Giganotosaurus


Giganotosaurus is a genus of carcharodontosaurid dinosaur that lived 98 to 96 million years ago during the early Cenomanian stage of the Late Cretaceous Period. It is one of the largest known terrestrial carnivores, slightly larger than Tyrannosaurus, but smaller than Spinosaurus. Its fossils have been found in Argentina.
The longgest meat-eating dinosaur yet discovered is Giganotosaurus, a 44-46 ft (13.5-14.3 m) long behemoth, who weighed about 8 tons and stood 12 feet tall (at the hips). It walked on two legs, had a brain the size of a banana, and had enormous jaws with 8-inch long serrated teeth in a 6-foot (1.8 m) long skull.
G. carolinii was slightly larger than T. rex, but had a brain only about half as big as those of tyrannosaurids. The teeth of Tyrannosaurus were longer and wider, but more variable in size. The teeth of Giganotosaurus were shorter, less variable and narrower than those of Tyrannosaurus, and were more adapted for slicing flesh. A well-developed olfactory region means that it probably had a good sense of smell. Its skull, although large, had a slender build.

Giganotosaurus stalking to Titanosaurius

Pareiasaurus


Pareiasaurus large quadruped, about 2.5 metres (8.2 ft) long, with elephantine legs, walking in a typically reptilian posture. Its skull had several spine- and wart-like protrusions. The scales may have provided some protection against predators. Pareiasaurus's leaf-shaped teeth, ideal for biting through tough plant fibers, indicate it was a herbivore. Even the palate had teeth.
Pareiasaurus is an extinct genus of anapsid reptile from the Permian period. It was a typical member of its family, the pareiasaurs, which take their name from this genus.

Pareiasaurs appear very suddenly in the fossil record. It is clear that these animals evolved from Rhipaeosaurs to fill the large herbivore niche (or guild) that had been occupied early in the Permian period by the Caesid pelycosaurs and before then the Diadectid amphibians and Edaphosaur reptiles. In fact it may well have been the extinction of the Caesids created an ecological vacuum that enabled the Pareiasaurs to appear and suddenly diversify as rapidly as they did (within the span of only two million years).

It has been often suggested that these animals were semi-aquatic.

It has recently been argued that Pareiasaurs may have evolved into turtles. They had turtle-like skull features, and several genera had bony plates in the skin, possibly the first signs of a turtle shell. However, the case for turtle ancestry is not proven.

Probably, the Pareiasaurus were the victims of Titanophoneus.

Titanoboa

By comparing the sizes and shapes of its fossilized vertebrae to those of extant snakes, researchers estimated that the T. cerrejonensis reached a maximum length of 12 to 15 metres (40 to 50 ft), weighed about 1,135 kilograms (2,500 lb), and measured about 1 metre (40 in) in diameter at the thickest part of the body.

The largest eight of the 28 T. cerrejonensis snakes found were between 12 and 15 metres (39 and 49 ft) in length. In comparison, the largest extant snakes are the Python reticulatus, which measures about 9 metres (30 ft) long, and the anaconda, which measures about 7.5 metres (25 ft) long and is considered the heaviest snake on Earth. At the other end of the scale, the smallest extant snake is Leptotyphlops carlae with a length of about 10 centimetres (4 in).



Titanoboa, pronounced , meaning "titanic boa", was a genus of snake that lived approximately 60 to 58 million years ago, in the Paleocene epoch,a 10-million-year period immediately following the dinosaur extinction event. The only known species is the Titanoboa cerrejonensis, the largest snake ever discovered.

Arctodus simus or giant short-faced bear


Arctodus — known as the short-faced bear or bulldog bear — is an extinct genus of bear consisting of two known fossil species: Arctodus simus and Arctodus pristinus. They were native to North America during the middle to late Pleistocene epoch. It was thought to be carnivorous, though like modern bears, it was probably not above meal of any kind. Its bones were long and thin, and it believed to be able to run up to 50 km/h for short distances. It was large creature, and likely the apex predator of its day and location. Its large size, combined with the natural toughness of bears, meant that it probably preyed upon the North American megafauna.

However, relying on the North American megafauna as its main food source, it disappeared at the same time they did, possibly partly due to competition with humans for the same limited game.

Tremarctos ornatus, the spectacled bear of South America, is the closest living relative of the short-faced bears.

Arctodus simus, also known as the giant short-faced bear, is an extinct species of bear. The genus Arctodus is known as the short-faced or bulldog bears. A. simus is the largest bear, and more generally, the largest mammalian land carnivore within the last 20,000 years. It was native to prehistoric North America from about 800 thousand years ago, and became extinct about 12,500 years ago. It was the largest terrestrial carnivore of its day. The largest mature males would have stood 1.8m (6 ft) at the shoulder (on all fours), 4m (13 ft) upright and an impressive 900kg (2000 lb).


Arctodus simus are a scavenging or necrophagy, they were using its enormous size to intimidate smaller predators such as dire wolves, Smilodon and American lions from their kills.

Arsinoitherium, the cousin of the elephant.


