The Irvingtonian North American Land Mammal Age on the

geologic timescale The geologic time scale, or geological time scale, (GTS) is a representation of time based on the rock record of Earth. It is a system of chronological dating that uses chronostratigraphy (the process of relating strata to time) and geochronol ...

is the North American

faunal stage In chronostratigraphy, a stage is a succession of rock strata laid down in a single age on the geologic timescale, which usually represents millions of years of deposition. A given stage of rock and the corresponding age of time will by convent ...

according to the

North American Land Mammal Ages The North American land mammal ages (NALMA) establishes a geologic timescale for North American fauna beginning during the Late Cretaceous and continuing through to the present. These periods are referred to as ages or intervals (or stages when ref ...

chronology (NALMA), spanning from 1.9 million – 250,000 years BP.The _Blancan, Irvingtonian and Rancholabrean Mammal Ages
by Christopher J. Bell and Ernest L. Lundelius Jr., Anthony D. Barnosky, Russell W. Graham, Everett H. Lindsay, Dennis R. Ruez Jr., Holmes A. Semken Jr., S. David Webb, and Richard J. Zakrzewski. January 2004 in the book: Late Cretaceous and Cenozoic Mammals of North America: Biostratigraphy and Geochronology. Chapter: 7. Publisher: Columbia University Press; Editors: Michael O. Woodburne. pp274-276 Named after an assemblage of fossils from the Irvington District of

Fremont, California Fremont is a city in Alameda County, California, United States. Located in the East Bay region of the San Francisco Bay Area, Bay Area, Fremont has a population of 230,504 as of 2020, making it the fourth List of cities and towns in the San Fra ...

, (1951) Late Cenozoic vertebrates of the San Francisco Bay region, ''University of California Publications, Bulletin of the Department of Geological Sciences'' 28:215-314 the Irvingtonian is usually considered to overlap the

Lower Pleistocene The Early Pleistocene is an unofficial sub-epoch in the international geologic timescale in chronostratigraphy, being the earliest division of the Pleistocene Epoch within the ongoing Quaternary Period. It is currently estimated to span the time ...

and

Middle Pleistocene The Chibanian, widely known by its previous designation of Middle Pleistocene, is an age in the international geologic timescale or a stage in chronostratigraphy, being a division of the Pleistocene Epoch within the ongoing Quaternary Period. The ...

epochs. The Irvingtonian is preceded by the

Blancan The Blancan 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 4,750,000 to 1,806,000 years Before Present, BP, a period of .

and followed by the

Rancholabrean The Rancholabrean North American Land Mammal Age on the geologic timescale is the North American faunal stage according to the North American Land Mammal Ages chronology (NALMA), typically set from less than 240,000 years to 11,000 years BP, a p ...

NALMA The North American land mammal ages (NALMA) establishes a geologic timescale for North American fauna beginning during the Late Cretaceous and continuing through to the present. These periods are referred to as ages or intervals (or stages when ref ...

stages. The Irvingtonian can be further divided into substages: *Irvingtonian I - approximately 1.9 MA TO 0.85 MA *Irvingtonian II - approximately 0.85 MA TO 0.4 MA *Irvingtonian III - approximately 0.4 MA TO 0.25 MA The beginning of the Irvingtonian is defined by the first appearance of ''

Mammuthus A mammoth is any species of the extinct elephantid genus ''Mammuthus'', one of the many genera that make up the order of trunked mammals called proboscideans. The various species of mammoth were commonly equipped with long, curved tusks and, i ...

'' south of 55° N in North America, and the beginning of the succeeding Rancholabrean is defined by the first appearance of ''

Bison Bison are large bovines in the genus ''Bison'' (Greek: "wild ox" (bison)) within the tribe Bovini. Two extant and numerous extinct species are recognised. Of the two surviving species, the American bison, ''B. bison'', found only in North Ame ...

''. In South America, it chronologically overlaps with the

Uquian The Uquian age is a period of geologic time (3.0–1.5 Ma) within the Pliocene and Pleistocene epochs of the Neogene used more specifically with South American Land Mammal Ages. It follows the Montehermosan and precedes the Ensenadan The Ensenad ...

