San Angelo Formation
The San Angelo Formation is a geologic formation in Texas. It preserves fossils dating back to the Permian period. It is one of the geologically youngest formations to preserve fossils of pelycosaurs.
| San Angelo Formation | |
|---|---|
| Stratigraphic range: | |
| Type | Formation |
| Unit of | Pease River Group |
| Underlies | Blaine Formation |
| Overlies | Clear Fork Group |
| Location | |
| Region | Texas |
| Country | United States |
Stratigraphy and age
The San Angelo Formation belongs to the Kungurian stage of the Cisuralian series. It underlies the Blaine Formation, which is either upper Kungurian or lower Guadalupian.[1][2]
Fossil content
Everett C. Olson regarded the San Angelo Formation as preserving some of the oldest known therapsids, several of which he classified in a taxon he called Eotheriodonta.[3] These taxa are now interpreted as caseids and sphenacodontids, not therapsids.[4]
Color key
|
Notes Uncertain or tentative taxa are in small text; |
Synapsids
| Genus | Species | Location | Material | Notes | Images |
|---|---|---|---|---|---|
| Angelosaurus | A. dolani | A caseid | |||
| Caseoides | C. sanangeloensis | A caseid | |||
| Caseopsis | C. agilis | A caseid | |||
| Cotylorhynchus | C. hancocki | A caseid | |||
| Dimacrodon | D. hottoni | ||||
| Dimetrodon | D. angelensis | A sphenacodontid | |||
| Driveria | D. ponderosa | ||||
| Eosyodon | E. hudsoni | A dubious sphenacodontid[5] | |||
| Gorgodon | G. minutus | ||||
| Knoxosaurus | K. niteckii | ||||
| Mastersonia | M. driverensis | ||||
| Steppesaurus | S. gurleyi | ||||
| Tappenosaurus | T. magnus | ||||
References
Bibliography
- DiMichele, William A.; Mamay, Sergius H.; Chaney, Dan S.; Hook, Robert W.; Nelson, W. John (2001). "An Early Permian flora with Late Permian and Mesozoic affinities from North-Central Texas". Journal of Paleontology. 75 (2): 12.
- Kammerer, Christian F. (2011). "Systematics of the Anteosauria (Therapsida: Dinocephalia)". Journal of Systematic Palaeontology. 9 (2): 261–304. doi:10.1080/14772019.2010.492645. ISSN 1477-2019.
- Lucas, Spencer G; Golubev, Valeriy K (2019). "Age and duration of Olson's Gap, a global hiatus in the Permian tetrapod fossil record". Permophiles: 5.
- Olson, Everett C. (1962). "Late Permian Terrestrial Vertebrates, U. S. A. and U. S. S. R." Transactions of the American Philosophical Society. 52 (2): 1–224. doi:10.2307/1005904. ISSN 0065-9746. JSTOR 1005904.
- Olson, Everett C.; Beerbower, James R. (1953). "The San Angelo Formation, Permian of Texas, and Its Vertebrates". The Journal of Geology. 61 (5): 389–423. doi:10.1086/626109. ISSN 0022-1376. JSTOR 30079693.
- Sidor, C. A.; Hopson, J. A. (1995). "The taxonomic status of the Upper Permian eotheriodont therapsids of the San Angelo Formation (Guadalupian), Texas". Journal of Vertebrate Paleontology. 15 (3A): 53A.
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