Puercan

{{Short description|North American faunal 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 66,000,000 to 63,800,000 years Before Present, lasting {{Mya|66-63.8|million years}}.<ref name="Barnoskyetal2014">{{cite journal |last1=Barnosky |first1=A. D. |last2=Holmes |first2=M. |last3=Kircholtes |first3=R. |last4=Lindsey |first4=E. |last5=Maguire |first5=K. C. |last6=Poust |first6=A. W. |last7=Stegner |first7=M. A. |last8=Sunseri |first8=J. |last9=Swartz |first9=B. |last10=Swift |first10=J. |last11=Villavicencio |first11=N. A. |date=2014 |title=Prelude to the Anthropocene: Two new North American land mammal ages (NALMAs) |url=https://escholarship.org/uc/item/0hs1w9js |journal=The Anthropocene Review |volume=1 |issue=3 |pages=225–242 |doi=10.1177/2053019614547433 |s2cid=128697655}}</ref>

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.<ref name=":1" />

== Mammal fauna == 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'')<ref name=":0">{{Cite journal |last=Williamson |first=Thomas E. |last2=Brusatte |first2=Stephen L. |last3=Carr |first3=Thomas D. |last4=Weil |first4=Anne |last5=Standhardt |first5=Barbara R. |date=2012-12-01 |title=The phylogeny and evolution of Cretaceous–Palaeogene metatherians: cladistic analysis and description of new early Palaeocene specimens from the Nacimiento Formation, New Mexico |url=https://www.tandfonline.com/doi/full/10.1080/14772019.2011.631592 |journal=Journal of Systematic Palaeontology |language=en |volume=10 |issue=4 |pages=625–651 |doi=10.1080/14772019.2011.631592 |issn=1477-2019|url-access=subscription }}</ref> and cimolestans (such as ''Cimolestes'')''.'' Other groups first appearing in North America during the Puercan include:<ref name=":1">{{Citation |last=Lofgren |first=Donald L. |title=3. Paleocene Biochronology: The Puercan Through Clarkforkian Land Mammal Ages |date=2004 |work=Late Cretaceous and Cenozoic Mammals of North America |pages=43–105 |editor-last=Woodburne |editor-first=Michael O. |url=https://www.degruyter.com/document/doi/10.7312/wood13040-005/html |access-date=2026-04-07 |publisher=Columbia University Press |doi=10.7312/wood13040-005 |isbn=978-0-231-13040-0 |jstor=10.7312/wood13040.9 |last2=Lillegraven |first2=Jason A. |last3=Clemens |first3=William A. |last4=Gingerich |first4=Philip D. |last5=Williamson |first5=Thomas E.|url-access=subscription }}</ref>

* 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 (''Carsioptychus'', ''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

==Substages== The Puercan is considered to contain the following substages:<ref name=":1" />

* '''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.<ref name=":1" /> The earliest ''Peradectes'' fossils are now classified as ''Thylacodon''.<ref name=":0" /> ** 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.<ref name=":1" />

*'''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.<ref name=":1" /> ''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.<ref>{{Cite journal |last=Krause |first=David W. |last2=Weaver |first2=Lucas N. |last3=Chester |first3=Stephen G. B. |last4=Scott |first4=Craig S. |last5=Weissenburger |first5=Ken |last6=Crowell |first6=Jordan W. |last7=Hummel |first7=Rudolph R. |last8=Lyson |first8=Tyler R. |date=2026-05-27 |title=Taeniolabis simmonsae (Multituberculata, Taeniolabididae) from the early Paleocene of the Denver Basin, Colorado: implications for taeniolabidid taxonomy and biochronology of the Puercan North American Land Mammal Age |url=https://doi.org/10.1007/s10914-026-09817-3 |journal=Journal of Mammalian Evolution |language=en |volume=33 |issue=3 |pages=28 |doi=10.1007/s10914-026-09817-3 |issn=1573-7055|url-access=subscription }}</ref>

== Fossil localities == The Puercan is named after the "Puerco marls" or "Puerco Formation", historical terms for the lower part of the Nacimiento Formation in San Juan Basin, New Mexico. Some examples of strata preserving Puercan-age fossils include:<ref name=":1" />

* Alberta: ** Willow Creek Formation (Pu2 Sheep Ahoy! fauna)<ref>{{Cite journal |last=Scott |first=Craig S. |date=2021 |title=First mammal from the Willow Creek Formation: a new early Paleocene ptilodontid (Mammalia, Multituberculata) from near Calgary, Alberta, Canada |url=https://cdnsciencepub.com/doi/abs/10.1139/cjes-2020-0151 |journal=Canadian Journal of Earth Sciences |volume=58 |issue=6 |pages=505–518 |doi=10.1139/cjes-2020-0151 |issn=0008-4077|hdl=1807/105549 |hdl-access=free }}</ref> * Colorado: ** Denver Formation (Pu1 Littleton local fauna, Pu2–Pu3 Corral Bluffs) * North Dakota: ** Ludlow Formation (Pu2–Pu3 Pita Flats) * New Mexico: ** Nacimiento Formation (Pu2–Pu3 Arroyo Chijuillita Member) * Montana: ** Crazy Mountains Basin: Bear Formation (Pu2–Pu3 Simpson Quarry) ** Williston Basin: *** Hell Creek Formation (Pu1 Bug Creek Anthills, Harbicht Hill) *** Fort Union Formation Tullock Member (Pu3 Purgatory Hill, Garbani Channel) *** Fort Union Formation Ludlow Member (Pu2 Hiatt local fauna) * Saskatchewan: ** Ravenscrag Formation (Pu1 Frenchman, Long Fall, Pu3 Croc Pot) * Texas: ** Black Peaks Formation (Pu3?) * Utah: ** North Horn Formation (Pu2 Gas Tank Hill local fauna, Pu3 Wagonroad) * Wyoming: ** Bighorn Basin: Fort Union Formation (Pu1 Mantua Lentil local fauna, Pu1 Leidy Quarry) ** Great Divide Basin: Fort Union Formation (Pu1 China Butte Member)<ref>{{Cite journal |last=Atteberry |first=Madelaine R. |last2=Eberle |first2=Jaelyn J. |date=2021-04-18 |title=New earliest Paleocene (Puercan) periptychid ‘condylarths’ from the Great Divide Basin, Wyoming, USA |url=https://www.tandfonline.com/doi/full/10.1080/14772019.2021.1924301 |journal=Journal of Systematic Palaeontology |language=en |volume=19 |issue=8 |pages=565–593 |doi=10.1080/14772019.2021.1924301 |issn=1477-2019|url-access=subscription }}</ref> ** Hanna Basin: Ferris Formation (Pu1–Pu3)

==References== {{reflist}}

Category:Puercan Category:Paleocene life