135-466: See text Patia is a genus of butterflies in the subfamily Dismorphiinae . They are native to the Americas . This Pieridae -related article is a stub . You can help Misplaced Pages by expanding it . Butterfly Butterflies are winged insects from the lepidopteran suborder Rhopalocera , characterized by large, often brightly coloured wings that often fold together when at rest, and
270-631: A diapause (resting) stage, and the hatching may take place only in spring. Some temperate region butterflies, such as the Camberwell beauty , lay their eggs in the spring and have them hatch in the summer. Butterfly larvae, or caterpillars, consume plant leaves and spend practically all of their time searching for and eating food. Although most caterpillars are herbivorous, a few species are predators : Spalgis epius eats scale insects , while lycaenids such as Liphyra brassolis are myrmecophilous , eating ant larvae. Some larvae, especially those of
405-493: A butterfly cannot fly until the wings are unfolded. A newly emerged butterfly needs to spend some time inflating its wings with hemolymph and letting them dry, during which time it is extremely vulnerable to predators. The colourful patterns on many butterfly wings tell potential predators that they are toxic. Hence, the genetic basis of wing pattern formation can illuminate both the evolution of butterflies as well as their developmental biology . The colour of butterfly wings
540-570: A butterfly through metamorphosis has held great appeal to mankind. To transform from the miniature wings visible on the outside of the pupa into large structures usable for flight, the pupal wings undergo rapid mitosis and absorb a great deal of nutrients. If one wing is surgically removed early on, the other three will grow to a larger size. In the pupa, the wing forms a structure that becomes compressed from top to bottom and pleated from proximal to distal ends as it grows, so that it can rapidly be unfolded to its full adult size. Several boundaries seen in
675-710: A climate similar to the Pacific Northwest . On the Alaska North Slope , Metasequoia was the dominant conifer. Much of the diversity represented migrants from nearer the equator. Deciduousness was dominant, probably to conserve energy by retroactively shedding leaves and retaining some energy rather than having them die from frostbite. In south-central Alaska, the Chickaloon Formation preserves peat-forming swamps dominated by taxodiaceous conifers and clastic floodplains occupied by angiosperm–conifer forests. At
810-417: A common family. In some species, such as the great spangled fritillary , the eggs are deposited close to but not on the food plant. This most likely happens when the egg overwinters before hatching and where the host plant loses its leaves in winter, as do violets in this example. The egg stage lasts a few weeks in most butterflies, but eggs laid close to winter, especially in temperate regions, go through
945-611: A conspicuous, fluttering flight. The group comprises the superfamilies Hedyloidea (moth-butterflies in the Americas) and Papilionoidea (all others). The oldest butterfly fossils have been dated to the Paleocene , about 56 million years ago, though molecular likely originated in the Cretaceous . Butterflies have a four-stage life cycle , and like other holometabolous insects they undergo complete metamorphosis . Winged adults lay eggs on
1080-530: A defined deep-water thermocline (a warmer mass of water closer to the surface sitting on top of a colder mass nearer the bottom) persisting throughout the epoch. The Atlantic foraminifera indicate a general warming of sea surface temperature–with tropical taxa present in higher latitude areas–until the Late Paleocene when the thermocline became steeper and tropical foraminifera retreated back to lower latitudes. Early Paleocene atmospheric CO 2 levels at what
1215-597: A depth of about 1,000 m (3,300 ft). The Danian deposits are sequestered into the Aitzgorri Limestone Formation , and the Selandian and early Thanetian into the Itzurun Formation . The Itzurun Formation is divided into groups A and B corresponding to the two stages respectively. The two stages were ratified in 2008, and this area was chosen because of its completion, low risk of erosion, proximity to
1350-571: A few butterflies (e.g., harvesters ) eat harmful insects, and a few are predators of ants , while others live as mutualists in association with ants. Culturally, butterflies are a popular motif in the visual and literary arts. The Smithsonian Institution says "butterflies are certainly one of the most appealing creatures in nature". The Oxford English Dictionary derives the word straightforwardly from Old English butorflēoge , butter-fly; similar names in Old Dutch and Old High German show that
1485-444: A few species. Some butterflies have organs of hearing and some species make stridulatory and clicking sounds. Many species of butterfly maintain territories and actively chase other species or individuals that may stray into them. Some species will bask or perch on chosen perches. The flight styles of butterflies are often characteristic and some species have courtship flight displays. Butterflies can only fly when their temperature
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#17328907433031620-606: A hard-ridged outer layer of shell, called the chorion . This is lined with a thin coating of wax which prevents the egg from drying out before the larva has had time to fully develop. Each egg contains a number of tiny funnel-shaped openings at one end, called micropyles ; the purpose of these holes is to allow sperm to enter and fertilize the egg. Butterfly eggs vary greatly in size and shape between species, but are usually upright and finely sculptured. Some species lay eggs singly, others in batches. Many females produce between one hundred and two hundred eggs. Butterfly eggs are fixed to
1755-643: A higher rate than deciduous angiosperms as deciduous plants can become dormant in harsh conditions. In the Gulf Coast, angiosperms experienced another extinction event during the PETM, which they recovered quickly from in the Eocene through immigration from the Caribbean and Europe. During this time, the climate became warmer and wetter, and it is possible that angiosperms evolved to become stenotopic by this time, able to inhabit
1890-503: A leaf before eggs are laid on it. Many butterflies use chemical signals, pheromones ; some have specialized scent scales ( androconia ) or other structures ( coremata or "hair pencils" in the Danaidae). Vision is well developed in butterflies and most species are sensitive to the ultraviolet spectrum. Many species show sexual dimorphism in the patterns of UV reflective patches. Colour vision may be widespread but has been demonstrated in only
2025-416: A leaf with a special glue which hardens rapidly. As it hardens it contracts, deforming the shape of the egg. This glue is easily seen surrounding the base of every egg forming a meniscus. The nature of the glue has been little researched but in the case of Pieris brassicae , it begins as a pale yellow granular secretion containing acidophilic proteins. This is viscous and darkens when exposed to air, becoming
2160-547: A longer lifespan of several months as adults. The thorax of the butterfly is devoted to locomotion. Each of the three thoracic segments has two legs (among nymphalids , the first pair is reduced and the insects walk on four legs). The second and third segments of the thorax bear the wings. The leading edges of the forewings have thick veins to strengthen them, and the hindwings are smaller and more rounded and have fewer stiffening veins. The forewings and hindwings are not hooked together ( as they are in moths ) but are coordinated by
