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{{paleogene}}
The
Paleocene or
Palaeocene, the "early recent", is a geologic epoch that lasted from 65.5 ± 0.3 Ma to 55.8 ± 0.2 Ma (million years ago). It is the first epoch of the Palaeogene Period in the modern
CenozoicThe Cenozoic Era The Cenozoic (also Cænozoic or Cainozoic) Era The Cenozoic (also Cænozoic or Cainozoic) Era (meaning "new life" (Greek (kainos), "new", and (zoe), "life"), is the most recent of the three classic geological eras and covers the period from 65.5 million years ago to the...
era. As with most other older geologic periods, the
strataIn geology and related fields, a stratum is a layer of rock or soil with internally consistent characteristics that distinguishes it from contiguous layers. Each layer is generally one of a number of parallel layers that lie one upon another, laid down by natural forces. They may extend over...
that define the epoch's beginning and end are well identified but the exact date of the end is uncertain.
The Paleocene epoch immediately followed the mass
extinction eventAn extinction event is a sharp decrease in the number of species in a relatively short period of time. Mass extinctions affect most major taxonomic groups present at the time — birds, mammals, reptiles, amphibians, fish, invertebrates and other simpler life forms...
at the end of the
CretaceousThe Cretaceous , Latin language for "chalky", usually abbreviated K for its German translation Kreide , is a geologic period and system from circa to million years ago . In the geologic timescale, the Cretaceous follows on the Jurassic period and is followed by the Paleogene period of the...
, known as the K-T boundary (
CretaceousThe Cretaceous , Latin language for "chalky", usually abbreviated K for its German translation Kreide , is a geologic period and system from circa to million years ago . In the geologic timescale, the Cretaceous follows on the Jurassic period and is followed by the Paleogene period of the...
-
TertiaryThe Tertiary is a term for a geologic period 65 million to 2.588 million years ago. The Tertiary covered the time span between the superseded Secondary period and the Quaternary...
), which marks the demise of the
dinosaur{{Otheruses}}{{pp-semi-protected|small=yes}}{{Otheruses}}{{pp-semi-protected|small=yes}}{{Taxobox|name = Dinosaurs|fossil_range = {{Fossil range|230|65|earliest=230|latest=0|PS=
Descendant taxon Aves survives to present.}}|image = field_dinos_2.jpg...
s (except their descendants, modern birds) and much other
faunaFauna is all of the animal life of any particular region or time. The corresponding term for plants is flora.Zoologists and paleontologists use fauna to refer to a typical collection of animals found in a specific time or place, e.g...
and
floraIn botany, flora has two meanings. The first meaning, flora of an area or of time period, refers to all plant life occurring in an area or time period, especially the naturally occurring or indigenous plant life...
. The die-off of the dinosaurs left unfilled ecological niches worldwide, and the name "Paleocene" comes from Greek and refers to the "old(er)" ({{Polytonic|παλαιός}},
palaios) – "new" ({{Polytonic|καινός}},
kainos) fauna that arose during the epoch, before modern
mammalMammals are a class of vertebrate animals whose females are characterized by the possession of mammary glands while both males and females are characterized by sweat glands, hair, three middle ear bones used in hearing, and a neocortex region in the brain.Mammals are divided into three main...
ian
ordersLinnaean taxonomy is either# the particular classification of Linnaeus, as set forth in his Systema Naturae and subsequent works...
emerged in the
EoceneThe Eocene epoch, lasting from 55.8 ± 0.2 to 33.9 ± 0.1 Ma , is a major division of the geologic timescale and the second epoch of the Palaeogene period in the Cenozoic era. The Eocene spans the time from the end of the Paleocene epoch to the beginning of the Oligocene epoch. The start of the...
.