When alive, it would have superficially resembled a rhinoceros, and have been about 1.8 metres (5.9 ft) tall at the shoulders, and 3 metres (9.8 ft) long. The most noticeable feature of Arsinoitherium was a pair of enormous knife-like horns with cores of solid bone that projected from above the nose, and a second pair of tiny, knob-like horns on top of the head, immediately behind the larger horns. The skeleton is robust but shows that it was descended from a cursorial ancestor, and that the beast may have been able to run if it had to, like a modern elephant or rhinoceros. Its limb bones also suggest that the columnar legs of the living animal were elephant-like (especially since they ended in five-toed feet), rather than rhinoceros-like. Arsinoitherium had a full complement of 44 teeth, which is the primitive state of placental mammalian dentition, suggesting that it was a selective browser. The large size and hefty build of Arsinoitherium would have rendered it largely immune to predation. However, creodonts may have preyed on the young or infirm.


Arsinoitherium is an extinct genus of paenungulate mammal related to elephants, and hyraxes (Embrithopoda). These species were rhinoceros-like herbivores that lived during the late Eocene and the early Oligocene, from 36 to 30 million years ago, in areas of tropical rainforest, and at the margin of swamps.

Elasmotherium and the origen of unicorn


Elasmotherium ("Thin Plate Beast") was a genus of giant rhinoceros which stood, on average, 2.7 metres (8.9 ft) high and 6 metres (20 ft) long, with a single two-meter-long horn in the forehead. The animal may have weighed up to 5 tonnes (5.5 short tons). Its legs were longer than those of other rhinos and were designed for galloping, giving it a horse-like gait. It was probably a fast runner, in spite of its size. Its teeth were similar to those of horses, and it probably grazed low herbs.

The genus appeared during the Late Pliocene in Central Asia, being derived from the genus Sinotherium. E. inexpectatum and E. peii inhabited Eastern China during the Upper Pliocene to Early Pleistocene. They disappeared approximately 1.6 Ma.

Morphological peculiarities of elasmotherians have generated two main hypotheses concerning their appearance and the character of their habitat. The first, most widely accepted view[citation needed] which was also described above, portrays them as large woolly animals with a large forehead horn that thrived on an open steppe. Fossils of the horn, however, have not been found. The other view[citation needed] assigns elasmotherians to riparian biotopes. It is probable that elasmotherians dwelt in both riparian and steppe biotope[citation needed]. The riparian biotope is suggested by dental and skull morphology. The combination of such characteristics as the absence of canines and strongly developed lateral processes of the atlas implies lateral movements of the head, presumably for grasping grass. The hypsodont dentition indicates presence of mineral grains in the food. Such food could be obtained by pulling out dense plants from the moist soil. These conditions are typical for riparian biotopes. On the other hand, a steppe biotope is indicated by their rather long and slender limbs, which would have served well for creatures grazing over vast areas.

It is believed that Elasmotherium died out in prehistoric times. However, according to science writer and cryptozoologist Willy Ley, the animal may have survived long enough to be remembered in the legends of the Evenk people of Russia as a huge black bull with a single horn in the forehead.

There is also a testimony by the medieval traveller Ibn Fadlan which has been interpreted by some[who?] to indicate that Elasmotherium may have survived into historical times.

Amphicoelias fragillimus,possibly the biggest terrestrial animal of the history.


Amphicoelias (pronounced /ˌæmfɨˈsiːliəs/, meaning 'doubly hollow', from the Greek amphi: "on both sides", and koilos: "hollow, concave") is a genus of herbivorous sauropod dinosaur that includes what may be the largest dinosaur ever discovered, A. fragillimus. Based on surviving descriptions of a single fossil bone, A. fragillimus may have been the longest known vertebrate at 40–60 meters (131–196 ft) in length, and may have had a mass of up to 122 metric tons (135 short tons), rivaling the heaviest animal known, the Blue Whale. However, because the only fossil remains were lost at some point after being studied and described in the 1870s, evidence survives only in drawings and field notes.

Carpenter examined the paleobiology of giant sauropods, including Amphicoelias, and addresses the question of why this group attained such a huge size. He pointed out that gigantic sizes were reached early in sauropod evolution, with very large sized species present as early as the late Triassic Period, and concluded that whatever evolutionary pressure caused large size was present from the early origins of the group. Carpenter cited several studies of giant mammalian herbivores, such as elephants and rhinoceros, which showed that larger size in plant-eating animals leads to greater efficiency in digesting food. Since larger animals have longer digestive systems, food is kept in digestion for significantly longer periods of time, allowing large animals to survive on lower-quality food sources. This is especially true of animals with a large number of 'fermentation chambers' along the intestine which allow microbes to accumulate and ferment plant material, aiding digestion. Throughout their evolutionary history, sauropod dinosaurs were found primarily in semi-arid, seasonally dry environments, with a corresponding seasonal drop in the quality of food during the dry season. The environment of Amphicoelias was essentially a savanna, similar to the arid environments in which modern giant herbivores are found, supporting the idea that poor-quality food in an arid environment promotes the evolution of giant herbivores. Carpenter argued that other benefits of large size, such as relative immunity from predators, lower energy expenditure, and longer life span, are probably secondary advantages.