2295-441: A narrow range of temperature and moisture; or, since the dominant floral ecosystem was a highly integrated and complex closed-canopy rainforest by the middle Paleocene, the plant ecosystems were more vulnerable to climate change . There is some evidence that, in the Gulf Coast, there was an extinction event in the late Paleocene preceding the PETM, which may have been due to the aforementioned vulnerability of complex rainforests, and
2430-448: A necessity for their successful establishment. Many butterflies, such as the painted lady , monarch, and several danaine migrate for long distances. These migrations take place over a number of generations and no single individual completes the whole trip. The eastern North American population of monarchs can travel thousands of miles south-west to overwintering sites in Mexico . There is
2565-646: A reverse migration in the spring. It has recently been shown that the British painted lady undertakes a 9,000-mile round trip in a series of steps by up to six successive generations, from tropical Africa to the Arctic Circle — almost double the length of the famous migrations undertaken by monarch. Spectacular large-scale migrations associated with the monsoon are seen in peninsular India. Migrations have been studied in more recent times using wing tags and also using stable hydrogen isotopes . Butterflies navigate using
2700-412: A segmented palp. Adjoining these is the labium-hypopharynx which houses a tubular spinneret which is able to extrude silk. Caterpillars such as those in the genus Calpodes (family Hesperiidae) have a specialized tracheal system on the 8th segment that function as a primitive lung. Butterfly caterpillars have three pairs of true legs on the thoracic segments and up to six pairs of prolegs arising from
2835-424: A short time frame. The freezing temperatures probably reversed after three years and returned to normal within decades, sulfuric acid aerosols causing acid rain probably dissipated after 10 years, and dust from the impact blocking out sunlight and inhibiting photosynthesis would have lasted up to a year though potential global wildfires raging for several years would have released more particulates into
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#17328907433032970-435: A silken girdle may be spun to keep the pupa in a head-up position. Most of the tissues and cells of the larva are broken down inside the pupa, as the constituent material is rebuilt into the imago. The structure of the transforming insect is visible from the exterior, with the wings folded flat on the ventral surface and the two halves of the proboscis, with the antennae and the legs between them. The pupal transformation into
3105-746: A single formation (a stratotype ) identifying the lower boundary of the stage. In 1989, the ICS decided to split the Paleocene into three stages: the Danian, Selandian, and Thanetian. The Danian was first defined in 1847 by German-Swiss geologist Pierre Jean Édouard Desor based on the Danish chalks at Stevns Klint and Faxse , and was part of the Cretaceous, succeeded by the Tertiary Montian Stage. In 1982, after it
3240-665: A single generation, and a few in cold locations may take several years to pass through their entire life cycle. Butterflies are often polymorphic , and many species make use of camouflage , mimicry , and aposematism to evade their predators. Some, like the monarch and the painted lady , migrate over long distances. Many butterflies are attacked by parasites or parasitoids , including wasps , protozoans , flies , and other invertebrates, or are preyed upon by other organisms. Some species are pests because in their larval stages they can damage domestic crops or trees; other species are agents of pollination of some plants. Larvae of
3375-410: A time-compensated sun compass. They can see polarized light and therefore orient even in cloudy conditions. The polarized light near the ultraviolet spectrum appears to be particularly important. Many migratory butterflies live in semi-arid areas where breeding seasons are short. The life histories of their host plants also influence butterfly behaviour. Butterflies in their adult stage can live from
3510-528: A total of about 20,000 species. Traditionally, butterflies have been divided into the superfamilies Papilionoidea and the moth-like Hedyloidea . Recent work has discovered that Hedylidae, the only family within Hedyloidea, is nested within the Papilionoidea, meaning that Papilionoidea would be synonymous with Rhopalocera. The relationships between the rest of the 6 families are extremely well resolved, which
3645-470: A trend towards multivoltinism . Courtship is often aerial and often involves pheromones . Butterflies then land on the ground or on a perch to mate. Copulation takes place tail-to-tail and may last from minutes to hours. Simple photoreceptor cells located at the genitals are important for this and other adult behaviours. The male passes a spermatophore to the female; to reduce sperm competition, he may cover her with his scent, or in some species such as
3780-486: A tubular proboscis which is curled up at rest and expanded when needed to feed. The first and second maxillae bear palps which function as sensory organs. Some species have a reduced proboscis or maxillary palps and do not feed as adults. Many Heliconius butterflies also use their proboscis to feed on pollen; in these species only 20% of the amino acids used in reproduction come from larval feeding, which allow them to develop more quickly as caterpillars, and gives them
3915-437: A water-insoluble, rubbery material which soon sets solid. Butterflies in the genus Agathymus do not fix their eggs to a leaf; instead, the newly laid eggs fall to the base of the plant. Eggs are almost invariably laid on plants. Each species of butterfly has its own host plant range and while some species of butterfly are restricted to just one species of plant, others use a range of plant species, often including members of
4050-422: A week to nearly a year depending on the species. Many species have long larval life stages while others can remain dormant in their pupal or egg stages and thereby survive winters. The Melissa Arctic ( Oeneis melissa ) overwinters twice as a caterpillar. Butterflies may have one or more broods per year. The number of generations per year varies from temperate to tropical regions with tropical regions showing
4185-811: Is a geological epoch that lasted from about 66 to 56 million years ago (mya). It is the first epoch of the Paleogene Period in the modern Cenozoic Era . The name is a combination of the Ancient Greek παλαιός palaiós meaning "old" and the Eocene Epoch (which succeeds the Paleocene), translating to "the old part of the Eocene". The epoch is bracketed by two major events in Earth's history. The K–Pg extinction event , brought on by an asteroid impact ( Chicxulub impact ) and possibly volcanism ( Deccan Traps ), marked
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4320-450: Is above 27 °C (81 °F); when it is cool, they can position themselves to expose the underside of the wings to the sunlight to heat themselves up. If their body temperature reaches 40 °C (104 °F), they can orientate themselves with the folded wings edgewise to the sun. Basking is an activity which is more common in the cooler hours of the morning. Some species have evolved dark wingbases to help in gathering more heat and this
