The Jurassic period was a geologic period and system that spanned 56 million years from the end of the Triassic Period 201.3 million years ago to the beginning of the Cretaceous Period 145 Mya. The Jurassic constitutes the middle period of the Mesozoic Era known as the Age of Reptiles; the start of the period was marked by the major Triassic–Jurassic extinction event. Two other extinction events occurred during the period: the Pliensbachian-Toarcian extinction in the Early Jurassic, the Tithonian event at the end; the Jurassic period is divided into three epochs: Early and Late. In stratigraphy, the Jurassic is divided into the Lower Jurassic, Middle Jurassic, Upper Jurassic series of rock formations; the Jurassic is named after the Jura Mountains within the European Alps, where limestone strata from the period were first identified. By the beginning of the Jurassic, the supercontinent Pangaea had begun rifting into two landmasses: Laurasia to the north, Gondwana to the south; this created more coastlines and shifted the continental climate from dry to humid, many of the arid deserts of the Triassic were replaced by lush rainforests.
On land, the fauna transitioned from the Triassic fauna, dominated by both dinosauromorph and crocodylomorph archosaurs, to one dominated by dinosaurs alone. The first birds appeared during the Jurassic, having evolved from a branch of theropod dinosaurs. Other major events include the appearance of the earliest lizards, the evolution of therian mammals, including primitive placentals. Crocodilians made the transition from a terrestrial to an aquatic mode of life; the oceans were inhabited by marine reptiles such as ichthyosaurs and plesiosaurs, while pterosaurs were the dominant flying vertebrates. The chronostratigraphic term "Jurassic" is directly linked to the Jura Mountains, a mountain range following the course of the France–Switzerland border. During a tour of the region in 1795, Alexander von Humboldt recognized the limestone dominated mountain range of the Jura Mountains as a separate formation that had not been included in the established stratigraphic system defined by Abraham Gottlob Werner, he named it "Jura-Kalkstein" in 1799.
The name "Jura" is derived from the Celtic root *jor via Gaulish *iuris "wooded mountain", borrowed into Latin as a place name, evolved into Juria and Jura. The Jurassic period is divided into three epochs: Early and Late. In stratigraphy, the Jurassic is divided into the Lower Jurassic, Middle Jurassic, Upper Jurassic series of rock formations known as Lias and Malm in Europe; the separation of the term Jurassic into three sections originated with Leopold von Buch. The faunal stages from youngest to oldest are: During the early Jurassic period, the supercontinent Pangaea broke up into the northern supercontinent Laurasia and the southern supercontinent Gondwana; the Jurassic North Atlantic Ocean was narrow, while the South Atlantic did not open until the following Cretaceous period, when Gondwana itself rifted apart. The Tethys Sea closed, the Neotethys basin appeared. Climates were warm, with no evidence of a glacier having appeared; as in the Triassic, there was no land over either pole, no extensive ice caps existed.
The Jurassic geological record is good in western Europe, where extensive marine sequences indicate a time when much of that future landmass was submerged under shallow tropical seas. In contrast, the North American Jurassic record is the poorest of the Mesozoic, with few outcrops at the surface. Though the epicontinental Sundance Sea left marine deposits in parts of the northern plains of the United States and Canada during the late Jurassic, most exposed sediments from this period are continental, such as the alluvial deposits of the Morrison Formation; the Jurassic was a time of calcite sea geochemistry in which low-magnesium calcite was the primary inorganic marine precipitate of calcium carbonate. Carbonate hardgrounds were thus common, along with calcitic ooids, calcitic cements, invertebrate faunas with dominantly calcitic skeletons; the first of several massive batholiths were emplaced in the northern American cordillera beginning in the mid-Jurassic, marking the Nevadan orogeny. Important Jurassic exposures are found in Russia, South America, Japan and the United Kingdom.