Boundaries and subdivisions
The K-T boundary that marks the separation between Cretaceous and Paleocene is visible in the geological record of much of the Earth by a discontinuity in the fossil fauna, with high
iridiumIridium is the chemical element with atomic number 77, and is represented by the symbol Ir. A very hard, brittle, silvery-white transition metal of the platinum family, iridium is the second densest element and is the most corrosion-resistant metal, even at temperatures as high as 2000 °C...
levels. There is also fossil evidence of abrupt changes in flora and fauna. There is some evidence that a substantial but very short-lived climatic change may have happened in the very early decades of the Paleocene. There are several theories about the cause of the K-T extinction event, with most evidence supporting the impact of a 10 km
diameterIn geometry, a diameter of a circle is any straight line segment that passes through the center of the circle and whose endpoints are on the circle. The diameters are the longest chords of the circle...
asteroidthumb|260px|right|[[253 Mathilde]], a [[C-type asteroid]] measuring about across. Photograph taken in 1997 by the [[NEAR Shoemaker]] probe.Asteroids, sometimes called minor planets or planetoids, are small Solar System bodies in orbit around the Sun, especially in the inner Solar System; they are...
forming the buried
Chicxulub CraterThe Chicxulub crater is an ancient impact crater buried underneath the Yucatán Peninsula in Mexico. Its center is located near the town of Chicxulub, after which the crater is named — as well as the rough translation of the Mayan name, "the tail of the devil." The crater is more than...
on the coast of
YucatanYucatán is one of the 31 states of Mexico, located on the north of the Yucatán Peninsula. The Yucatan peninsula includes three states: Yucatán, Campeche, and Quintana Roo; all three modern states were formerly part of the larger historic state of Yucatán in the 19th century. The state capital of...
,
MexicoThe United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...
.
The end of the Paleocene (55.5/54.8 Ma) was marked by one of the most significant periods of global change during the Cenozoic. The
Paleocene-Eocene Thermal MaximumThe Paleocene/Eocene boundary, , was marked by the most rapid and significant climatic disturbance of the Cenozoic Era. A sudden global warming event, leading to the Paleocene–Eocene Thermal Maximum , is associated with changes in oceanic and atmospheric...
upset oceanic and atmospheric circulation and led to the extinction of numerous deep-sea benthic
foraminiferaThe Foraminifera, or forams for short, are a large group of amoeboid protists with reticulating pseudopods, fine strands of cytoplasm that branch and merge to form a dynamic net. They typically produce a test, or shell, which can have either one or multiple chambers, some becoming quite elaborate...
and a major turnover in mammals on land.
The Paleocene is divided into three stages, from youngest to oldest:
| Thanetian The Thanetian is, in the ICS' Geologic timescale, the latest age or uppermost stratigraphic stage of the Paleocene epoch or series. It spans the time between 58.7 ± 0.2 Ma and 55.8 ± 0.2 Ma . The Thanetian is preceded by the Selandian age and followed by the Ypresian age...
|
(58.7 ± 0.2 – 55.8 ± 0.2 Ma) |
| Selandian The Selandian is in the geologic timescale an age or stage in the Paleocene. It spans the time between 61.7 ± 0.2 Ma and 58.7 ± 0.2 Ma . It is preceded by the Danian and followed by the Thanetian...
|
(61.7 ± 0.2 – 58.7 ± 0.2 Ma) |
| Danian The Danian is the oldest age or lowermost stage of the Paleocene epoch or series, the Paleogene period or system and the Cenozoic era or erathem. The beginning of the Danian age is at the Cretaceous-Tertiary extinction event 65.5 ± 0.3 Ma...
|
(65.5 ± 0.3 – 61.7 ± 0.2 Ma) |
Additionally, the Paleocene is divided into six Mammal Paleogene zones.
Climate
The early Paleocene was cooler and dryer than the preceding Cretaceous, though temperatures rose sharply during the Paleocene–Eocene Thermal Maximum. The climate became warm and humid worldwide towards the Eocene boundary, with subtropical vegetation growing in
GreenlandGreenland is an autonomous constituent country within the Kingdom of Denmark located between the Arctic and Atlantic Oceans, east of the Canadian Arctic Archipelago...
and
PatagoniaPatagonia is a geographic region containing the southernmost portion of South America. Located in Argentina and Chile, it comprises the southernmost portion of the Andes mountains to the west and south, and plateaux and low plains to the east. The name Patagonia comes from the word patagón used by...
, crocodiles swimming off the coast of Greenland, and early primates evolving in tropical palm forests of northern Wyoming. The Earth's poles were cool and temperate;
North AmericaNorth America is the northern continent of the Americas, situated in the Earth's northern hemisphere and in the western hemisphere. It is bordered on the north by the Arctic Ocean, on the east by the North Atlantic Ocean, on the southeast by the Caribbean Sea, and on the west by the North Pacific...
,
EuropeEurope is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally divided from Asia to its east by the water divide of the Ural Mountains, the Ural River, the Caspian Sea, the Caucasus Mountains , and the Black Sea to the southeast...
