Josephoartigasia monesi



Josephoartigasia monesi was a giant prehistoric rodent from the Pliocene, the largest known to date. It is estimated that between four and lived two million years in what is now Uruguay. It is an extinct species of rodent and as said the largest rodent in history.

The species measured approximately 3 m long and 1.5 m high. In life they were about the size of a car. Their incisors were more than 30 cm long. The animal weighed about a ton, and fed on soft grasses.

The fossil (the skull), more than half a meter, it belonged to a species closely related to the current hamsters, and found the first skull of an animal that was known to have existed but over which he had of remains found.

Among their predators can find the cave lion and Smilodon.

Velociraptor.



To be a Velociraptor dromaeosaurid was relatively small, the adults reach a length of 2 m, and approximately 0.5 meters in height at the hip, and weighing about 15 kg. The skull, about 25 cm long, was uniquely up-curved, with a concave upper surface and a convex bottom. The jaws were lined with 26 or 28 teeth on each side, the rear edge of each tooth was markedly serrated.
But of all the features that made the Velociraptor a murderer efficient and sharp curved claws were the most dangerous. Located on the second toe of each foot, these claws were a fine point and were flattened laterally, like the claws of a cat. When the Velociraptor ran, stretched claws held back so as not touching the ground and did not lose their edge.
When the Velociraptor attack, the claw could project forward and down while HADB a strong kick. Thus, the claw could act as a razor-sharp knife and result in protracted and deep cuts in their prey, probably bleed to death.
Velociraptor is well known in his role as a cruel and cunning murderer may attack small offspring from larger dinosaurs such as Triceratops.

Velociraptor (meaning "swift thief") in Castilian Velociraptor, is a dromaeosaurid theropod dinosaur that lived during the Campanian to the late Cretaceous period, makes about 70 to 65 million years. On the mainland, which is in Europe and Asia.

Iguanodon


This was a robust animal prehistoric herbivore that could switch between bipedal to quadrupedal. The well-known species, I. bernissartensis, it is estimated that weighed about 3 tons on average, and measure about 10 feet long when adult, with some specimens possibly would have reached 13 meters.
The arms were long, up to 75% of the length of the legs with inflexible hands built so that the three central fingers could bear weight.

One of the first details on the iguanodons noticed was that I had reptile herbivore teeth (Iguanodon means "Iguana tooth" as they were of a similar but larger and with a greater destructive capacity) although there was not always consensus on how to eat .

There is no evidence to support a sexual dimorphism, as in hadrosaurs and Ceratopsia.

It is thought that they lived in herds of several dozen individuals as fossils have been found in certain circumstances, several bodies Iguanadon in ancient lakes or rivers, possibly due to the flood of these during migration.

They lived in the early Cretaceous period, makes about 130 to 120 million years (mong the Berriasian and Aptian) in what is now Europe. And in North America.



The scion of thumb is one of the best known features of the iguanodons. Yet it was placed, initially, in the nose by Mantell. When they found the complete copies in Bernissart Dollo realized the mistake and I put in place fingerprint, thumb amended.

Triceratops


Individual Triceratops are estimated to have reached about 7.9 to 9.0 m (26.0–29.5 ft) in length, 2.9 to 3.0 m (9.5–9.8 ft) in height, and 6.1–12.0 tonnes (13,000-26,000 lb) in weight. The most distinctive feature is their large skull, among the largest of all land animals. It could grow to be over 2 m (7 ft) in length, and could reach almost a third of the length of the entire animal. It bore a single horn on the snout, above the nostrils, and a pair of horns approximately 1 m (3 ft) long, with one above each eye. To the rear of the skull was a relatively short, bony frill. Most other ceratopsids had large fenestrae in their frills, while those of Triceratops were noticeably solid.

Triceratops species possessed a sturdy build, with strong limbs and short five-hoofed hands and four-hoofed feet. Although certainly quadrupedal, the posture of these dinosaurs has long been the subject of some debate. Originally, it was believed that the front legs of the animal had to be sprawling at angles from the thorax, in order to better bear the weight of the head.

Triceratops is a genus of herbivorous ceratopsid dinosaur which lived during the late Maastrichtian stage of the Late Cretaceous Period, around 68 to 65 million years ago (mya) in what is now North America.

Allosaurus Europaeus.