In Africa, Early Jurassic strata are distributed in a similar fashion to Late Triassic beds, with more common outcrops in the south and less common fossil beds which are predominated by tracks to the north. As the Jurassic proceeded and more iconic groups of dinosaurs like sauropods and ornithopods proliferated in Africa. Middle Jurassic strata are neither well studied in Africa. Late Jurassic strata are poorly represented apart from the spectacular Tendaguru fauna in Tanzania; the Late Jurassic life of Tendaguru is similar to that found in western North America's Morrison Formation. During the Jurassic period, the primary vertebrates living in the sea were marine reptiles; the latter include ichthyosaurs, which were at the peak of their diversity, plesiosaurs and marine crocodiles of the families Teleosauridae and Metriorhynchidae. Numerous turtles could be found in rivers. In the invertebrate world, several new groups appeared, including rudists (a reef-formi
The Ordovician is a geologic period and system, the second of six periods of the Paleozoic Era. The Ordovician spans 41.2 million years from the end of the Cambrian Period 485.4 million years ago to the start of the Silurian Period 443.8 Mya. The Ordovician, named after the Celtic tribe of the Ordovices, was defined by Charles Lapworth in 1879 to resolve a dispute between followers of Adam Sedgwick and Roderick Murchison, who were placing the same rock beds in northern Wales into the Cambrian and Silurian systems, respectively. Lapworth recognized that the fossil fauna in the disputed strata were different from those of either the Cambrian or the Silurian systems, placed them in a system of their own; the Ordovician received international approval in 1960, when it was adopted as an official period of the Paleozoic Era by the International Geological Congress. Life continued to flourish during the Ordovician as it did in the earlier Cambrian period, although the end of the period was marked by the Ordovician–Silurian extinction events.
Invertebrates, namely molluscs and arthropods, dominated the oceans. The Great Ordovician Biodiversification Event increased the diversity of life. Fish, the world's first true vertebrates, continued to evolve, those with jaws may have first appeared late in the period. Life had yet to diversify on land. About 100 times as many meteorites struck the Earth per year during the Ordovician compared with today; the Ordovician Period began with a major extinction called the Cambrian–Ordovician extinction event, about 485.4 Mya. It lasted for about 42 million years and ended with the Ordovician–Silurian extinction events, about 443.8 Mya which wiped out 60% of marine genera. The dates given are recent radiometric dates and vary from those found in other sources; this second period of the Paleozoic era created abundant fossils that became major petroleum and gas reservoirs. The boundary chosen for the beginning of both the Ordovician Period and the Tremadocian stage is significant, it correlates well with the occurrence of widespread graptolite and trilobite species.
The base of the Tremadocian allows scientists to relate these species not only to each other, but to species that occur with them in other areas. This makes it easier to place many more species in time relative to the beginning of the Ordovician Period. A number of regional terms have been used to subdivide the Ordovician Period. In 2008, the ICS erected a formal international system of subdivisions. There exist Baltoscandic, Siberian, North American, Chinese Mediterranean and North-Gondwanan regional stratigraphic schemes; the Ordovician Period in Britain was traditionally broken into Early and Late epochs. The corresponding rocks of the Ordovician System are referred to as coming from the Lower, Middle, or Upper part of the column; the faunal stages from youngest to oldest are: Late Ordovician Hirnantian/Gamach Rawtheyan/Richmond Cautleyan/Richmond Pusgillian/Maysville/Richmond Middle Ordovician Trenton Onnian/Maysville/Eden Actonian/Eden Marshbrookian/Sherman Longvillian/Sherman Soudleyan/Kirkfield Harnagian/Rockland Costonian/Black River Chazy Llandeilo Whiterock Llanvirn Early Ordovician Cassinian Arenig/Jefferson/Castleman Tremadoc/Deming/Gaconadian The Tremadoc corresponds to the Tremadocian.
The Floian corresponds to the lower Arenig. The Llanvirn occupies the rest of the Darriwilian, terminates with it at the base of the Late Ordovician; the Sandbian represents the first half of the Caradoc. During the Ordovician, the southern continents were collected into Gondwana. Gondwana started the period in equatorial latitudes and, as the period progressed, drifted toward the South Pole. Early in the Ordovician, the continents of Laurentia and Baltica were still independent continents, but Baltica began to move towards Laurentia in the period, causing the Iapetus Ocean between them to shrink; the small continent Avalonia separated from Gondwana and began to move north towards Baltica and Laurentia, opening the Rheic Ocean between Gondwana and Avalonia. The Taconic orogeny, a major mountain-building episode, was well under way in Cambrian times. In the early and middle Ordovician, temperatures were mild, but at the beginning of the Late Ordovician, from 460 to 450 Ma, volcanoes along the margin of the Iapetus Ocean spewed massive amounts of carbon dioxide, a greenhouse gas, into the atmosphere, turning the planet into a hothouse.