,
AustraliaAustralia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the continental mainland , the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans...
and southern
South AmericaSouth America is the southern continent of the Americas, situated entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere...
were warm and temperate; equatorial areas had tropical climates; and north and south of the
equatorThe equator is the intersection of the Earth's surface with the plane perpendicular to the Earth's axis of rotation and containing the Earth's center of mass. In simpler language, it is an imaginary line on the Earth's surface equidistant from the North Pole and South Pole that divides the Earth...
ial areas, climates were hot and arid.
Paleogeography
In many ways, the Paleocene continued processes that had begun during the late Cretaceous Period. During the Paleocene, the
continentA continent is one of several large landmasses on Earth. They are generally identified by convention rather than any strict criterion, with seven regions commonly regarded as continents – they are : Asia, Africa, North America, South America, Antarctica, Europe, and Australia.Plate tectonics is...
s continued to drift toward their present positions.
SupercontinentIn geology, a supercontinent is a landmass comprising more than one continental core, or craton. The assembly of cratons and accreted terranes that form Eurasia qualifies as a supercontinent today.-History:...
LaurasiaLaurasia was a supercontinent that most recently existed as a part of the split of the Pangaea supercontinent in the late Mesozoic era. It included most of the landmasses which make up today's continents of the northern hemisphere, chiefly Laurentia , Baltica, Siberia, Kazakhstania, and the North...
had not yet separated into three continents -
EuropeEurope is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally divided from Asia to its east by the water divide of the Ural Mountains, the Ural River, the Caspian Sea, the Caucasus Mountains , and the Black Sea to the southeast...
and
GreenlandGreenland is an autonomous constituent country within the Kingdom of Denmark located between the Arctic and Atlantic Oceans, east of the Canadian Arctic Archipelago...
were still connected,
North AmericaNorth America is the northern continent of the Americas, situated in the Earth's northern hemisphere and in the western hemisphere. It is bordered on the north by the Arctic Ocean, on the east by the North Atlantic Ocean, on the southeast by the Caribbean Sea, and on the west by the North Pacific...
and
AsiaAsia is the world's largest and most populous continent, located in the eastern and northern hemispheres. It covers 8.6% of the earth's total surface area and with approximately 4 billion people, it hosts 60% of the world's current human population.Asia is traditionally defined as part of the...
were still intermittently joined by a land bridge, while Greenland and North America were beginning to separate. The
Laramide orogenyThe Laramide orogeny was a period of mountain building in western North America, which started in the Late Cretaceous, 70 to 80 million years ago, and ended 35 to 55 million years ago. The exact duration and ages of beginning and end of the orogeny are in dispute, as is the cause. The Laramide...
of the late Cretaceous continued to uplift the
Rocky MountainsThe Rocky Mountains are a major mountain range in western North America. The Rocky Mountains stretch more than from the northernmost part of British Columbia, in Canada, to New Mexico, in the United States. The range's highest peak is Mount Elbert in Colorado at above sea level...
in the American west, which ended in the succeeding epoch.
South and North America remained separated by equatorial seas (they joined during the
NeogeneThe Neogene is a geologic period and system starting 23.03 ± 0.05 million years ago and lasting either until today or ending 2.588 million years ago with the beginning of the Quaternary. The Neogene Period follows the Paleogene Period of the Cenozoic Era...
); the components of the former southern supercontinent Gondwanaland continued to split apart, with
AfricaAfrica is the world's second-largest and second most-populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area. With a billion people in 61 territories, it accounts for about 14.8% of the...
, South America,
Antarctica| style="border-top:solid 1px #ccd2d9; padding:0.4em 1em 0.4em 0; vertical-align:top;" | 14,000,000 km
2 280,000 km
2 13,720,000 km
2 |-! style="border-top: solid 1px #ccd2d9; padding: 0.4em 1em 0.4em 0; vertical-align: top;...
and
AustraliaAustralia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the continental mainland , the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans...
pulling away from each other. Africa was heading north towards
EuropeEurope is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally divided from Asia to its east by the water divide of the Ural Mountains, the Ural River, the Caspian Sea, the Caucasus Mountains , and the Black Sea to the southeast...
, slowly closing the
Tethys OceanThe Tethys Ocean was an ocean that existed between the continents of Gondwana and Laurasia during the Mesozoic era before the opening of the Indian Ocean.-Modern theory:...