4455-437: Is also evidence this occurred again 300,000 years later in the early Thanetian dubbed MPBE-2. Respectively, about 83 and 132 gigatons of methane-derived carbon were ejected into the atmosphere, which suggests a 2–3 °C (3.6–5.4 °F) rise in temperature, and likely caused heightened seasonality and less stable environmental conditions. It may have also caused an increase of grass in some areas. From 59.7 to 58.1 Ma, during
4590-537: Is controversial, but most likely about 2,500 years. This carbon also interfered with the carbon cycle and caused ocean acidification, and potentially altered and slowed down ocean currents, the latter leading to the expansion of oxygen minimum zones (OMZs) in the deep sea. In surface water, OMZs could have also been caused from the formation of strong thermoclines preventing oxygen inflow, and higher temperatures equated to higher productivity leading to higher oxygen usurpation. Further, expanding OMZs could have caused
4725-458: Is derived from tiny structures called scales, each of which have their own pigments . In Heliconius butterflies, there are three types of scales: yellow/white, black, and red/orange/brown scales. Some mechanism of wing pattern formation are now being solved using genetic techniques. For instance, a gene called cortex determines the colour of scales: deleting cortex turned black and red scales yellow. Mutations, e.g. transposon insertions of
4860-403: Is especially evident in alpine forms. As in many other insects, the lift generated by butterflies is more than can be accounted for by steady-state, non-transitory aerodynamics . Studies using Vanessa atalanta in a wind tunnel show that they use a wide variety of aerodynamic mechanisms to generate force. These include wake capture , vortices at the wing edge, rotational mechanisms and
4995-410: Is extruded and inserted into the female's vagina. A spermatophore is deposited in the female, following which the sperm make their way to a seminal receptacle where they are stored for later use. In both sexes, the genitalia are adorned with various spines, teeth, scales and bristles, which act to prevent the butterfly from mating with an insect of another species. After it emerges from its pupal stage,
5130-451: Is good, especially in some species in the blue/violet range. The antennae are composed of many segments and have clubbed tips (unlike moths that have tapering or feathery antennae). The sensory receptors are concentrated in the tips and can detect odours. Taste receptors are located on the palps and on the feet. The mouthparts are adapted to sucking and the mandibles are usually reduced in size or absent. The first maxillae are elongated into
5265-563: Is native to the Americas, but in the nineteenth century or before, spread across the world, and is now found in Australia, New Zealand, other parts of Oceania, and the Iberian Peninsula . It is not clear how it dispersed; adults may have been blown by the wind or larvae or pupae may have been accidentally transported by humans, but the presence of suitable host plants in their new environment was
5400-435: Is now Castle Rock , Colorado, were calculated to be between 352 and 1,110 parts per million (ppm), with a median of 616 ppm. Based on this and estimated plant-gas exchange rates and global surface temperatures, the climate sensitivity was calculated to be +3 °C when CO 2 levels doubled, compared to 7 °C following the formation of ice at the poles. CO 2 levels alone may have been insufficient in maintaining
5535-548: Is now the Mediterranean Sea tropical. South-central North America had a humid, monsoonal climate along its coastal plain, but conditions were drier to the west and at higher altitudes. Svalbard was temperate, having a mean temperature of 19.2 ± 2.49 °C during its warmest month and 1.7 ± 3.24 °С during its coldest. Global deep water temperatures in the Paleocene likely ranged from 8–12 °C (46–54 °F), compared to 0–3 °C (32–37 °F) in modern day. Based on
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5670-465: Is restricted to the males, and studies have suggested that the nutrients collected may be provided as a nuptial gift , along with the spermatophore, during mating. In hilltopping , males of some species seek hilltops and ridge tops, which they patrol in search for females. Since it usually occurs in species with low population density, it is assumed these landscape points are used as meeting places to find mates. Butterflies use their antennae to sense
5805-692: Is summarized in the below cladogram. Papilionidae [REDACTED] Hedylidae [REDACTED] Hesperiidae [REDACTED] Pieridae [REDACTED] Nymphalidae [REDACTED] Lycaenidae [REDACTED] Riodinidae [REDACTED] Butterfly adults are characterized by their four scale-covered wings, which give the Lepidoptera their name ( Ancient Greek λεπίς lepís, scale + πτερόν pterón, wing). These scales give butterfly wings their colour: they are pigmented with melanins that give them blacks and browns, as well as uric acid derivatives and flavones that give them yellows, but many of
5940-405: Is taken up by the gut, but there may also be large silk glands, and special glands which secrete distasteful or toxic substances. The developing wings are present in later stage instars and the gonads start development in the egg stage. When the larva is fully grown, hormones such as prothoracicotropic hormone (PTTH) are produced. At this point the larva stops feeding, and begins "wandering" in
6075-544: Is why the GSSP was moved to Zumaia. Today, the beginning of the Selandian is marked by the appearances of the nannofossils Fasciculithus tympaniformis , Neochiastozygus perfectus , and Chiasmolithus edentulus , though some foraminifera are used by various authors. The Thanetian was first proposed by Swiss geologist Eugène Renevier , in 1873; he included the south England Thanet , Woolwich , and Reading formations. In 1880, French geologist Gustave Frédéric Dollfus narrowed
6210-777: The Antarctic Peninsula . In the Paleocene, the waterways between the Arctic Ocean and the North Atlantic were somewhat restricted, so North Atlantic Deep Water (NADW) and the Atlantic Meridional Overturning Circulation (AMOC)—which circulates cold water from the Arctic towards the equator—had not yet formed, and so deep water formation probably did not occur in the North Atlantic. The Arctic and Atlantic would not be connected by sufficiently deep waters until
6345-792: The Caribbean Plate ), which had formed from the Galápagos hotspot in the Pacific in the latest Cretaceous, was moving eastward as the North American and South American plates were getting pushed in the opposite direction due to the opening of the Atlantic ( strike-slip tectonics ). This motion would eventually uplift the Isthmus of Panama by 2.6 mya. The Caribbean Plate continued moving until about 50 mya when it reached its current position. The components of
6480-784: The Cretaceous Period and the Mesozoic Era , and initiated the Cenozoic Era and the Paleogene Period. It is divided into three ages : the Danian spanning 66 to 61.6 million years ago (mya), the Selandian spanning 61.6 to 59.2 mya, and the Thanetian spanning 59.2 to 56 mya. It is succeeded by the Eocene. The K–Pg boundary is clearly defined in the fossil record in numerous places around
6615-535: The Holarctic region (comprising most of the Northern Hemisphere) was mainly early members of Ginkgo , Metasequoia , Glyptostrobus , Macginitiea , Platanus , Carya , Ampelopsis , and Cercidiphyllum . Patterns in plant recovery varied significantly with latitude , climate, and altitude. For example, what is now Castle Rock, Colorado featured a rich rainforest only 1.4 million years after