Sea levels were high, but as Gondwana moved south, ice accumulated into glaciers and sea levels dropped. At first, low-lying sea beds increased diversity, but glaciation led to mass extinctions as the seas drained and continental shelves became dry land. During the Ordovician, in fact during the Tremadocian, marine transgressions worldwide were the greatest for which evidence is preserved; these volcanic island arcs collided with proto North America to form the Appalachian mountains. By the end of the Late Ordovician the volcanic emissions had stopped. Gondwana had by that time neared the South Pole and was glaciated
Bats are mammals of the order Chiroptera. Bats are more manoeuvrable than birds, flying with their long spread-out digits covered with a thin membrane or patagium; the smallest bat, arguably the smallest extant mammal, is Kitti's hog-nosed bat, 29–34 mm in length, 15 cm across the wings and 2–2.6 g in mass. The largest bats are the flying foxes and the giant golden-crowned flying fox, Acerodon jubatus, which can weigh 1.6 kg and have a wingspan of 1.7 m. The second largest order of mammals, bats comprise about 20% of all classified mammal species worldwide, with over 1,200 species; these were traditionally divided into two suborders: the fruit-eating megabats, the echolocating microbats. But more recent evidence has supported dividing the order into Yinpterochiroptera and Yangochiroptera, with megabats as members of the former along with several species of microbats. Many bats are insectivores, most of the rest are frugivores. A few species feed on animals other than insects. Most bats are nocturnal, many roost in caves or other refuges.
Bats are present throughout the world, with the exception of cold regions. They are important in their ecosystems for dispersing seeds. Bats provide humans at the cost of some threats. Bat dung has been used as fertiliser. Bats consume insect pests, they are sometimes numerous enough to serve as tourist attractions, are used as food across Asia and the Pacific Rim. They are natural reservoirs such as rabies. In many cultures, bats are popularly associated with darkness, witchcraft and death. An older English name for bats is flittermouse, which matches their name in other Germanic languages, related to the fluttering of wings. Middle English had bakke, most cognate with Old Swedish natbakka, which may have undergone a shift from -k- to -t- influenced by Latin blatta, "moth, nocturnal insect"; the word "bat" was first used in the early 1570s. The name "Chiroptera" derives from Ancient Greek: χείρ – cheir, "hand" and πτερόν – pteron, "wing"; the delicate skeletons of bats do not fossilise well, it is estimated that only 12% of bat genera that lived have been found in the fossil record.
Most of the oldest known bat fossils were very similar to modern microbats, such as Archaeopteropus. The extinct bats Palaeochiropteryx tupaiodon and Hassianycteris kumari are the first fossil mammals whose colouration has been discovered: both were reddish-brown. Bats were grouped in the superorder Archonta, along with the treeshrews and primates. Modern genetic evidence now places bats in the superorder Laurasiatheria, with its sister taxon as Fereuungulata, which includes carnivorans, odd-toed ungulates, even-toed ungulates, cetaceans. One study places Chiroptera as a sister taxon to odd-toed ungulates; the phylogenetic relationships of the different groups of bats have been the subject of much debate. The traditional subdivision into Megachiroptera and Microchiroptera reflected the view that these groups of bats had evolved independently of each other for a long time, from a common ancestor capable of flight; this hypothesis recognised differences between microbats and megabats and acknowledged that flight has only evolved once in mammals.
Most molecular biological evidence supports the view that bats form a monophyletic group. Genetic evidence indicates that megabats originated during the early Eocene, belong within the four major lines of microbats. Two new suborders have been proposed. Yangochiroptera includes the other families of a conclusion supported by a 2005 DNA study. A 2013 phylogenomic study supported the two new proposed suborders. In the 1980s, a hypothesis based on morphological evidence stated the Megachiroptera evolved flight separately from the Microchiroptera; the flying primate hypothesis proposed that, when adaptations to flight are removed, the Megachiroptera are allied to primates by anatomical features not shared with Microchiroptera. For example, the brains of megabats have advanced characteristics. Although recent genetic studies support the monophyly of bats, debate continues about the meaning of the genetic and morphological evidence; the 2003 discovery of an early fossil bat from the 52 million year old Green River Formation, Onychonycteris finneyi, indicates that flight evolved before echolocative abilities.