Allosaurus was a large bipedal predator with a large skull, equipped with dozens of large, sharp teeth. It averaged 8.5 meters (28 ft) in length, though fragmentary remains suggest it could have reached over 12 meters (39 ft). Relative to the large and powerful hindlimbs, its three-fingered forelimbs were small, and the body was balanced by a long, heavy tail.

Allosaurus fragilis, the best-known species, had an average length of 8.5 meters (28 ft), with the largest definitive Allosaurus specimen estimated at 9.7 meters long (32 ft), and an estimated weight of 2.3 metric tons (2.5 short tons).

The skull and teeth of Allosaurus were modestly proportioned for a theropod of its size.

Allosaurus is a genus of large theropod dinosaur that lived 155 to 145 million years ago, in the late Jurassic period in the Kimmeridgian and Tithonian, in what is now North America and Europe.

Diplocaulus


Diplocaulus is an extinct genus of Leponspondyl amphibian who lived in the early Permian period, 270 million years ago. They had a arrow-shaped head, suggesting that this might have served better to swim in the water by moving the water to the sides like a shark or that depredadrores could not swallow. They measured about one meter in length. The first specimen was discovered in 1877 by Edward Cope in Texas called "Bone Wars".
This prehistoric animal ate fish and insects, and lived near water because it was an amphibian and used water as a roast for her eggs.
It looks like the Gerrothorax, sharing certain characteristics suchas this head shape, somewhat more pronounced in the Diplocaulus and eyes in a higher position inthe head.

Gerrothorax


Gerrothorax is an extinct genus of amphibian temnospondyl who lived in the late Triassic period (about 210 million years ago) in what is now Germany and Greenland. Reached an approximate length of 1 meter. Their bodies are flattened, suggesting they were hiding under the sand or mud at the bottom of rivers and lakes as potential victims stalked her large eyes focused upward. The skull had a peculiar way with angular protrusions on both sides. This geometry of the skull is reminiscent of the genus Diplocaulus, but less developed.

Fossils show that the species of this genus were pedomórficas, keeping three pairs of gills also in the adult stage, which allowed them to breathe underwater. This feature also found in some current caudate, as in certain species of the family and Ambystomatidae Mudpuppy.


Curiosity: The lower jaw was fixed Gerrothorax and chewing had to raise his head and drop it. That is, exactly the opposite of what we do and almost all the animals of creation.

Hyracotherium

Hyracotherium (beast like a Hyrax), also known as Eohippus, is a genus of mammal Perissodactyla Palaeotheriidae family.

It is considered an ancestor of the horse, rhinoceros and tapir. It is a quadruped animal that lived in the Northern Hemisphere (Asia, Europe and North America) during the Eocene period, makes 60 to 45 million years. The line to the existing horse evolució through the following animals Preistorica: Oligohippus, Merichippus, Pliohippus. In chronological order.



Hyracotherium was a small herbivore the size of a fox, media cross about 35 inches and weighed 6 kg, had four toes on the forefeet and three on hind paws protected, the central one being longer. These animals were already clearly like the horse, despite its small size and probably lived in forests browsing. His teeth were adapted for the consumption of young leaves of the bushes and his eyes were different from modern horses as they were located more to the center of the head preventing a good side vision (which in the modern horse serves as defensive system), Eohippus but did not need because in the jungle environment in which they lived, was more effective camouflage to avoid predators.

Entelodont


The entelodont is an extinct family of hoofed mammals related to the current pig and animals with hooves. Distributed in Asia and North America made between 45 and 25 million years. Measured about 2,1 m (7 feet) high, 3 `5 meters (14 feet)long and had a brain the size of a fist. It fed on carrion, oportunisatas, and plants. Not rule out the flush of live prey. Your lifestyle should look like pigs. Believed to be a omnivore because their teeth had large teeth and powerful back teeth. Like the pigs had a heavy body and short legs and a robust and thin.
With a size similar to Hyaenodon and weighing about 4,207 kg (9,300 lb) was the only rival of Hyaenodon.
For the morphological differences between male and female remains, it is believed that males were competing to win the group severamete females.

Hyaenodon.


Hyaenodon ( 'hyena's tooth ") is an extinct genus of mammals of the order of creodonts. Some species of this genus were among the largest terrestrial carnivorous mammals.