(partial),

Ensenadan The Ensenadan age is a period of geologic time (1.2–0.8 Ma) within the Early Pleistocene epoch of the Quaternary The Quaternary ( ) is the current and most recent of the three periods of the Cenozoic Era in the geologic time scale of the ...

, and

Lujanian The Lujanian age is a South American land mammal age within the Pleistocene and Holocene epochs of the Neogene, from 0.8–0.011 Ma or 800–11 tya. It follows the Ensenadan. The age is usually divided into the middle Pleistocene Bonaerian stag ...

South American Land Mammal Ages The South American land mammal ages (SALMA) establish a geologic timescale for prehistoric South American fauna beginning 64.5 Ma during the Paleocene and continuing through to the Late Pleistocene (0.011 Ma). These periods are referred to as age ...

Fauna

Notable mammals

Artiodactyla The even-toed ungulates (Artiodactyla , ) are ungulates—hoofed animals—which bear weight equally on two (an even number) of their five toes: the third and fourth. The other three toes are either present, absent, vestigial, or pointing poster ...

- even-toed ungulates * ''

Platygonus ''Platygonus'' ("flat head" in reference to the straight shape of the forehead) is an extinct genus of herbivorous peccaries of the family Tayassuidae, endemic to North and South America from the Miocene through Pleistocene epochs (10.3 million ...

'', peccaries * ''

Titanotylopus ''Titanotylopus'' is an extinct genus of terrestrial herbivore in the family Camelidae, endemic to North America from the late Hemphillian stage of the Miocene through the Irvingtonian stage of the Pleistocene. It was one of the last survivin ...

'', camels

Carnivora Carnivora is a Clade, monophyletic order of Placentalia, placental mammals consisting of the most recent common ancestor of all felidae, cat-like and canidae, dog-like animals, and all descendants of that ancestor. Members of this group are f ...

- carnivores * ''

Borophagus ''Borophagus'' ("gluttonous eater") is an extinct genus of the subfamily Borophaginae, a group of canids endemic to North America from the Middle Miocene epoch through the Early Pleistocene epoch 12—1.8 Mya. Evolution ''Borophagus'', like o ...

'', bone-crushing dogs * ''

Canis ''Canis'' is a genus of the Caninae which includes multiple extant species, such as wolves, dogs, coyotes, and golden jackals. Species of this genus are distinguished by their moderate to large size, their massive, well-developed skulls and den ...

'', wolves * ''

Chasmaporthetes ''Chasmaporthetes'', also known as hunting or running hyena, is an extinct genus of hyenas distributed in Eurasia, North America, and Africa during the Pliocene-Pleistocene epochs, living from 4.9 million to 780,000 years ago, existing for about ...

'', hyenas *''

Hesperocyoninae The extinct Hesperocyoninae are one of three subfamilies found within the canid family. The other two canid subfamilies are the extinct Borophaginae and extant Caninae. Taxonomic history Hesperocyoninae are basal canids that gave rise to th ...

'', dog-like carnivores *''

Machairodontinae Machairodontinae is an extinct subfamily of carnivoran mammals of the family Felidae (true cats). They were found in Asia, Africa, North America, South America, and Europe from the Miocene to the Pleistocene, living from about 16 million until ...

'', saber-toothed cats *''

Lynx A lynx is a type of wild cat. Lynx may also refer to: Astronomy * Lynx (constellation) * Lynx (Chinese astronomy) * Lynx X-ray Observatory, a NASA-funded mission concept for a next-generation X-ray space observatory Places Canada * Lynx, Ontar ...

'', lynxes, bobcats *''

Ursus Ursus is Latin for bear. It may also refer to: Animals * ''Ursus'' (mammal), a genus of bears People * Ursus of Aosta, 6th-century evangelist * Ursus of Auxerre, 6th-century bishop * Ursus of Solothurn, 3rd-century martyr * Ursus (''praefectus ...

'', bears

Lagomorpha The lagomorphs are the members of the taxonomic order Lagomorpha, of which there are two living families: the Leporidae (hares and rabbits) and the Ochotonidae (pikas). The name of the order is derived from the Ancient Greek ''lagos'' (λαγ� ...