Azhdarchidae, giant pterodactyl


Azhdarchidae (from Ajdarxo, the name of a dragon in Uzbek mythology, derived from the Persian Aži Dahāka) is a family of pterosaurs known primarily from the late Cretaceous Period, and which included some of the largest known flying animals of all time. Originally considered a sub-family of Pteranodontidae, Nesov (1984) named the azhdarchinae to include the pterosaurs Azhdarcho, Quetzalcoatlus, and "Titanopteryx" (now known as Arambourgiania). Azhdarchids are characterized by their long legs and extremely long necks, made up of elongated neck vertebrae which are round in cross section. Most species of azhdarchids are still known mainly from their distinctive neck bones and not much else. The few azhdarchids that are known from reasonably good skeletons include Zhejiangopterus and Quetzalcoatlus. Azhdarchids are also distinguished by their relatively large heads and long, spear-like jaws. It had been suggested azhdarchids were skimmers, but further research has cast doubt on this idea, demonstrating that azhdarchids lacked the necessary adaptations for a skim-feeding lifestyle, and that they may have led a more terrestrial existence similar to modern storks.

Argentavis magnificens is the largest flying bird ever discovered.


This bird, sometimes called the Giant Teratorn, is an extinct species known (as of 2006) from three sites from the late Miocene (6 million years before present) of central and northwestern Argentina, where a good sample of fossils has been obtained.[1]

The humerus (upper arm bone) of Argentavis is somewhat damaged. It allows a fairly accurate estimate of its length in life, which was a bit shorter than an entire human arm.[2] The species apparently had stout, strong legs and large feet which enabled it to walk with ease. The bill was large, rather slender, had a hooked tip with a wide gape.

Currently accepted estimates:

Wingspan: 5.8–8 m (19 – 26 ft)
Wing area: nearly 7 m² (75 square ft)
Wing loading: c. 11.5 kg/m²
Length: 3.5 m (11.5 ft)
Height: 1.7–2 m (5.6–6.5 ft)
Weight: 60–80 kg (140–180 lb)
For comparison, the living bird with the largest wingspan is the Wandering Albatross (3.63 m). Since A. magnificens is known to have been a land bird, another good point of comparison is the Andean Condor, which is not too distantly related to Argentavis. This bird is among the largest land birds, with a wingspan of about 3 m and weighing up to 12 kg.

The ability to fly is not a simple question of weight, except in extreme cases. Size and structure of the wing must also be taken into account. As a rule of thumb, a wing loading of 25 kg/m² is considered the limit for avian flight.[3]



The heaviest extant flying bird is not heavier than 20 kg (there are several contenders, among which are the European Great Bustard and the African Kori Bustard). The Sarus Crane is the tallest flying bird alive, standing nearly as high as Argentavis due to its long legs.

The largest known flying creatures are a group of pterosaurs named azhdarchids, extinct flying animals that existed during the age of the dinosaurs and died out at the end of the Cretaceous. Estimations of the wingspan of the largest species like Quetzalcoatlus and Hatzegopteryx exceeds 10 m, with less conservative estimates being 12 m or more.

Microraptor.


Microraptor provides important evidence about the evolutionary relationship between birds and dinosaurs. Microraptor had long pennaceous feathers that form wing-like surfaces on the arms and tail but also, surprisingly, on the legs. This led Xu (2003) to describe it as a "four winged dinosaur", and to speculate that it may have glided using all four limbs for lift. Two species have been named, M. zhaoianus and M. gui. It has recently been suggested that all of the specimens belong to a single species, which is properly called M. zhaoianus. Cryptovolans, another four-winged dromaeosaur, may also be a species of Microraptor.
With adult specimens ranging 42–83 centimeters (1.4–2 ft) long, and with a weight estimated at up to 1 kilogram, Microraptor was among the smallest known dinosaurs. Aside from its extremely small size, Microraptor was among the first non-avian dinosaurs discovered with the impressions of feathers and wings.



, Microraptor is one of the few known bird precursors to sport long flight feathers on its feet as well as its forearms and hands. Their bodies had a thick covering of feathers, with a diamond-shaped fan on the end of the tail (possibly for added stability during flight). Xu et al. (2003) compared the longer plumes on Microraptor's head to those of the Philippine Eagle. Bands of dark and light present on some specimens may indicate color patterns present in life. Several anatomical features found in Microraptor, such as a combination of unserrated and partially serrated teeth with constricted 'waists', and unusually long upper arm bones, are shared with both primitive avians and primitive troodontids. Microraptor is particularly similar to the basal troodontid Sinovenator; in their 2002 description of two M. zhaoianus specimens, Hwang et al. note that this is not particularly surprising, given that both Microraptor and Sinovenator are very primitive members of two closely related groups, and both are close to the deinonychosaurian split between dromaeosaurids and troodontids.
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