These predators were as big as a rhinoceros. Appeared in the late Eocene 41 million years ago, during the Oligocene to exist 21 million years ago.

Was the dominant predator of the time, even have discovered remains of saber-toothed feline powerful victim Hyaenodon.

The name "hyena teeth" refers to its pontente bite and hardness of his teeth. Being able to eat all parts of the dam, including the teeth.

His skull was long and narrow. The body was similar to the recently extinct Tasmanian wolf, Thylacinus. But larger.

At the time competed against Entelodon. I put a video showing that competition for food.


Glyptodon



The glyptodon, always connected with existing armadillos, a native of America. The glyptodon measured about 3 m and weighed about 1.4 t, being equivalent in size and shape to a Volkswagen Beetle. It was a herbivore and, by its constitution, it is assumed that it was not very agile. His defense against predators was based on its rigid shell. Different species are distinguished by different types of shells. Many of these shells remained empty throughout the plains of Uruguay and Argentina will likely serve as a refuge for early humans in the region.

The glyptodon is part of the group of placental mammals known as Xenarthra. This order of mammals includes armadillos, as well as several extinct species.

The glyptodon emerged in the Pliocene in South America, migrating north after, when the Isthmus of Panama joined the Americas. It is believed that they were hunted by human populations in their environment, to use the carcasses of dead animals as a refuge from hostile environments. Became extinct about 10,000 to 8,500 years.



The glyptodontes oldest known lived in the early Tertiary and were not very large. After appearing species were becoming larger, until in the Quaternary, when there were also megatherium, there were real giants who roamed in what is now Patagonia Argentina. They had a great half-shell shaped eggshell consists of many hexagonal shaped plates, round, etc.., He was locked below the animal's body with a sturdy skeleton, had a long tail, some species, finished off with barbed thick and compact.

Pterodactylus.



Pterodactylus is a genus of pterosaur (the first to be named and identified as a flying reptile) that lived during the late Jurassic Period. Fossils have been discovered in Europe and Africa.Its name refers to the long finger that holds the wing-like membrane bats. It was a carnivore and probably preyed upon fish and other small animals.

Pterodactylus was a relatively small pterosaur genus, with adult wingspans ranging from 50 centimeters (1.5 ft) in P. kochi to 2.4 meters (8 ft) in P. grandis

Pterodactylus was found to have a striated soft-tissue crest on the skull. Soft tissue impressions also showed unusually long, sharp, and recurved keratin sheaths on its claws. It was covered in hair-like integument, with a mane of longer hair running down the back of its neck.



http://en.wikipedia.org/wiki/Pterodactylus

Theriodontia


The teriodontes or teriodontos are named after the huge size and could reach the teeth of some of its species, mainly carnivorous, the Late Triassic had led an organization very similar to that of mammals. The temporal fossa was widening to allow the accommodation of large jaw muscles so that the hole reached the parietal and squamosal bones and postorbitario no longer be above it, and finally, the bar itself postorbitaria was incomplete leading to the typical mammalian condition in which the orbit and temporal fossa are fused.

The teriodontes or teriodontos (Theriodont, gr. "Beast's teeth") are a clade of therapsids ( "reptiles" mammal) that lived from the Permian to the Cretaceous.

This group was characterized by the lower jaw articulates with the skull bone in the small square by looking through powerful muscle bundles that made possible a wide range of yawn, making possible the emergence of species with huge teeth, as was the case of gorgonópsidos, the first known saber-toothed.

The special importance of this bone is not his presence, but its evolution along the jaw bone, which eventually forming the chain of middle ear bones of mammals. However, there is no evidence of secondary palate. The forelimbs are extensible and later also have the ability to erect posture.

The Theriocephaly, which started its development almost simultaneously to gorgonópsidos, also had additional features similar to mammals, as is the number of phalanges of the hand and foot, with a formula of 2.3.3.3.3, typical of mammals and that is what continues to hold the primates, including humans.