Onychonycteris had claws on all five of its fingers, whereas modern bats have at most two claws on two digits of each hand. It had longer hind legs and shorter forearms, similar to climbing mammals that hang under branches, such as sloths and gibbons; this palm-sized bat had short, broad wings, suggesting that it could not fly as fast or as far as bat species. Instead of flapping its wings continuously while flying, Onychonycteris alternated between flaps and
Flying and gliding animals
A number of animals have evolved aerial locomotion, either by powered flight or by gliding. Flying and gliding animals have evolved separately many times, without any single ancestor. Flight has evolved at least four times, in the insects, pterosaurs and bats. Gliding has evolved on many more occasions; the development is to aid canopy animals in getting from tree to tree, although there are other possibilities. Gliding, in particular, has evolved among rainforest animals in the rainforests in Asia where the trees are tall and spaced. Several species of aquatic animals, a few amphibians and reptiles have evolved to acquire this gliding flight ability as a means of evading predators. Animal aerial locomotion can be divided into two categories -- unpowered. In unpowered modes of locomotion, the animal uses aerodynamics forces exerted on the body due to wind or falling through the air. In powered flight, the animal uses muscular power to generate aerodynamic forces. Animals using unpowered aerial locomotion cannot maintain altitude and speed due to unopposed drag, while animals using powered flight can maintain steady, level flight as long as their muscles are capable of doing so.
These modes of locomotion require an animal start from a raised location, converting that potential energy into kinetic energy and using aerodynamic forces to control trajectory and angle of descent. Energy is continually lost to drag without being replaced, thus these methods of locomotion have limited range and duration. Falling: decreasing altitude under the force of gravity, using no adaptations to increase drag or provide lift. Parachuting: falling at an angle greater than 45° from the horizontal with adaptations to increase drag forces. Small animals may be carried up by the wind; some gliding animals may use their gliding membranes for drag rather than lift. Gliding flight: falling at an angle less than 45° from the horizontal with lift from adapted aerofoil membranes; this allows falling directed horizontal movement, with streamlining to decrease drag forces for aerofoil efficiency and with some maneuverability in air. Gliding animals have a lower aspect ratio than true flyers. Powered flight has evolved only four times.
It uses muscular power to replace energy lost to drag. Flapping: moving wings to produce lift and thrust. May ascend without the aid of the wind, as opposed to parachuters. Ballooning and soaring are not powered by muscle, but rather by external aerodynamic sources of energy: the wind and rising thermals, respectively. Both can continue as long. Soaring is only seen in species capable of powered flight, as it requires large wings. Ballooning: being carried up into the air from the aerodynamic effect on long strands of silk in the wind. Certain silk-producing arthropods small or young spiders, secrete a special light-weight gossamer silk for ballooning, sometimes traveling great distances at high altitude. Soaring: gliding in rising or otherwise moving air that requires specific physiological and morphological adaptations that can sustain the animal aloft without flapping its wings; the rising air is due to ridge lift or other meteorological features. Under the right conditions, soaring creates a gain of altitude without expending energy.
Large wingspans are needed for efficient soaring. Many species will use multiple of these modes at various times. While gliding occurs independently from powered flight, it has some ecological advantages of its own. Gliding is a energy-efficient way of travelling from tree to tree. An argument made is that many gliding animals eat low energy foods such as leaves and are restricted to gliding because of this, whereas flying animals eat more high energy foods such as fruits and insects. In contrast to flight, gliding has evolved independently many times. Worldwide, the distribution of gliding animals is uneven as most inhabit rain forests in Southeast Asia. Additionally, a variety of gliding vertebrates are found in Africa, a family of hylids lives in South America and several species of gliding squirrels are found in the forests of northern Asia and North America. Various factors produce these disparities. In the forests of Southeast Asia, the dominant canopy trees are taller than the canopy trees of the other forests.