6750-473: The Lycaenidae , form mutual associations with ants. They communicate with the ants using vibrations that are transmitted through the substrate as well as using chemical signals. The ants provide some degree of protection to these larvae and they in turn gather honeydew secretions . Large blue ( Phengaris arion ) caterpillars trick Myrmica ants into taking them back to the ant colony where they feed on
6885-531: The Paleocene–Eocene thermal maximum , a short period of intense warming and ocean acidification brought about by the release of carbon en masse into the atmosphere and ocean systems, which led to a mass extinction of 30–50% of benthic foraminifera –planktonic species which are used as bioindicators of the health of a marine ecosystem—one of the largest in the Cenozoic. This event happened around 55.8 mya, and
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#17328907433037020-771: The Quaternary from the Tertiary in 1829; and Scottish geologist Charles Lyell (ignoring the Quaternary) had divided the Tertiary Epoch into the Eocene , Miocene , Pliocene , and New Pliocene ( Holocene ) Periods in 1833. British geologist John Phillips had proposed the Cenozoic in 1840 in place of the Tertiary, and Austrian paleontologist Moritz Hörnes had introduced the Paleogene for
7155-517: The Transantarctic Mountains . The poles probably had a cool temperate climate; northern Antarctica, Australia, the southern tip of South America, what is now the US and Canada, eastern Siberia, and Europe warm temperate; middle South America, southern and northern Africa, South India, Middle America, and China arid; and northern South America, central Africa, North India, middle Siberia, and what
7290-469: The Weis-Fogh ' clap-and-fling ' mechanism. Butterflies are able to change from one mode to another rapidly. Butterflies are threatened in their early stages by parasitoids and in all stages by predators, diseases and environmental factors. Braconid and other parasitic wasps lay their eggs in lepidopteran eggs or larvae and the wasps' parasitoid larvae devour their hosts, usually pupating inside or outside
7425-452: The ZW sex-determination system where females are the heterogametic sex (ZW) and males homogametic (ZZ). Butterflies are distributed worldwide except Antarctica, totalling some 18,500 species. Of these, 775 are Nearctic ; 7,700 Neotropical ; 1,575 Palearctic ; 3,650 Afrotropical ; and 4,800 are distributed across the combined Oriental and Australian / Oceania regions. The monarch butterfly
7560-600: The non-coding DNA around the cortex gene can turn a black-winged butterfly into a butterfly with a yellow wing band. When the butterfly Bicyclus anynana is subjected to repeated inbreeding in the laboratory, there is a dramatic decrease in egg hatching. This severe inbreeding depression is considered to be likely due to a relatively high mutation rate to recessive alleles with substantial damaging effects and infrequent episodes of inbreeding in nature that might otherwise purge such mutations. Although B. anynana experiences inbreeding depression when forcibly inbred in
7695-801: The opening of the North Atlantic Ocean and seafloor spreading , the divergence of the Greenland Plate from the North American Plate , and, climatically, the PETM by dissociating methane clathrate crystals on the seafloor resulting in the mass release of carbon. North and South America remained separated by the Central American Seaway , though an island arc (the South Central American Arc) had already formed about 73 mya. The Caribbean Large Igneous Province (now
7830-488: The water column . Though the temperature in the latest Danian varied at about the same magnitude, this event coincides with an increase of carbon. About 60.5 mya at the Danian/Selandian boundary, there is evidence of anoxia spreading out into coastal waters, and a drop in sea levels which is most likely explained as an increase in temperature and evaporation, as there was no ice at the poles to lock up water. During
7965-565: The Østerrende Clay . The beginning of this stage was defined by the end of carbonate rock deposition from an open ocean environment in the North Sea region (which had been going on for the previous 40 million years). The Selandian deposits in this area are directly overlain by the Eocene Fur Formation —the Thanetian was not represented here—and this discontinuity in the deposition record
8100-535: The Apollos ( Parnassius ) plugs her genital opening to prevent her from mating again. The vast majority of butterflies have a four-stage life cycle: egg , larva (caterpillar), pupa (chrysalis) and imago (adult). In the genera Colias , Erebia , Euchloe , and Parnassius , a small number of species are known that reproduce semi-parthenogenetically ; when the female dies, a partially developed larva emerges from her abdomen. Butterfly eggs are protected by
8235-521: The Cretaceous, had receded. Between about 60.5 and 54.5 mya, there was heightened volcanic activity in the North Atlantic region—the third largest magmatic event in the last 150 million years—creating the North Atlantic Igneous Province . The proto- Iceland hotspot is sometimes cited as being responsible for the initial volcanism, though rifting and resulting volcanism have also contributed. This volcanism may have contributed to
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#17328907433038370-439: The Cretaceous, tropical or subtropical , and the poles were temperate , with an average global temperature of roughly 24–25 °C (75–77 °F). For comparison, the average global temperature for the period between 1951 and 1980 was 14 °C (57 °F). The latitudinal temperature gradient was approximately 0.24 °C per degree of latitude. The poles also lacked ice caps, though some alpine glaciation did occur in
8505-615: The Eocene and Neogene for the Miocene and Pliocene in 1853. After decades of inconsistent usage, the newly formed International Commission on Stratigraphy (ICS), in 1969, standardized stratigraphy based on the prevailing opinions in Europe: the Cenozoic Era subdivided into the Tertiary and Quaternary sub-eras, and the Tertiary subdivided into the Paleogene and Neogene Periods. In 1978, the Paleogene
8640-470: The Eocene". The Eocene, in turn, is derived from Ancient Greek eo— eos ἠώς meaning "dawn", and—cene kainos καινός meaning "new" or "recent", as the epoch saw the dawn of recent, or modern, life. Paleocene did not come into broad usage until around 1920. In North America and mainland Europe, the standard spelling is "Paleocene", whereas it is "Palaeocene" in the UK. Geologist T. C. R. Pulvertaft has argued that
8775-692: The K–Pg boundary, the largest the Mexican Chicxulub crater whose impact was a major precipitator of the K–Pg extinction, and also the Ukrainian Boltysh crater , dated to 65.4 mya the Canadian Eagle Butte crater (though it may be younger), the Vista Alegre crater (though this may date to about 115 mya ). Silicate glass spherules along the Atlantic coast of the U.S. indicate a meteor impact in
8910-530: The Late Cretaceous became dominant trees in Patagonia, before going extinct. Some plant communities, such as those in eastern North America, were already experiencing an extinction event in the late Maastrichtian, particularly in the 1 million years before the K–Pg extinction event. The "disaster plants" that refilled the emptied landscape crowded out many Cretaceous plants, and resultantly, many went extinct by
9045-520: The Miocene about 24–17 mya. There is evidence that some plants and animals could migrate between India and Asia during the Paleocene, possibly via intermediary island arcs. In the modern thermohaline circulation , warm tropical water becomes colder and saltier at the poles and sinks ( downwelling or deep water formation) that occurs at the North Atlantic near the North Pole and the Southern Ocean near