Spinosaurus vs Tiranosaurius Rex



T. Rex.
The tiranosaurius measured approximately 14 m in length.
He came to 5.6 meters.
An estimated weight of 6t.
T. rex had a large skull of 1.60 m fitted with eye and nasal fenestrae.
The neck was thick, muscular and short. It is said that the tyrannosaurus rex was the most fierce and powerful animal that has existed throughout history.
Period: Late Cretaceous


Spinosaurus.
The Spinosaurus measured approximately 15 meters in length.
Reach about 10 meters in height.
Its estimated weight was 7 tons.
Characteristic for its speed and agility that jutted out of his muscular legs and strong forearms equipped with huge claws, his nose was specialized for a quick bite at key locations and their body shape was aerodynamics.
Time: Cretaceous about 95 and 93 million years

For those who see Ice Age III, the great struggle is unleashed between the two titans.


Jurasic Park III

Dunkleosteus


Dunkleosteus, measuring up to 10 metres (33 ft) and weighing 3.6 tonnes (4.0 short tons), was a hypercarnivorous apex predator. Few other placoderms, save, perhaps, its contemporary, Titanichthys, rivaled Dunkleosteus in size.

Instead teeth, Dunkleosteus possessed two pairs of sharp gnathal plates which formed a beak. After studying a biomechanical model of the fish's jaws, scientists at the Field Museum of Natural History and the University of Chicago concluded that Dunkleosteus had the most powerful bite of any fish, With the exception of the Pliocene shark Megalodon.

Due to its heavily armoured nature, Dunkleosteus was likely a relatively slow (albeit powerful) swimmer. It is presumed to have dwelled in diverse zones of inshore waters, although it is unknown whether or not it was also somewhat pelagic, that is, swimming freely in open ocean.

Dunkleosteus had the most powerful bite of any fish, With the exception of the Pliocene shark Megalodon.

Dunkleosteus lived during the Devonian period, about 380-360 million years ago.

Mosasaurus


Mosasaurus was among the last mosasaur genera, and among the largest. The skull was more robustly built than other mosasaurs, as the mandibles articulated very tightly with the skull. It had a deep, barrel-shaped body, and with its fairly large eyes, poor binocular vision, and poorly developed olfactory bulbs, experts believe that Mosasaurus lived near the ocean surface, where it preyed on fish, turtles, ammonites, and possibly smaller mosasaurs. The animal remained near the surface and although it was able to dive, it evidentially did not venture into deeper waters.

The skull of Mosasaurus tapered off into a short, conical process, and the jaws were armed with massive, sharp, conical teeth. Their paddle-like limbs had five digits in front and four in back. The trunk terminated in a strong tail which, together with serpentine undulation of the whole body, contributed far more to the animal's locomotion that did the limbs.

Because of its robust skull and tightly articulating jaws, Mosasaurus was unable to swallow prey-items whole in the manner of earlier mosasaurs, such as Tylosaurus[citation needed]. Instead, with the aid of its curved, knife-like teeth, Mosasaurus was able to tear its prey into more manageable pieces that could be more easily swallowed.

Mosasaurus ("lizard of the Meuse River") was a genus of mosasaur, a carnivorous, aquatic lizard, somewhat resembling a flippered crocodile, with elongated heavy jaws. The genus lived in the Maastrichtian age of the Cretaceous period (Mesozoic era), around 70-65 millions years ago in the area of modern Western Europe.



As with most mosasaurs, their legs and feet are modified into hydrofoil-like flippers, with the forelimbs larger than the hindlimbs. Like its American relatives Tylosaurus and Hainosaurus, Mosasaurus reached lengths of about 17 meters.

Allosaurus.



Allosaurus fragilis had an average length of 8.5 meters (28 ft), with the largest definitive Allosaurus specimen (AMNH 680) estimated at 9.7 meters long (32 ft), and an estimated weight of 2.3 metric tons (2.5 short tons).Allosaurus was a typical large theropod, having a massive skull on a short neck, a long tail and reduced forelimbs. As with dinosaurs in general, weight estimates are debatable, and since 1980 have ranged between 1500 kilograms (3300 lb), 1000 to 4000 kilograms (2200 to 8800 lb), and 1010 kilograms (2230 lb) for modal adult weight (not maximum).

Several gigantic specimens have been attributed to Allosaurus, but may in fact belong to other genera. The closely related genus Saurophaganax (OMNH 1708) reached perhaps 10.9 meters (36 ft) in length, and its single species has sometimes been included in the genus Allosaurus as Allosaurus maximus, though recent studies support it as a separate genus. Another potential specimen of Allosaurus, once assigned to the genus Epanterias (AMNH 5767), may have measured 12.1 meters in length (40 ft). A more recent discovery is a partial skeleton from the Peterson Quarry in Morrison rocks of New Mexico; this large allosaurid may be another individual of Saurophaganx.