A higher start farther travel. Gliding predators may more efficiently search for prey; the lower abundance of insect and small vertebrate prey for carnivorous animals in Asian forests may be a factor. In Australia, many mammals possess, to prehensile tails. Powered flight has evolved unambiguously only four times—birds, bats and insects. In contrast to gliding, which has evolved more but gives rise to only a handful of species, all three extant groups of powered flyers have a huge number of species, suggesting that flight is a successful strategy once evolved. Bats, after rodents, have the most species of any mammalian order, about 20% of all mammalian species. Birds have the most species of any class of terrestrial vertebrates
The Philippine eagle known as the monkey-eating eagle or great Philippine eagle, is an eagle of the family Accipitridae endemic to forests in the Philippines. It has brown and white-coloured plumage, a shaggy crest, measures 86 to 102 cm in length and weighs 4.04 to 8.0 kg. It is considered the largest of the extant eagles in the world in terms of length and wing surface, with Steller's sea eagle and the harpy eagle being larger in terms of weight and bulk. Among the rarest and most powerful birds in the world, it has been declared the Philippine national bird, it is critically endangered due to massive loss of habitat resulting from deforestation in most of its range. Killing a Philippine eagle is punishable under Philippine law up to 12 years in prison and heavy fines; the first European to study the species was the English explorer and naturalist John Whitehead in 1896, who observed the bird and whose servant, collected the first specimen a few weeks later. The skin of the bird was sent to William Robert Ogilvie-Grant in London in 1896, who showed it off in a local restaurant and described the species a few weeks later.
Upon its scientific discovery, the Philippine eagle was first called the monkey-eating eagle because of reports from natives of Bonga, where the species was first discovered, that it preyed on monkeys. The species name commemorates the father of John Whitehead. Studies revealed, that the alleged monkey-eating eagle ate other animals, such as colugos, large snakes, monitor lizards, large birds, such as hornbills. This, coupled with the fact that the same name applied to the African crowned eagle and the Central and South American harpy eagle, resulted in a presidential proclamation to change its name to Philippine eagle in 1978, in 1995 was declared a national emblem; this species has no recognized subspecies. Apart from Philippine eagle and monkey-eating eagle, it has been called the great Philippine eagle, it has numerous names in the many Philippine languages, including ágila, háribon, banog. Use of the name "Philippine eagle" in preference of "monkey-eating eagle" was the subject of an official government proclamation by Philippine president Ferdinand Marcos in 1978.
A study of the skeletal features in 1919 led to the suggestion that the nearest relative was the harpy eagle. The species was included in the subfamily Harpiinae until a 2005 study of DNA sequences which identified them as not members of the group, finding instead, that the nearest relatives are snake eagles, such as the bateleur; the species has subsequently been placed in the subfamily Circaetinae. The Philippine eagle's nape is adorned with brown feathers that form a shaggy, manelike crest; the eagle has a creamy-brown nape and crown. The back of the Philippine eagle is dark brown, while underwings are white; the heavy legs are yellow, with large, dark claws, the prominent, high-arched, deep beak is a bluish-gray. The eagle's eyes are blue-gray. Juveniles are similar to adults; the Philippine eagle is reported as measuring 86–102 cm in total length, but a survey of several specimens from some of the largest natural history collections in the world found the average was 95 cm for males and 105 cm for females.
Based on the latter measurements, this makes it the longest extant species of eagle, as the average for the female equals the maximum reported for the harpy eagle and Steller's sea eagle. The longest Philippine eagle reported anywhere and the longest eagle outside of the extinct Haast's eagle is a specimen from Field Museum of Natural History with a length of 112 cm, but it had been kept in captivity so may not represent the wild individuals due to differences in the food availability; the level of sexual dimorphism in size is not certain, but the male is believed to be about 10% smaller than the female, this is supported by the average length provided for males and females in one source. In many of the other large eagle species, the size difference between adult females and males can exceed 20%. For adult Philippine eagles, the complete weight range has been reported as 4.7 to 8.0 kg, while others have found the average was somewhat lower than the above range would indicate, at 4.5 kg for males and 6.0 kg for females.