9180-704: The Northern Component Waters by Greenland in the Eocene—the predecessor of the AMOC—may have caused an intense warming in the North Hemisphere and cooling in the Southern, as well as an increase in deep water temperatures. In the PETM, it is possible deep water formation occurred in saltier tropical waters and moved polewards, which would increase global surface temperatures by warming the poles. Also, Antarctica
9315-412: The Paleocene, especially at the end, in tandem with the increasing global temperature. At the North Pole, woody angiosperms had become the dominant plants, a reversal from the Cretaceous where herbs proliferated. The Iceberg Bay Formation on Ellesmere Island , Nunavut (latitude 75 – 80 ° N) shows remains of a late Paleocene dawn redwood forest, the canopy reaching around 32 m (105 ft), and
9450-473: The Paleocene, with a global average temperature of about 24–25 °C (75–77 °F), compared to 14 °C (57 °F) in more recent times, the Earth had a greenhouse climate without permanent ice sheets at the poles, like the preceding Mesozoic . As such, there were forests worldwide—including at the poles—but they had low species richness in regards to plant life, and were populated by mainly small creatures that were rapidly evolving to take advantage of
9585-413: The South Pole, due to the increasing isolation of Antarctica, many plant taxa were endemic to the continent instead of migrating down. Patagonian flora may have originated in Antarctica. The climate was much cooler than in the Late Cretaceous, though frost probably was not common in at least coastal areas. East Antarctica was likely warm and humid. Because of this, evergreen forests could proliferate as, in
9720-804: The Thanetian is best correlated with the C26r/C26n reversal. Several economically important coal deposits formed during the Paleocene, such as the sub-bituminous Fort Union Formation in the Powder River Basin of Wyoming and Montana, which produces 43% of American coal; the Wilcox Group in Texas, the richest deposits of the Gulf Coastal Plain ; and the Cerrejón mine in Colombia, the largest open-pit mine in
9855-653: The Turgai route connecting Europe with Asia (which were otherwise separated by the Turgai Strait at this time). The Laramide orogeny , which began in the Late Cretaceous, continued to uplift the Rocky Mountains ; it ended at the end of the Paleocene. Because of this and a drop in sea levels resulting from tectonic activity, the Western Interior Seaway , which had divided the continent of North America for much of
9990-430: The abdomen, generally with short prolegs on segments 3–6 and 10; the three pairs of true legs on the thorax have five segments each. Many are well camouflaged; others are aposematic with bright colours and bristly projections containing toxic chemicals obtained from their food plants. The pupa or chrysalis, unlike that of moths, is not wrapped in a cocoon. Many butterflies are sexually dimorphic . Most butterflies have
10125-405: The abdominal segments. These prolegs have rings of tiny hooks called crochets that are engaged hydrostatically and help the caterpillar grip the substrate. The epidermis bears tufts of setae , the position and number of which help in identifying the species. There is also decoration in the form of hairs, wart-like protuberances, horn-like protuberances and spines. Internally, most of the body cavity
10260-438: The absence of frost and a low probability of leaves dying, it was more energy efficient to retain leaves than to regrow them every year. One possibility is that the interior of the continent favored deciduous trees, though prevailing continental climates may have produced winters warm enough to support evergreen forests. As in the Cretaceous, podocarpaceous conifers, Nothofagus , and Proteaceae angiosperms were common. In
10395-502: The adult colour pattern are marked by changes in the expression of particular transcription factors in the early pupa. The reproductive stage of the insect is the winged adult or imago . The surface of both butterflies and moths is covered by scales, each of which is an outgrowth from a single epidermal cell. The head is small and dominated by the two large compound eyes . These are capable of distinguishing flower shapes or motion but cannot view distant objects clearly. Colour perception
10530-467: The air for wind and scents. The antennae come in various shapes and colours; the hesperiids have a pointed angle or hook to the antennae, while most other families show knobbed antennae. The antennae are richly covered with sensory organs known as sensillae . A butterfly's sense of taste is coordinated by chemoreceptors on the tarsi , or feet, which work only on contact, and are used to determine whether an egg-laying insect's offspring will be able to feed on
10665-470: The algae Discoaster and a diversification of Heliolithus , though the best correlation is in terms of paleomagnetism . A chron is the occurrence of a geomagnetic reversal —when the North and South poles switch polarities . Chron 1 (C1n) is defined as modern day to about 780,000 years ago, and the n denotes "normal" as in the polarity of today, and an r "reverse" for the opposite polarity. The beginning of
10800-434: The ant eggs and larvae in a parasitic relationship. Caterpillars mature through a series of developmental stages known as instars . Near the end of each stage, the larva undergoes a process called apolysis , mediated by the release of a series of neurohormones . During this phase, the cuticle , a tough outer layer made of a mixture of chitin and specialized proteins , is released from the softer epidermis beneath, and
10935-507: The atmosphere. For the following half million years, the carbon isotope gradient—a difference in the C / C ratio between surface and deep ocean water, causing carbon to cycle into the deep sea—may have shut down. This, termed a "Strangelove ocean", indicates low oceanic productivity ; resultant decreased phytoplankton activity may have led to a reduction in cloud seeds and, thus, marine cloud brightening , causing global temperatures to increase by 6 °C ( CLAW hypothesis ). Following
11070-473: The beginning of the Paleocene and killed off 75% of species, most famously the non-avian dinosaurs. The end of the epoch was marked by the Paleocene–Eocene Thermal Maximum (PETM), which was a major climatic event wherein about 2,500–4,500 gigatons of carbon were released into the atmosphere and ocean systems, causing a spike in global temperatures and ocean acidification . In the Paleocene,
11205-658: The blues, greens, reds and iridescent colours are created by structural coloration produced by the micro-structures of the scales and hairs. As in all insects, the body is divided into three sections: the head, thorax , and abdomen . The thorax is composed of three segments, each with a pair of legs. In most families of butterfly the antennae are clubbed, unlike those of moths which may be threadlike or feathery. The long proboscis can be coiled when not in use for sipping nectar from flowers. Nearly all butterflies are diurnal , have relatively bright colours, and hold their wings vertically above their bodies when at rest, unlike
11340-585: The boundary; for example, in the Williston Basin of North Dakota, an estimated 1/3 to 3/5 of plant species went extinct. The K–Pg extinction event ushered in a floral turnover; for example, the once commonplace Araucariaceae conifers were almost fully replaced by Podocarpaceae conifers, and the Cheirolepidiaceae , a group of conifers that had dominated during most of the Mesozoic but had become rare during
