Puercan

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 to 65.1 million years ago. 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.

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 to 65.1 million years ago. 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.

Substages

The Puercan is considered to contain the following substages: Puercan 1 (Pu1): The oldest substage, starting at the first appearance of the "condylarth" Protungulatum donnae and ending at the first appearance of the periptychid Ectoconus. The marsupial-like mammal Peradectes was sometimes used to characterize the start of Puercan 1, in cases where Protungulatum was regarded as a Cretaceous mammal. The earliest Peradectes fossils are now classified as Thylacodon. Some authors have proposed alternate names for the lowermost part of the Puercan, which may show a transition from Cretaceous to Paleocene faunas: "Mantuan" (named after Mantua Lentil site of Wyoming), "Bugcreekian" (named after the Bug Creek area of Montana), or "Puercan 0". None of these names found widespread adoption. Puercan 2 (Pu2): The second substage, starting at the first appearance of Ectoconus and ending at the first appearance of the multituberculate Taeniolabis taoensis. Puercan 3 (Pu3): The youngest substage, starting at the first appearance of Taeniolabis taoensis and ending at the first appearance of the periptychid Periptychus carinidens, which marks the start of the succeeding Torrejonian NALMA. Kimbetopsalis simmonsae, a multituberculate from Pu2 layers in Colorado, may actually be a species of Taeniolabis, which would extend the range of Taeniolabis down to Pu2.

References

Text derived from https://en.wikipedia.org/w/index.php?oldid=1376926026 under CC BY-SA 4.0; modifications have been made.