The Clarkforkian North American Stage, on the geologic timescale, is the North American faunal stage according to the North American Land Mammal Ages chronology (NALMA), typically set from 56,800,000 to 55,400,000 years BP lasting 1.4 million years.[1]
Considered to be within the Paleocene, more specifically the Late Paleocene, the Clarkforkian shares its upper boundary with the Thanetian.
The Clarkforkian is preceded by the Tiffanian and followed by the Wasatchian NALMA stages.
Substages
editIt is considered to contain the following substages:
- Cf3: (shares the upper boundary) and lower boundary source of the base of Clarkforkian (approximate) and upper boundary source of the base of the Ypresian (approximate).
- Cf2: Is the lower boundary source of the base of the Clarkforkian (approximate)
- Cf1: Upper boundary source of the base of the Ypresian (approximate)
Fauna
editNotable mammals
editMultituberculata - non-therian mammals
- Ectypodus, neoplagiaulacid multituberculate
Metatheria - marsupials
- Peradectes, peradectid marsupial
Carnivora - carnivores, including living carnivorous mammals
- Didymictis, viverravid carnivoran
Condylarthra - archaic ungulates
- Apheliscus, hyopsodontid condylarth
- Ectocion, phenacodontid condylarth
- Phenacodus, phenacodontid condylarth
- Thryptacodon, raccoon-like arctocyonid condylarth
Creodonta - extinct group of carnivorous mammals
Dinocerata - large, tusked herbivores
- Probathyopsis, early North American uintathere
Eulipotyphla - insectivorous mammals
- Plagioctenodon, nyctitheriid insectivore
- Wyonycteris, nyctitheriid insectivore
Mesonychia - carnivorous hoofed mammals
- Dissacus, dog-sized mesonychid
Pantodonta - large herbivorous mammals
- Coryphodon, semi-aquatic, hippo-like pantodont
- Titanoides, large pantodont
Primatomopha - primates and relatives
- Carpolestes, carpolestid plesiadapiform
- Chiromyoides, small plesiadapid
- Phenacolemur, paromomyid plesiadapiform
- Plesiadapis, plesiadapid plesiadapiform
Rodentia - rodents
Tillodontia - medium sized, digging herbivores
- Esthonyx, esthonychid tillodont
References
edit- ^ Paleobiology Database, Clarkforkian
- ^ Rose, Kenneth D. (1981). "The Clarkforkian Land-Mammal Age and Mammalian Faunal Composition Across the Paleocene-Eocene Boundary". Papers on Paleontology. hdl:2027.42/48626.
- ^ Wilf, Peter; Beard, K. Christopher; Davies-Vollum, K. Sian; Norejko, Jay W. (December 1998). "Portrait of a Late Paleocene (Early Clarkforkian) Terrestrial Ecosystem: Big Multi Quarry and Associated Strata, Washakie Basin, Southwestern Wyoming". PALAIOS. 13 (6): 514. Bibcode:1998Palai..13..514W. doi:10.2307/3515344. ISSN 0883-1351. JSTOR 3515344.
 | This geochronology article is a stub. You can help Wikipedia by expanding it. |