Skull

Skull of the Allosaurus fragilis skeleton mounted in the lobby of the San Diego Natural History Museum. The skull and teeth of Allosaurus were modestly proportioned for a theropod of its size. Paleontologist Gregory S. Paul gives a length of 845 millimeters (33.3 in) for a skull belonging to an individual he estimates at 7.9 meters long (26 ft). Each premaxilla (the bones that formed the tip of the snout), held five teeth with D-shaped cross-sections, and each maxilla (the main tooth-bearing bones in the upper jaw) had between fourteen and seventeen teeth; the number of teeth does not exactly correspond to the size of the bone. Each dentary (the tooth-bearing bone of the lower jaw) had between fourteen and seventeen teeth, with an average count of sixteen.

The skull had a pair of horns above and in front of the eyes. These horns were composed of extensions of the lacrimal bones,and varied in shape and size. There were also lower paired ridges running along the top edges of the nasal bones that led into the horns. The horns were probably covered in a keratin sheath and may have had a variety of functions, including acting as sunshades for the eye, being used for display, and being used in combat against other members of the same species (although they were fragile). There was a ridge along the back of the skull roof for muscle attachment, as is also seen in tyrannosaurids.


Allosaurus is a genus of large theropod dinosaur that lived 155 to 145 million years ago, in the late Jurassic period (Kimmeridgian to Tithonian). The name Allosaurus means "different lizard" and is derived from the Greek αλλος/allos ("different, strange") and σαυρος/sauros ("lizard"). The first remains that can definitely be ascribed to this genus were described in 1877 by Othniel Charles Marsh. As one of the first well-known theropod dinosaurs, it has long attracted attention outside of paleontological circles, and has been a lead dinosaur in several films and documentaries.

Allosaurus was a large bipedal predator with a large skull, equipped with dozens of large, sharp teeth. The preys of the Allosaurus were the Diplodocus or Stegosaurus.

Miacis


Miacis is an extinct that appeared in the late Paleocene (ca. 60-55 million years ago) and are mammals of the family Miacidae. They are representative of the group of early carnivores that were the ancestors of the modern Order Carnivora, although only the species Miacis cognitus is a true carnivoran. Thus, Miacis may be considered the genus of carnivorous mammals that gave rise to all modern Carnivora (dogs and cats).

Miacis was about the size of a weasel (~30 cm), and lived on the North American and European continents. They retained some of the primitive characteristics that were present in the Creodonts, the sister order of Carnivora, such as low skulls, long slender bodies, long tails, and short legs. It retained the same number of teeth, 44, although some reductions in this number were apparently in progress and some of the teeth were reduced in size.

The hind limbs were longer than the forelimbs, the pelvis was very doglike in form and structure, and some specialized traits were present in the vertebrae. It had retractable claws, agile joints for climbing, and binocular vision. Miacis and related forms had brains that were relatively larger than those of the creodonts, and the increase in brain size as compared with body size probably reflects an increase in intelligence.

Like many other early carnivorans, it was well suited for an arboreal climbing lifestyle with needle sharp claws, and had limbs and joints that resemble those of modern carnivorans. Miacis was probably a very agile forest dweller that preyed upon smaller animals, such as small mammals, reptiles, and birds, and might have also have eaten eggs and fruits.

Smilodon


The Smilodon are among the largest felids, the heaviest specimens of this massively built carnivore may have exceeded 400 kg (880 lb).


A Smilodon had a short tail, powerful legs, muscular neck and long canines. Despite being around the same size as a tiger or lion, Smilodon was more robustly built, comparable to a bear.
It shown to scale to demonstrate the compact muscular buildA fully-grown Smilodon weighed approximately 55 to 360 kg (120 to 790 lb), depending on species.



Limbs
Smilodon had relatively shorter and more massive limbs than other felines. It had well developed flexors and extensors in its forepaws,[citation needed] which enabled it to pull down large prey. The back limbs had powerfully built adductor muscles which might have helped the cat's stability when wrestling with prey. Its claws were retractable.