- lagomorphs * ''

Hypolagus ''Hypolagus'' is an extinct genus of lagomorph, first recorded in the Hemingfordian (early to middle Miocene) of North America. It entered Asia during the early Turolian and spread to Europe not much later, where it survived until the Middle Pl ...

'', rabbits Perissodactyla - odd-toed ungulates * ''

Nannippus ''Nannippus'' is an extinct genus of three-toed horse endemic to North America during the Miocene through Pleistoceneabout 13.3—1.8 million years ago (Mya), living around 11.5 million years. This ancient species of three-toed horse grew up to 3 ...

'', horses * ''

Plesippus ''Plesippus'' is a genus of extinct horse from the Pleistocene of North America. Although commonly seen as a subgenus of ''Equus'' recent cladistic analysis considers it a distinct genus. Species Two species are recognized by Barron et al. (201 ...

'', horses - may belong in '' Equus'' Proboscidea - elephants *''

Elephantidae Elephantidae is a family of large, herbivorous proboscidean mammals collectively called elephants and mammoths. These are terrestrial large mammals with a snout modified into a trunk and teeth modified into tusks. Most genera and species in the ...

'', mammoths *''

Mammutidae Mammutidae is an extinct family of proboscideans that appeared during the Oligocene epoch and survived until the start of the Holocene. The family was first described in 1922, classifying fossil specimens of the type genus ''Mammut'' ( masto ...

'', mastodons * ''

Rhynchotherium ''Rhynchotherium'' is an extinct genus of proboscidea endemic to North America and Central America during the Miocene through Pliocene from 13.650 to 3.6 Ma, living for approximately . This gomphothere had two tusks and may have evolved from ...

'', gomphotheres * '' Stegomastodon'', gomphotheres

Rodent Rodents (from Latin , 'to gnaw') are mammals of the order Rodentia (), which are characterized by a single pair of continuously growing incisors in each of the upper and lower jaws. About 40% of all mammal species are rodents. They are na ...

ia - rodents * '' Paenemarmota'', giant marmots

Notable birds

Charadriiformes Charadriiformes (, from ''Charadrius'', the type genus of family Charadriidae) is a diverse order of small to medium-large birds. It includes about 390 species and has members in all parts of the world. Most charadriiform birds live near water an ...

* unknown scolopacid (archaic

calidrid ''Calidris'' is a genus of Arctic-breeding, strongly migratory wading birds in the family Scolopacidae. These birds form huge mixed flocks on coasts and estuaries in winter. They are the typical "sandpipers", small to medium-sized, long-winged ...

turnstone Turnstones are two bird species that comprise the genus ''Arenaria'' in the family Scolopacidae. They are closely related to calidrid sandpipers and might be considered members of the tribe Calidriini. The genus ''Arenaria'' was introduced by t ...

?)Wetmore (1937)

Falconiformes The order Falconiformes () is represented by the extant family Falconidae (falcons and caracaras) and a handful of enigmatic Paleogene species. Traditionally, the other bird of prey families Cathartidae (New World vultures and condors), Sagitt ...

- diurnal raptors * '' Falco'' sp., a falconFeduccia (1970)

Passeriformes A passerine () is any bird of the order Passeriformes (; from Latin 'sparrow' and '-shaped'), which includes more than half of all bird species. Sometimes known as perching birds, passerines are distinguished from other orders of birds by t ...

* unknown

corvid Corvidae is a Cosmopolitan distribution, cosmopolitan family (biology), family of oscine passerine birds that contains the crows, ravens, rook (bird), rooks, jackdaws, jays, magpies, treepies, choughs, and nutcracker (bird), nutcrackers. In coll ...

(archaic

magpie Magpies are birds of the Corvidae family. Like other members of their family, they are widely considered to be intelligent creatures. The Eurasian magpie, for instance, is thought to rank among the world's most intelligent creatures, and is one ...

References

{{Quaternary Footer Pleistocene life Calabrian (stage) Middle Pleistocene Pleistocene animals of North America Pleistocene California