One male was found to weigh 4.04 kg. The Philippine eagle has a wing chord length of 57.4 -- 61.4 cm. The maximum reported weight is surpassed by two other eagles and the wings are shorter than large eagles of open country, but are quite broad; the tarsus of the Philippine eagle ties as the longest of any eagle from 12.2 to 14.5 cm long, about the same length as that of the much smaller but long-legged New Guinea eagle. The large but laterally compressed bill rivals the size of Steller's sea eagle's as the largest bill for an extant eagle, its bill averages 7.22 cm in length from the gape. The tail is long at 42–45.3 cm, while another source lists a tail length of 50 cm. The most heard noises made by the Philippine eagle are loud, high-pitched whistles ending with inf
The Triassic is a geologic period and system which spans 50.6 million years from the end of the Permian Period 251.9 million years ago, to the beginning of the Jurassic Period 201.3 Mya. The Triassic is the shortest period of the Mesozoic Era. Both the start and end of the period are marked by major extinction events. Triassic began in the wake of the Permian–Triassic extinction event, which left the Earth's biosphere impoverished. Therapsids and archosaurs were the chief terrestrial vertebrates during this time. A specialized subgroup of archosaurs, called dinosaurs, first appeared in the Late Triassic but did not become dominant until the succeeding Jurassic Period; the first true mammals, themselves a specialized subgroup of therapsids evolved during this period, as well as the first flying vertebrates, the pterosaurs, like the dinosaurs, were a specialized subgroup of archosaurs. The vast supercontinent of Pangaea existed until the mid-Triassic, after which it began to rift into two separate landmasses, Laurasia to the north and Gondwana to the south.
The global climate during the Triassic was hot and dry, with deserts spanning much of Pangaea's interior. However, the climate became more humid as Pangaea began to drift apart; the end of the period was marked by yet another major mass extinction, the Triassic–Jurassic extinction event, that wiped out many groups and allowed dinosaurs to assume dominance in the Jurassic. The Triassic was named in 1834 by Friedrich von Alberti, after the three distinct rock layers that are found throughout Germany and northwestern Europe—red beds, capped by marine limestone, followed by a series of terrestrial mud- and sandstones—called the "Trias"; the Triassic is separated into Early and Late Triassic Epochs, the corresponding rocks are referred to as Lower, Middle, or Upper Triassic. The faunal stages from the youngest to oldest are: During the Triassic all the Earth's land mass was concentrated into a single supercontinent centered more or less on the equator and spanning from pole to pole, called Pangaea.
From the east, along the equator, the Tethys sea penetrated Pangaea, causing the Paleo-Tethys Ocean to be closed. In the mid-Triassic a similar sea penetrated along the equator from the west; the remaining shores were surrounded by the world-ocean known as Panthalassa. All the deep-ocean sediments laid down during the Triassic have disappeared through subduction of oceanic plates; the supercontinent Pangaea was rifting during the Triassic—especially late in that period—but had not yet separated. The first nonmarine sediments in the rift that marks the initial break-up of Pangaea, which separated New Jersey from Morocco, are of Late Triassic age. S. these thick sediments comprise the Newark Group. Because a super-continental mass has less shoreline compared to one broken up, Triassic marine deposits are globally rare, despite their prominence in Western Europe, where the Triassic was first studied. In North America, for example, marine deposits are limited to a few exposures in the west, thus Triassic stratigraphy is based on organisms that lived in lagoons and hypersaline environments, such as Estheria crustaceans.
At the beginning of the Mesozoic Era, Africa was joined with Earth's other continents in Pangaea. Africa shared the supercontinent's uniform fauna, dominated by theropods and primitive ornithischians by the close of the Triassic period. Late Triassic fossils are more common in the south than north; the time boundary separating the Permian and Triassic marks the advent of an extinction event with global impact, although African strata from this time period have not been studied. During the Triassic peneplains are thought to have formed in what is now southern Sweden. Remnants of this peneplain can be traced as a tilted summit accordance in the Swedish West Coast. In northern Norway Triassic peneplains may have been buried in sediments to be re-exposed as coastal plains called strandflats. Dating of illite clay from a strandflat of Bømlo, southern Norway, have shown that landscape there became weathered in Late Triassic times with the landscape also being shaped during that time. At Paleorrota geopark, located in Rio Grande do Sul, the Santa Maria Formation and Caturrita Formations are exposed.