, and
IndiaIndia, officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country, and the most populous democracy in the world. Bounded by the Indian Ocean on the south, the Arabian Sea on the west, and the Bay of Bengal...
began its migration to Asia that would lead to a tectonic collision and the formation of the
HimalayasThe Himalaya Range or Himalayas for short , meaning "abode of snow", is a mountain range in Asia, separating the Indian subcontinent from the Tibetan Plateau...
.
The inland seas in North America (
Western Interior SeawayThe Western Interior Seaway, also called the Cretaceous Seaway, the Niobraran Sea, and the North American Inland Sea, was a huge inland sea that split the continent of North America into two halves during most of the mid and late Cretaceous Period.-Origin and geology:The Seaway was created as the...
) and Europe had receded by the beginning of the Paleocene, making way for new land-based flora and fauna.
Flora
Terrestrial Paleocene strata immediately overlying the K-T boundary is in places marked by a "
fernA fern is any one of a group of about 20,000 species of plants classified in the phylum or division Pteridophyta, also known as Filicophyta. The group is also referred to as Polypodiophyta, or Polypodiopsida when treated as a subdivision of tracheophyta...
spike": a bed especially rich in fern fossils. Ferns are often the first species to colonize areas damaged by forest fires; thus the fern spike may indicate post-
Chicxulub CraterThe Chicxulub crater is an ancient impact crater buried underneath the Yucatán Peninsula in Mexico. Its center is located near the town of Chicxulub, after which the crater is named — as well as the rough translation of the Mayan name, "the tail of the devil." The crater is more than...
devastation.
In general, the Paleocene is marked by the development of modern plant species.
CactiA cactus is any member of the plant family Cactaceae, native to the Americas. They are often used as ornamental plants, but some are also crop plants. Cacti are grown for protection of property from wild animals, as well as many other uses...
and palm trees appeared. Paleocene and later plant
fossilFossils are the preserved remains or traces of animals, plants, and other organisms from the remote past. The totality of fossils, both discovered and undiscovered, and their placement in fossiliferous rock formations and sedimentary layers is known as the fossil record...
s are generally attributed to modern
generaIn biology, a genus is a taxonomic unit used in the classification of living and fossil organisms. The term comes from Latin genus "descent, family, type, gender" , cognate with – genos, "race, stock, kin" ..In addition, genus is a taxonomic rank in the hierarchy In biology, a genus (plural:...
or to closely related taxa.
The warm temperatures worldwide gave rise to thick tropical, sub-tropical and deciduous forest cover around the globe (the first recognizably modern rain forests) with ice-free polar regions covered with coniferous and deciduous trees. With no large grazing dinosaurs to thin them, Paleocene forests were probably denser than those of the Cretaceous.
Flowering plants (angiosperms), first seen in the Cretaceous, continued to develop and proliferate, and along with them coevolved the insects that fed on these plants and pollinated them.
Mammals
Mammals had first appeared in the
TriassicThe Triassic is a geologic period and system that extends from about 251 to 199 Ma . As the first period of the Mesozoic Era, the Triassic follows the Permian and is followed by the Jurassic. Both the start and end of the Triassic are marked by major extinction events...
, evolving from advanced cynodonts, and developed alongside the dinosaurs, exploiting ecological niches untouched by the larger and more famous
MesozoicThe Mesozoic Era is one of three geologic eras of the Phanerozoic eon. The division of time into eras dates back to Giovanni Arduino, in the 18th century, although his original name for the era now called the "Mesozoic" was "Secondary" The Mesozoic Era is one of three geologic eras of the...
animals: in the insect-rich forest underbrush and high up in the trees. These smaller mammals (as well as
birdBirds are winged, bipedal, endothermic , vertebrate animals that lay eggs. There are around 10,000 living species, making them the most numerous tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Birds range in size from the Bee Hummingbird to the ...
s,
reptileReptiles, or members of the class Reptilia, are air-breathing, generally "cold-blooded" amniotes that generally have skin covered in scales or scutes. They are tetrapods and lay amniote eggs, whose embryos are surrounded by the amnion membrane...
s,
amphibianAmphibians , such as frogs, toads, salamanders, newts, and caecilians, are ectothermic animals that metamorphose from a juvenile water-breathing form, to an adult air-breathing form. Though amphibians typically have four limbs, the Caecilians are notable for being limbless. Unlike other land...
s, and
insectInsects are arthropods, having a hard exoskeleton, a three-part body , three pairs of jointed legs, compound eyes, and two antennae. They are the most diverse group of animals on the planet and include more than a million species that are already described. Insects represent more than half of all...
s) survived the mass extinction at the end of the Cretaceous which wiped out the dinosaurs, and mammals diversified and spread throughout the world.
