold fewer occurrences each and are not listed. 1,512 occurrences have no formation on record, which is common for older literature.
Found in the same rock
2,375 taxa- Crocodylus33 sites
- Bovidae31 sites
- Clarias29 sites
- Osteichthyes26 sites
- Hipparion25 sites
- Reptilia25 sites
- Aves24 sites
- Tragelaphus24 sites
- Trionychidae24 sites
- Alcelaphini22 sites
- Equus20 sites
- Gazella20 sites
- Ceratotherium19 sites
- Mammalia19 sites
- Trionyx19 sites
- Geochelone18 sites
- Hystrix17 sites
- Kobus17 sites
- Cercopithecidae16 sites
- Hippopotamus amphibius15 sites
- Reduncini15 sites
- Crocodylus niloticus14 sites
- Hippopotamus14 sites
- Palaeoloxodon recki14 sites
The Paleobiology Database records at least 931 sites for Archosauria, and this reads 240 of them. The number is how many of those sites it was catalogued from too. The 24 sharing the most are listed.
This is not a list of everything alive at the time. It is only what has come out of the same ground as this animal and been written down.
Entered from
at least 3,334 references- Dinozavri severnoi Yevrazii: Novye dannye o sostave kompleksov, ekologii i paleobiogeografii [Dinosaurs of northern Eurasia: new data about assemblages, ecology, and paleobiogeography]357
- Paleontological survey, resource assessment, and mitigation plan for the Bisti-Star Lake Area, northwestern New Mexico316
- Fossil Vertebrate Collections279
- Vertebrate biostratigraphy of the Hell Creek Formation in southwestern North Dakota and northwestern South Dakota254
- The paleogeographic and stratigraphic distribution of ceratopsids (Ornithischia) in the Upper Judith River Group of western Canada188
- Vertebrate microsite assemblages (exclusive of mammals) from the Foremost and Oldman Formations of the Judith River Group (Campanian) of southeastern Alberta: an illustrated guide172
- Stratigraphy and mammalian paleontology of the McCullough Peaks, northern Bighorn Basin, Wyoming: Implications for biochronology, basin development, and community reorganization across the Paleocene-Eocene boundary169
- Paleontology of the Judith River Formation (Campanian) of Dinosaur National Park, Alberta, Canada: evidence from vertebrate microfossil locality136
- Stratigraphy and paleontology of the Cloverly Formation (Lower Cretaceous) of the Bighorn Basin area, Wyoming and Montana132
- Miocene and Pliocene birds from the Lee Creek Mine, North Carolina105
- Paleoecological analysis of the vertebrate fauna of the Morrison Formation (Upper Jurassic), Rocky Mountain region, U.S.A.90
- Fossil vertebrates from the Late Cretaceous Lance Formation, eastern Wyoming72
Each of the 12,000 occurrences read was entered from one of these publications, ordered by how many each accounts for. This is not a search for papers mentioning the name. That read hit its cap, so each count is a floor. 3,322 further references are not listed. Entries link to doi.org where the Paleobiology Database holds an identifier, and to its own record where it does not. Relayed as the Paleobiology Database holds them, not checked against what they resolve to.
Media and terms
Media content3
Picture of Archosauria
- Source
- Wikipedia/Commons
- Credit
- This Photo was taken by Timothy A. Gonsalves . Feel free to use my photos, but please mention me as the author. I wou…
- Licence
- CC BY-SA 4.0
- Commercial use
- the licence allows it
Photogrammetry
- Source
- MorphoSource
- Credit
- Zion National Park
- Licence
- not stated by the source
- Commercial use
- cannot be read from the licence given — check the record
- Specimen
- Archosauria indet. · ZION
3D model
- Source
- Sketchfab
- Licence
- CC Attribution-NonCommercial-ShareAlike
- Commercial use
- the licence does not allow it
Smithsonian Open Access was not reached for this taxon, so this list is what the others held rather than everything there is.
The description on this site
- Source
- Wikipedia, “Archosaur”
- Licence
- CC BY-SA 4.0
This is what the site found, which is not the same as what exists.
Keep going
What may have been alongside itEucrocopoda through timeThe world it lived on
Occurrence data from the Paleobiology Database, CC BY 4.0. (Cope 1869)