11475-539: The continents of the Northern Hemisphere were still connected via some land bridges ; and South America, Antarctica, and Australia had not completely separated yet. The Rocky Mountains were being uplifted, the Americas had not yet joined, the Indian Plate had begun its collision with Asia, and the North Atlantic Igneous Province was forming in the third-largest magmatic event of the last 150 million years. In
11610-731: The country. Paleocene coal has been mined extensively in Svalbard , Norway, since near the beginning of the 20th century, and late Paleocene and early Eocene coal is widely distributed across the Canadian Arctic Archipelago and northern Siberia. In the North Sea, Paleocene-derived natural gas reserves, when they were discovered, totaled approximately 2.23 trillion m (7.89 trillion ft ), and oil in place 13.54 billion barrels. Important phosphate deposits—predominantly of francolite —near Métlaoui , Tunisia were formed from
11745-404: The dark forest floor, and epiphytism where a plant grows on another plant in response to less space on the forest floor. Despite increasing density—which could act as fuel—wildfires decreased in frequency from the Cretaceous to the early Eocene as the atmospheric oxygen levels decreased to modern day levels, though they may have been more intense. There was a major die-off of plant species over
11880-464: The definition to just the Thanet Formation. The Thanetian begins a little after the mid-Paleocene biotic event —a short-lived climatic event caused by an increase in methane —recorded at Itzurun as a dark 1 m (3.3 ft) interval from a reduction of calcium carbonate . At Itzurun, it begins about 29 m (95 ft) above the base of the Selandian, and is marked by the first appearance of
12015-441: The desiccated husk. Most wasps are very specific about their host species and some have been used as biological controls of pest butterflies like the large white butterfly . When the small cabbage white was accidentally introduced to New Zealand, it had no natural enemies. In order to control it, some pupae that had been parasitised by a chalcid wasp were imported, and natural control was thus regained. Some flies lay their eggs on
12150-529: The early to middle Eocene. There is evidence of deep water formation in the North Pacific to at least a depth of about 2,900 m (9,500 ft). The elevated global deep water temperatures in the Paleocene may have been too warm for thermohaline circulation to be predominately heat driven. It is possible that the greenhouse climate shifted precipitation patterns, such that the Southern Hemisphere
12285-529: The ecosystem may have been disrupted by only a small change in climate. The warm Paleocene climate, much like that of the Cretaceous , allowed for diverse polar forests. Whereas precipitation is a major factor in plant diversity nearer the equator, polar plants had to adapt to varying light availability ( polar nights and midnight suns ) and temperatures. Because of this, plants from both poles independently evolved some similar characteristics, such as broad leaves. Plant diversity at both poles increased throughout
12420-419: The epidermis begins to form a new cuticle. At the end of each instar, the larva moults , the old cuticle splits and the new cuticle expands, rapidly hardening and developing pigment. Development of butterfly wing patterns begins by the last larval instar. Caterpillars have short antennae and several simple eyes . The mouthparts are adapted for chewing with powerful mandibles and a pair of maxillae, each with
12555-474: The event, probably due to a rain shadow effect causing regular monsoon seasons. Conversely, low plant diversity and a lack of specialization in insects in the Colombian Cerrejón Formation , dated to 58 mya, indicates the ecosystem was still recovering from the K–Pg extinction event 7 million years later. Flowering plants ( angiosperms ), which had become dominant among forest taxa by
12690-535: The extreme disruptions in the aftermath of the K-Pg extinction event, the relatively cool, though still greenhouse, conditions of the Late Cretaceous–Early Palaeogene Cool Interval (LKEPCI) that began in the Late Cretaceous continued. The Dan –C2 Event 65.2 mya in the early Danian spanned about 100,000 years, and was characterized by an increase in carbon, particularly in the deep sea. Since
12825-659: The family Hesperiidae (skippers). Molecular clock estimates suggest that butterflies originated sometime in the Late Cretaceous , but only significantly diversified during the Cenozoic, with one study suggesting a North American origin for the group. The oldest American butterfly is the Late Eocene Prodryas persephone from the Florissant Fossil Beds , approximately 34 million years old. Butterflies are divided into seven families that contain
12960-403: The food plant on which their larvae , known as caterpillars , will feed. The caterpillars grow, sometimes very rapidly, and when fully developed, pupate in a chrysalis . When metamorphosis is complete, the pupal skin splits, the adult insect climbs out, expands its wings to dry, and flies off. Some butterflies, especially in the tropics, have several generations in a year, while others have
13095-525: The former southern supercontinent Gondwanaland in the Southern Hemisphere continued to drift apart, but Antarctica was still connected to South America and Australia. Africa was heading north towards Europe, and the Indian subcontinent towards Asia, which would eventually close the Tethys Ocean . The Indian and Eurasian Plates began colliding in the Paleocene, with uplift (and a land connection) beginning in
13230-409: The friction of their overlapping parts. The front two segments have a pair of spiracles which are used in respiration. The abdomen consists of ten segments and contains the gut and genital organs. The front eight segments have spiracles and the terminal segment is modified for reproduction. The male has a pair of clasping organs attached to a ring structure, and during copulation, a tubular structure
13365-544: The grass was growing. The earliest Lepidoptera fossils date to the Triassic - Jurassic boundary, around 200 million years ago. Butterflies evolved from moths, so while the butterflies are monophyletic (forming a single clade ), the moths are not. The oldest known butterfly is Protocoeliades kristenseni from the Palaeocene aged Fur Formation of Denmark, approximately 55 million years old, which belongs to
13500-453: The greenhouse climate, and some positive feedbacks must have been active, such as some combination of cloud, aerosol, or vegetation related processes. A 2019 study identified changes in orbital eccentricity as the dominant drivers of climate between the late Cretaceous and the early Eocene. The effects of the meteor impact and volcanism 66 mya and the climate across the K–Pg boundary were likely fleeting, and climate reverted to normal in
13635-1030: The laboratory it recovers within a few generation when allowed to breed freely. During mate selection, adult females do not innately avoid or learn to avoid siblings, implying that such detection may not be critical to reproductive fitness. Inbreeding may persist in B anynana because the probability of encountering close relatives is rare in nature; that is, movement ecology may mask the deleterious effect of inbreeding resulting in relaxation of selection for active inbreeding avoidance behaviors. Butterflies feed primarily on nectar from flowers. Some also derive nourishment from pollen , tree sap, rotting fruit, dung, decaying flesh, and dissolved minerals in wet sand or dirt. Butterflies are important as pollinators for some species of plants. In general, they do not carry as much pollen load as bees , but they are capable of moving pollen over greater distances. Flower constancy has been observed for at least one species of butterfly. Adult butterflies consume only liquids, ingested through