While early mammals were small nocturnal animals that mostly ate soft plant material and small animals such as insects, the demise of the dinosaurs and the beginning of the Paleocene saw mammals growing bigger and occupying a wider variety of
ecological nicheIn ecology, a niche is a term describing the relational position of a species or population in its ecosystem to each other; e.g. a dolphin could potentially be in another ecological niche from one that travels in a different school if the members of these schools utilize significantly different...
s. Ten million years after the death of the dinosaurs, the world was filled with rodent-like mammals, medium sized mammals scavenging in forests, and large herbivorous and carnivorous mammals hunting other mammals, birds, and reptiles.
Fossil evidence from the Paleocene is scarce, and there is relatively little known about mammals of the time. Because of their small size (constant until late in the epoch) early mammal bones are not well-preserved in the fossil record, and most of what we know comes from fossil teeth (a much tougher substance), and only a few skeletons.
Paleocene mammals did not yet have specialized teeth or limbs, and their
brain to body mass ratioBrain-to-body weight ratio is a rough estimate of the possible intelligence of an organism....
s were quite low; compared to later forms, they are considered primitive, or archaic. It was not until the
EoceneThe Eocene epoch, lasting from 55.8 ± 0.2 to 33.9 ± 0.1 Ma , is a major division of the geologic timescale and the second epoch of the Palaeogene period in the Cenozoic era. The Eocene spans the time from the end of the Paleocene epoch to the beginning of the Oligocene epoch. The start of the...
, 55 Ma, that true modern mammals developed.
Mammals of the Paleocene include:
- Monotreme
Monotremes are mammals that lay eggs instead of giving birth to live young like marsupials and placental mammals ....
s: three species of monotremes have survived to modern times: the PlatypusThe Platypus is a semi-aquatic mammal endemic to eastern Australia, including Tasmania. Together with the four species of echidna, it is one of the five extant species of monotremes, the only mammals that lay eggs instead of giving birth to live young...
, and two species of EchidnaEchidnas , also known as spiny anteaters, are four extant mammal species belonging to the Tachyglossidae family of the monotremes, an order of egg laying mammals. Together with the Platypus, they are the only surviving members of that order comprising the only extant mammals that lay eggs...
s. Monotrematum sudamericanum lived during the Paleocene.
- Marsupials: modern kangaroo
A kangaroo is a marsupial from the family Macropodidae . In common use the term is used to describe the largest species from this family, especially those of genus Macropus, Red Kangaroo, Antilopine Kangaroo, Eastern and Western Grey Kangaroo...
s are marsupials, characterized by giving birth to embryonic babies, who crawl into the mother's pouch and suckle until they are developed. The Bolivian Pucadelphys andinusPucadelphys andinus was a marsupial species belonging to the family Didelphidae.Fossils of Pucadelphys have been found at Tiupampa ....
is a Paleocene example.
- Multituberculates: the only major branch of mammals to go extinct since the K-T boundary, this rodent-like grouping includes the Paleocene Ptilodus
Ptilodus is a genus of mammals from the extinct order of Multituberculata, and lived during the Paleocene in North America.Ptilodus was a relatively large multituberculate of in length, which is about the same size as a squirrel...
.
- Placentals: this grouping of mammals became the most diverse and the most successful. Members include primates, plesiadapids, and hoofed ungulates, including the condylarth
Condylarthra is an order of extinct placental mammals known primarily from the Paleocene and Eocene epochs. Condylarths are among the most characteristic Paleocene mammals and they illustrate the evolutionary level of the Paleocene mammal fauna....
s and the carnivorous mesonychidMesonychia are an extinct order of medium to large-sized carnivorous mammals that were closely related to artiodactyls , and to cetaceans...
s.