In these formations, one of the earliest dinosaurs, Staurikosaurus, as well as the mammal ancestors Brasilitherium and Brasilodon have been discovered. The Triassic continental interior climate was hot and dry, so that typical deposits are red bed sandstones and evaporites. There is no evidence of glaciation near either pole. Pangaea's large size limited the moderating effect of the global ocean; the strong contrast between the Pangea supercontinent and the global ocean triggered intense cross-equatorial monsoons. The Triassic may have been a dry period, but evidence exists that it was punctuated by several episodes of increased rainfall in tropical and subtropical latitudes of the Tethys Sea and its surrounding land. Sediments and fossils suggestive of a more humid climate are known from the Anisian to Ladinian of the Tethysian domain, from the Carnian and Rhaetian of a larger area that includes the Boreal domain, the North
Sunda flying lemur
The Sunda flying lemur or Sunda colugo known as the Malayan flying lemur or Malayan colugo, is a species of colugo. Until it was thought to be one of only two species of flying lemur, the other being the Philippine flying lemur, found only in the Philippines; the Sunda flying lemur is found throughout Southeast Asia in Indonesia, Thailand and Singapore. The Sunda flying lemur does not fly. Instead, it glides, it is arboreal, is active at night, feeds on soft plant parts such as young leaves, shoots and fruits. After a 60-day gestation period, a single offspring is carried on the mother's abdomen held by a large skin membrane, it is a forest-dependent species. The head-body length of Sunda flying lemur is about 33 to 42 cm, its tail length measures 18 to 27 cm, its weight is 0.9 to 1.3 kg. The Sunda flying lemur is protected by national legislation. In addition to deforestation and loss of habitat, local subsistence hunting poses a serious threat to this animal. Competition with the plantain squirrel represents another challenge for this species.
More information is needed on population declines, but at present, the rate of the decline is not believed to merit listing in any category lower than Least Concern. The Sunda flying lemurs' two forms are not morphologically distinct from one another; the Laos specimen is smaller than the other known mainland population. Despite the large and dwarf forms, four subspecies are known: G. v. variegatus, G. v. temminckii, G. v. borneanus, G. v. peninsulae incorporating on the genetic species concept due to geographic isolation and genetic divergence. Recent molecular and morphological data provide the evidence that the mainland and Bornean Sunda flying lemur subspecies may be recognised as three separate species in the genus Galeopterus. Sunda flying lemurs live either solitary or in small groups, they can be territorial as regards sleeping areas. They are nocturnal, they are arboreal and in the daytime, they sleep high within dense foliage in the treetops or in holes in trees. With all four of their feet, they cling on to the underside of branches.
Climbing involves stretching out their two front legs and bringing up their two back legs, which results in an awkward hopping. They can glide more than 100 m with minimal loss in elevation; when threatened they either climb higher up or remain motionless. These animals are quite helpless if on the forest floor; the Sunda flying lemur is helpless when on the ground. Its gliding membrane connects from the neck, extending along the limbs to the tips of the fingers and nails; this kite-shaped skin is known as a patagium, expanded for gliding. It can glide over a distance of 100 m with a loss of fewer than 10 m in elevation, it can maneuver and navigate while gliding, but strong rain and wind can affect its ability to glide. Gliding occurs in open areas or high in the canopy in dense tropical rainforest; the Sunda flying lemur needs a certain distance to land to avoid injury. The highest landing forces are experienced after short glides; the ability to glide increases a colugo's access to scattered food resources in the rainforest, without increasing exposure to terrestrial or arboreal predators.
In general, the diet of the Sunda flying lemur consists of leaves. It consumes leaves with less potassium and nitrogen-containing compounds, but with higher tannin, it feeds on buds, coconut flowers, durian flowers and sap from selected tree species. It feeds on insects in Sarawak, Malaysian Borneo; the selected food sources depend on the localities, vegetation types, availability. The Sunda flying lemur forages in tree canopies, it may forage on a single species. It can be seen licking tree bark of selected tree species to obtain water, nutrients and minerals. Though the Sunda flying lemur has been reported to occur in gardens and plantations, the species resides in forests primarily; the Sunda flying lemur is distributed throughout Southeast Asia, ranging from the Sunda Shelf mainland to other islands – Northern Laos, Vietnam, Malaysia, Brunei and many adjacent islands. Conversely, the Philippine flying lemur is confined to the southern parts of the Philippines only; the Sunda flying lemur is adapted to many different vegetation types, including gardens and secondary forest and coconut plantations, fruit orchards, mangrove swamps and upland forests, tree plantations, lowland dipterocarp forests, mountainous areas.
However, not all of the mentioned habitats can sustain large colugo populations. View the galVar1 genome assembly in the UCSC Genome Browser