13770-473: The late Danian, there was a warming event and evidence of ocean acidification associated with an increase in carbon; at this time, there was major seafloor spreading in the Atlantic and volcanic activity along the southeast margin of Greenland. The Latest Danian Event, also known as the Top Chron C27n Event, lasted about 200,000 years and resulted in a 1.6–2.8 °C increase in temperatures throughout
13905-825: The late Paleocene to the early Eocene. Impact craters formed in the Paleocene include: the Connolly Basin crater in Western Australia less than 60 mya, the Texan Marquez crater 58 mya, the Greenlandic Hiawatha Glacier crater 58 mya, and possibly the Jordan Jabel Waqf as Suwwan crater which dates to between 56 and 37 mya. Vanadium -rich osbornite from the Isle of Skye , Scotland, dating to 60 mya may be impact ejecta . Craters were also formed near
14040-491: The late Selandian and early Thanetian, organic carbon burial resulted in a period of climatic cooling, sea level fall and transient ice growth. This interval saw the highest δ O values of the epoch. The Paleocene–Eocene Thermal Maximum was an approximately 200,000-year-long event where the global average temperature rose by some 5 to 8 °C (9 to 14 °F), and mid-latitude and polar areas may have exceeded modern tropical temperatures of 24–29 °C (75–84 °F). This
14175-478: The latter spelling is incorrect because this would imply either a translation of "old recent" or a derivation from "pala" and "Eocene", which would be incorrect because the prefix palæo- uses the ligature æ instead of "a" and "e" individually, so only both characters or neither should be dropped, not just one. The Paleocene Epoch is the 10 million year time interval directly after the K–Pg extinction event , which ended
14310-506: The majority of moths which fly by night, are often cryptically coloured (well camouflaged), and either hold their wings flat (touching the surface on which the moth is standing) or fold them closely over their bodies. Some day-flying moths, such as the hummingbird hawk-moth , are exceptions to these rules. Butterfly larvae , caterpillars , have a hard ( sclerotised ) head with strong mandibles used for cutting their food, most often leaves. They have cylindrical bodies, with ten segments to
14445-558: The mid- Maastrichtian , more and more carbon had been sequestered in the deep sea possibly due to a global cooling trend and increased circulation into the deep sea. The Dan–C2 event may represent a release of this carbon after deep sea temperatures rose to a certain threshold, as warmer water can dissolve less carbon. Alternatively, the cause of the Dan-C2 event may have been a pulse of Deccan Traps volcanism. Savanna may have temporarily displaced forestland in this interval. Around 62.2 mya in
14580-553: The mid-Palaeocene biotic event (MPBE), also known as the Early Late Palaeocene Event (ELPE), around 59 Ma (roughly 50,000 years before the Selandian/Thanetian boundary), the temperature spiked probably due to a mass release of the deep sea methane hydrate into the atmosphere and ocean systems. Carbon was probably output for 10–11,000 years, and the aftereffects likely subsided around 52–53,000 years later. There
14715-399: The middle Cretaceous 110–90 mya, continued to develop and proliferate, more so to take advantage of the recently emptied niches and an increase in rainfall. Along with them coevolved the insects that fed on these plants and pollinated them. Predation by insects was especially high during the PETM. Many fruit-bearing plants appeared in the Paleocene in particular, probably to take advantage of
14850-432: The middle Paleocene. The strata immediately overlaying the K–Pg extinction event are especially rich in fern fossils. Ferns are often the first species to colonize areas damaged by forest fires , so this " fern spike " may mark the recovery of the biosphere following the impact (which caused blazing fires worldwide). The diversifying herb flora of the early Paleocene either represent pioneer species which re-colonized
14985-401: The name is ancient, but modern Dutch and German use different words ( vlinder and Schmetterling ) and the common name often varies substantially between otherwise closely related languages. A possible source of the name is the bright yellow male of the brimstone ( Gonepteryx rhamni ); another is that butterflies were on the wing in meadows during the spring and summer butter season while
15120-598: The newly evolving birds and mammals for seed dispersal . In what is now the Gulf Coast , angiosperm diversity increased slowly in the early Paleocene, and more rapidly in the middle and late Paleocene. This may have been because the effects of the K–Pg extinction event were still to some extent felt in the early Paleocene, the early Paleocene may not have had as many open niches, early angiosperms may not have been able to evolve at such an accelerated rate as later angiosperms, low diversity equates to lower evolution rates, or there
15255-411: The oceans, the thermohaline circulation probably was much different from what it is today, with downwellings occurring in the North Pacific rather than the North Atlantic, and water density mainly being controlled by salinity rather than temperature. The K–Pg extinction event caused a floral and faunal turnover of species, with previously abundant species being replaced by previously uncommon ones. In
15390-434: The original areas the stages were defined, accessibility, and the protected status of the area due to its geological significance. The Selandian was first proposed by Danish geologist Alfred Rosenkrantz in 1924 based on a section of fossil-rich glauconitic marls overlain by gray clay which unconformably overlies Danian chalk and limestone . The area is now subdivided into the Æbelø Formation , Holmehus Formation , and
15525-408: The outside of caterpillars and the newly hatched fly larvae bore their way through the skin and feed in a similar way to the parasitoid wasp larvae. Predators of butterflies include ants, spiders, wasps, and birds. Palaeocene The Paleocene ( IPA : / ˈ p æ l i . ə s iː n , - i . oʊ -, ˈ p eɪ l i -/ PAL -ee-ə-seen, -ee-oh-, PAY -lee- ), or Palaeocene ,
15660-529: The proboscis. They sip water from damp patches for hydration and feed on nectar from flowers, from which they obtain sugars for energy, and sodium and other minerals vital for reproduction. Several species of butterflies need more sodium than that provided by nectar and are attracted by sodium in salt; they sometimes land on people, attracted by the salt in human sweat. Some butterflies also visit dung and scavenge rotting fruit or carcasses to obtain minerals and nutrients. In many species, this mud-puddling behaviour
15795-444: The proliferation of sulfate-reducing microorganisms which create highly toxic hydrogen sulfide H 2 S as a waste product. During the event, the volume of sulfidic water may have been 10–20% of total ocean volume, in comparison to today's 1%. This may have also caused chemocline upwellings along continents and the dispersal of H 2 S into the atmosphere. During the PETM there was a temporary dwarfing of mammals apparently caused by
15930-601: The proposal was officially published in 2006. The Selandian and Thanetian are both defined in Itzurun beach by the Basque town of Zumaia , 43°18′02″N 2°15′34″W / 43.3006°N 2.2594°W / 43.3006; -2.2594 , as the area is a continuous early Santonian to early Eocene sea cliff outcrop . The Paleocene section is an essentially complete, exposed record 165 m (541 ft) thick, mainly composed of alternating hemipelagic sediments deposited at