Reptiles
Because of the climatic conditions of the Paleocene, reptiles were more widely distributed over the globe than at present. Among the sub-tropical reptiles found in North America during this epoch are champsosaurs (aquatic reptiles that resemble modern
gharialThe gharial , sometimes called the Indian gavial or gavial, is one of two surviving members of the family Gavialidae, a long-established group of crocodile-like reptiles with long, narrow jaws. It is a critically endangered species...
s),
crocodiliaCrocodilia is an order of large reptiles that appeared about 84 million years ago in the late Cretaceous Period . They are the closest living relatives of birds, as the two groups are the only known survivors of the Archosauria...
, soft-shelled turtles, palaeophi snakes,
varanid lizardsVaranidae is a group of lizards of the superfamily Varanoidea. The family is a group of carnivorous lizards which includes the heaviest living lizard, the Komodo dragon, and the crocodile monitor which is the longest lizard in the world. Varanidae contains the living genus Varanus and a number of...
, and
Protochelydra zangerli (similar to modern
snapping turtlesThere are two extant species of the family Chelydridae: Chelydra serpentina, the Common Snapping Turtle, and its larger relative Macrochelys temminckii, the Alligator Snapping Turtle...
).
Examples of champsosaurs of the Paleocene include
ChampsosaurusChampsosaurus is an extinct genus of diapsid reptile belonging to the order Choristodera. It grew to about 1.50 m long.Champsosaurus resembled a gharial and, like gharials, hunted in rivers and swamps, catching fish with its long, tooth-lined jaws...
gigas, the largest champsosaur ever discovered. This creature was unusual among Paleocene reptiles in that
C. gigas became larger than its known
MesozoicThe Mesozoic Era is one of three geologic eras of the Phanerozoic eon. The division of time into eras dates back to Giovanni Arduino, in the 18th century, although his original name for the era now called the "Mesozoic" was "Secondary" The Mesozoic Era is one of three geologic eras of the...
ancestors:
C. gigas is more than twice the length of the largest Cretaceous specimens (3 meters versus 1.5 meters). Reptiles as a whole decreased in size after the K-T event. Champsosaurs declined towards the end of the Paleocene and became extinct during the
MioceneThe Miocene is a geological epoch of the Neogene period and extends from about 23.03 to 5.33 million years before the present . The Miocene was named by Sir Charles Lyell. Its name comes from the Greek words and and means "less recent" because it has 18% fewer modern sea invertebrates than the...
.
Examples of Paleocene crocodylians are
BorealosuchusBorealosuchus is an extinct genus of crocodilian that lived from the Late Cretaceous to the Eocene in North America. It was named by Chris Brochu in 1997 for several species that had been assigned to Leidyosuchus. The species assigned to it are:B...
(formerly
LeidyosuchusLeidyosuchus is an extinct genus of alligatorid from the Late Cretaceous of Alberta. It was named in 1907 by Lawrence Lambe, and the type species is L. canadensis. It is known from a number of specimens from the middle Campanian age Dinosaur Park Formation...
)
formidabilis, the
apex predatorApex predators is a predator that has virtually no predators of its own, residing at the top of its food chain...
and the largest animal of the Wannagan Creek fauna, and the alligatorid
WannaganosuchusWannaganosuchus is an extinct genus of small alligatorid...
.
Non-avian dinosaurs may have survived to some extent into the early Danian stage of the Paleocene Epoch circa 64.5 Mya. The controversial evidence for such is a hadrosaur leg bone found from Paleocene strata in
New MexicoNew Mexico is a state located in the southwestern region of the United States. Inhabited by Native American populations for many centuries, it has also been part of the Imperial Spanish viceroyalty of New Spain, part of Mexico, and a U.S. territory. Among U.S...
; but such stray late forms may be
derived fossilA derived fossil is a fossil found in rock made later than when the fossilized animal or plant died: it happens when a hard fossil is freed from a soft rock formation by erosion and redeposited in a currently forming sediment deposit. Another name for such a specimen is a reworked fossil....
s.
