Puercan
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The Puercan North American Stage on the geologic timescale is the first North American faunal stage of the Paleocene epoch, according to the North American Land Mammal Ages (NALMA) chronology. It spans an interval from around 66,000,000 to 63,800,000 years Before Present, lasting 2.2 million years.[1]
The Puercan is the first of four NALMAs corresponding to the Paleocene, followed by the Torrejonian, Tiffanian, and Clarkforkian. The Puercan directly follows the Lancian NALMA, which corresponds to the Maastrichtian age of the Late Cretaceous. The K-Pg boundary and K-Pg mass extinction at 66 million years ago approximates the boundary between the Lancian and Puercan. The Puercan is followed by the Torrejonian NALMA stage.[2]
Few Puercan mammals are closely related to modern North American mammals, most belong to an early adaptive radiation in the aftermath of the K-Pg mass extinction. Some are holdovers from the Cretaceous, such as a diverse array of rodent-like multituberculates alongside marsupial-like mammals (such as Peradectes and Thylacodon)[3] and cimolestans (such as Cimolestes). Other groups first appearing in North America during the Puercan include:[2]
- Leptictidae (Prodiacodon, etc.), hopping insectivores
- Taeniodonta (Onychodectes, Wortmania, etc.), large stocky herbivores
- Purgatorius and Pandemonium, potential early relative of primates
- Viverravidae (Ictidopappus, etc.), small early relatives of carnivoran mammals
- Ravenictis, a tiny early relative of carnivoran mammals
- "Condylarths", a broad category of omnivorous or herbivorous mammals potentially ancestral to later groups such as hoofed mammals and carnivorans.
- "Arctocyonids" (Oxyclaenus, Chriacus, etc.), medium-sized omnivores
- Periptychidae (Periptychus, Ectoconus, Oxyacodon, etc.), stocky terrestrial omnivores
- Hyopsodontidae (Litomylus, etc.), small omnivores potentially related to perissodactyls (odd-toed ungulates)
- Mioclaenidae (Promioclaenus, Bubogonia, etc.), small herbivores potentially related to South American native ungulates
- Triisodontidae (Eoconodon, etc.), stocky terrestrial carnivores