16065-431: The quest for a suitable pupation site, often the underside of a leaf or other concealed location. There it spins a button of silk which it uses to fasten its body to the surface and moults for a final time. While some caterpillars spin a cocoon to protect the pupa, most species do not. The naked pupa, often known as a chrysalis, usually hangs head down from the cremaster, a spiny pad at the posterior end, but in some species
16200-461: The recently emptied Earth. Though some animals attained great size, most remained rather small. The forests grew quite dense in the general absence of large herbivores. Mammals proliferated in the Paleocene, and the earliest placental and marsupial mammals are recorded from this time, but most Paleocene taxa have ambiguous affinities . In the seas, ray-finned fish rose to dominate open ocean and recovering reef ecosystems. The word "Paleocene"
16335-404: The recently emptied landscape, or a response to the increased amount of shade provided in a forested landscape. Lycopods , ferns, and angiosperm shrubs may have been important components of the Paleocene understory . In general, the forests of the Paleocene were species-poor, and diversity did not fully recover until the end of the Paleocene. For example, the floral diversity of what is now
16470-656: The region at the PETM. During the Paleocene, the continents continued to drift toward their present positions. In the Northern Hemisphere, the former components of Laurasia (North America and Eurasia) were, at times, connected via land bridges: Beringia (at 65.5 and 58 mya) between North America and East Asia, the De Geer route (from 71 to 63 mya) between Greenland and Scandinavia , the Thulean route (at 57 and 55.8 mya) between North America and Western Europe via Greenland, and
16605-798: The same is true in the North Dakotan Almont/Beicegel Creek —such as Ochnaceae , Cyclocarya , and Ginkgo cranei —indicating the same floral families have characterized South American rainforests and the American Western Interior since the Paleocene. The extinction of large herbivorous dinosaurs may have allowed the forests to grow quite dense, and there is little evidence of wide open plains. Plants evolved several techniques to cope with high plant density, such as buttressing to better absorb nutrients and compete with other plants, increased height to reach sunlight, larger diaspore in seeds to provide added nutrition on
16740-463: The upper limit, average sea surface temperatures (SSTs) at 60° N and S would have been the same as deep sea temperatures, at 30° N and S about 23 °C (73 °F), and at the equator about 28 °C (82 °F). In the Danish Palaeocene sea, SSTs were cooler than those of the preceding Late Cretaceous and the succeeding Eocene. The Paleocene foraminifera assemblage globally indicates
16875-498: The upward excursion in temperature. The warm, wet climate supported tropical and subtropical forests worldwide, mainly populated by conifers and broad-leafed trees. In Patagonia, the landscape supported tropical rainforests , cloud rainforests , mangrove forests , swamp forests , savannas , and sclerophyllous forests. In the Colombian Cerrejón Formation , fossil flora belong to the same families as modern day flora—such as palm trees , legumes , aroids , and malvales —and
17010-579: The world by a high- iridium band, as well as discontinuities with fossil flora and fauna. It is generally thought that a 10 to 15 km (6 to 9 mi) wide asteroid impact, forming the Chicxulub Crater in the Yucatán Peninsula in the Gulf of Mexico , and Deccan Trap volcanism caused a cataclysmic event at the boundary resulting in the extinction of 75% of all species. The Paleocene ended with
17145-455: Was due to an ejection of 2,500–4,500 gigatons of carbon into the atmosphere, most commonly explained as the perturbation and release of methane clathrate deposits in the North Atlantic from tectonic activity and resultant increase in bottom water temperatures. Other proposed hypotheses include methane release from the heating of organic matter at the seafloor rather than methane clathrates, or melting permafrost . The duration of carbon output
17280-458: Was first used by French paleobotanist and geologist Wilhelm Philipp Schimper in 1874 while describing deposits near Paris (spelled "Paléocène" in his treatise). By this time, Italian geologist Giovanni Arduino had divided the history of life on Earth into the Primary ( Paleozoic ), Secondary ( Mesozoic ), and Tertiary in 1759; French geologist Jules Desnoyers had proposed splitting off
17415-577: Was not a major contributor to the greenhouse climate, and deep water temperatures more likely change as a response to global temperature change rather than affecting it. In the Arctic, coastal upwelling may have been largely temperature and wind-driven. In summer, the land surface temperature was probably higher than oceanic temperature, and the opposite was true in the winter, which is consistent with monsoon seasons in Asia. Open-ocean upwelling may have also been possible. The Paleocene climate was, much like in
17550-429: Was not much angiosperm migration into the region in the early Paleocene. Over the K–Pg extinction event, angiosperms had a higher extinction rate than gymnosperms (which include conifers, cycads , and relatives) and pteridophytes (ferns, horsetails , and relatives); zoophilous angiosperms (those that relied on animals for pollination) had a higher rate than anemophilous angiosperms; and evergreen angiosperms had
17685-546: Was officially defined as the Paleocene, Eocene, and Oligocene Epochs; and the Neogene as the Miocene and Pliocene Epochs. In 1989, Tertiary and Quaternary were removed from the time scale due to the arbitrary nature of their boundary, but Quaternary was reinstated in 2009. The term "Paleocene" is a portmanteau combination of the Ancient Greek palaios παλαιός meaning "old", and the word "Eocene", and so means "the old part of
17820-439: Was one of the most significant periods of global change during the Cenozoic. Geologists divide the rocks of the Paleocene into a stratigraphic set of smaller rock units called stages , each formed during corresponding time intervals called ages. Stages can be defined globally or regionally. For global stratigraphic correlation, the ICS ratify global stages based on a Global Boundary Stratotype Section and Point (GSSP) from
17955-527: Was shown that the Danian and the Montian are the same, the ICS decided to define the Danian as starting with the K–Pg boundary, thus ending the practice of including the Danian in the Cretaceous. In 1991, the GSSP was defined as a well-preserved section in the El Haria Formation near El Kef , Tunisia, 36°09′13″N 8°38′55″E / 36.1537°N 8.6486°E / 36.1537; 8.6486 , and
18090-496: Was still connected to South America and Australia, and, because of this, the Antarctic Circumpolar Current —which traps cold water around the continent and prevents warm equatorial water from entering—had not yet formed. Its formation may have been related in the freezing of the continent. Warm coastal upwellings at the poles would have inhibited permanent ice cover. Conversely, it is possible deep water circulation
18225-544: Was wetter than the Northern, or the Southern experienced less evaporation than the Northern. In either case, this would have made the Northern more saline than the Southern, creating a density difference and a downwelling in the North Pacific traveling southward. Deep water formation may have also occurred in the South Atlantic. It is largely unknown how global currents could have affected global temperature. The formation of
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