Birds
Birds began to re-diversify during the epoch, occupying new niches. Most modern bird types had appeared by mid-Cenozoic, including
perching birdA passerine is a bird of the order Passeriformes, which includes more than half of all bird species. Sometimes known as perching birds or, less accurately, as songbirds, the passerines form one of the most diverse terrestrial vertebrate orders:...
s,
craneCranes are large, long-legged and long-necked birds of the order Gruiformes, and family Gruidae. There are fifteen species. Unlike the similar-looking but unrelated herons, cranes fly with necks outstretched, not pulled back...
s,
hawkThe term hawk can be used in several ways:* In strict usage in Europe and Asia, to mean any of the species in the subfamily Accipitrinae, which comprises the genera Accipiter, Micronisus, Melierax, Urotriorchis and Megatriorchis. The large and widespread Accipiter genus includes goshawks,...
s,
pelicanA pelican is a large water bird with a distinctive pouch under the beak, belonging to the bird family Pelecanidae.Along with the darters, cormorants, gannets, boobies, frigatebirds, and tropicbirds, pelicans make up the order Pelecaniformes. Modern pelicans are found on all continents except...
s,
heronThe herons are wading birds in the Ardeidae family. There are 64 recognised species in this family. Some are called egrets or bitterns instead of herons....
s,
owlThe Owls are the order Strigiformes, comprising 200 birds of prey, species. Most are solitary, and nocturnal, with some exceptions . Owls hunt mostly small mammals, insects, and other birds, though a few species specialize in hunting fish. They are found in all regions of the Earth except...
s,
duckDuck is the common name for a number of species in the Anatidae family of birds. The ducks are divided between several subfamilies listed in full in the Anatidae article; they do not represent a monophyletic group but a form taxon, since swans and geese are not considered ducks...
s,
pigeonPigeons and doves constitute the family Columbidae within the order Columbiformes, which include some 300 species of near passerine birds. In general parlance the terms "dove" and "pigeon" are used somewhat interchangeably...
s,
loonThe loons or divers are a group of aquatic birds found in many parts of North America and northern Eurasia...
s, and
woodpeckerWoodpeckers are near passerine birds of the order Piciformes. They are one subfamily in the family Picidae, which also includes the piculets and wrynecks. They are found worldwide and include about 180 species....
s.
Large carnivorous flightless birds (also called
Terror BirdsPhorusrhacids , or terror birds, were a family of large carnivorous flightless birds that were the dominant predators in South America during the Cenozoic, 62–2 million years ago. They were roughly 1–3 meters tall. Their closest modern-day relatives are believed to be the 80 cm-tall seriemas...
) have been found in late Paleocene fossils, including the fearsome
GastornisGastornis , is an extinct genus of large flightless bird that lived during the late Paleocene and Eocene periods of the Cenozoic. It was named in 1855, after Gaston Planté, who had discovered the first fossils in Argile Plastique formation deposits at Meudon near Paris...
in Europe.
In the late Paleocene, early owl types appeared, such as
OgygoptynxOgygoptynx is an extinct genus of owl from the Paleocene.-References:*Rich, Patricia Vickers & David J. Bohaska, 1981. The Ogygoptyngidae, a New Family of Owls from the Paleocene of North America. Alcheringa 5: 95-102....
in the
United StatesThe United States of America is a federal constitutional republic comprising fifty states and a federal district...
and
Berruornis in
FranceFrance , officially the French Republic , is a country located in Western Europe, with several overseas islands and territories located on other continents. Metropolitan France extends from the Mediterranean Sea to the English Channel and the North Sea, and from the Rhine to the Atlantic Ocean...
.
Oceans
Warm seas circulated throughout the world, including the poles. The earliest Paleocene featured a low diversity and abundance of marine life, but this trend reversed later in the epoch. Tropical conditions gave rise to abundant marine life, including
coral reefCoral reefs are aragonite structures produced by living organisms, found in marine waters containing few nutrients. In most reefs, the predominant organisms are stony corals, colonial cnidarians that secrete an exoskeleton of calcium carbonate...
s. With the demise of marine reptiles at the end of the Cretaceous,
sharkSharks are a type of fish with a full cartilaginous skeleton and a highly streamlined body. The earliest known sharks date from more than 420 million years ago, before the time of the dinosaurs....
s became the top predators. At the end of the Cretaceous, the ammonites and many species of
foraminiferaThe Foraminifera, or forams for short, are a large group of amoeboid protists with reticulating pseudopods, fine strands of cytoplasm that branch and merge to form a dynamic net. They typically produce a test, or shell, which can have either one or multiple chambers, some becoming quite elaborate...
became extinct.
Marine faunas also came to resemble modern faunas, with only the marine mammals and the Carcharhinid sharks missing.
External links
{{Commonscat|Paleocene}}
{{Cenozoic Footer}}
{{Paleogene Footer}}