Teeth and jaws

They are the longest canines of the saber-toothed cats at about 28 cm (11 in) long in the largest species Smilodon populator. They were probably built more for stabbing than slashing. Despite being more powerfully built than other large cats, Smilodon actually had a weaker bite. Modern big cats have more pronounced zygomatic arches, while Smilodon had smaller zygomatic arches which restricted the thickness and therefore power of the temporalis muscles, and thus reduced Smilodon’s bite force. Analysis of its narrow jaws indicates that it could produce a bite only a third as strong as that of a lion.There seems to a be a general rule that the saber-toothed cats with the largest canines had proportionally weaker bites. However, analyses of canine bending strength (the ability of the canine teeth to resist bending forces without breaking) and bite forces indicate that saber-toothed cats' teeth were stronger relative to the bite force than those of modern "big cats". In addition, Smilodon could open its jaws 120 degrees, whereas the lion can only open its jaws to 65 degrees.



Smilodon probably preyed on a wide variety of large game including bison, Megatherium, Aurochs, deer, American camels, horses and . As it is known for the saber-toothed cat Homotherium, Smilodon might have killed also juvenile mastodons and mammoths.

Smilodon called sabre-toothed cat or sabre-toothed tiger, is an extinct genus of the subfamily machairodontine saber-toothed cats endemic to North America and South America living from the Early Pleistocene through Lujanian stage of the Pleistocene epoch (1.8 mya—10,000 years ago), existing for approximately 1.790 milion years.

Velociraptor



Velociraptor was a prehistoric animal measuring up to 2.07 m (6.8 ft) long, 0.5 m (1.6 ft) high at the hip, and weighing up to 15 kg (33 lb). The skull, which grew up to 25 cm (9.8 in) long, was uniquely up-curved, concave on the upper surface and convex on the lower. The jaws were lined with 26–28 widely spaced teeth on each side, each more strongly serrated on the back edge than the front—possibly an adaptation that improved its ability to catch and hold fast-moving prey.

Velociraptor, like other dromaeosaurids, had a large manus ('hand') with three strongly curved claws, which were similar in construction and flexibility to the wing bones of modern birds. The second digit was the longest of the three digits present, while the first was shortest. The structure of the carpal (wrist) bones prevented pronation of the wrist and forced the 'hands' to be held with the palmar surface facing inwards (medially), not downwards. However, whereas most theropods had feet with three digits contacting the ground, dromaeosaurids like Velociraptor walked on only their third and fourth digits. The second digit, for which Velociraptor is most famous, was highly modified and held retracted off of the ground. It bore a relatively large, sickle-shaped claw, typical of dromaeosaurid and troodontid dinosaurs. This enlarged claw, which could be over 6.5 cm (2.6 in) long around its outer edge, was most likely a predatory device used to tear into prey, possibly delivering a fatal blow.

Velociraptor (meaning 'swift seizer') is a genus of dromaeosaurid theropod dinosaur that existed approximately 75 to 71 mya (million years ago) during the later part of the Cretaceous Period. Only two species are currently recognized, although others have been assigned in the past. The type species is V. mongoliensis; fossils of this species have been discovered in both Inner and Outer Mongolia in central Asia. A second species, V. osmolskae, was named in 2008 for skull material from Inner Mongolia.

In 2007, paleontologists reported the discovery of quill knobs on a well-preserved Velociraptor mongoliensis forearm from Mongolia, confirming the presence of feathers in this species

Meganeura


Meganeura monyi was a prehistoric insect resembling and related to the present-day dragonfly of the Carboniferous period (300 million years ago), . With a wingspan of more than 75 cm (2.5 ft) wide, it was the largest known flying insect species ever to appear on Earth. (The Permian Meganeuropsis permiana is another contender). It was predatory, feeding on other insects and even small amphibians.

Controversy has prevailed as to how insects of the Carboniferous period were able to grow so large. The way oxygen is diffused through the insect's body via its tracheal breathing system puts an upper limit on body size, which prehistoric insects seem to have well exceeded. It was originally proposed (Harlé & Harlé, 1911) that Meganeura was only able to fly because the atmosphere at that time contained more oxygen than the present 20%. This theory was dismissed by fellow scientists, but has found approval more recently through further study into the relationship between gigantism and oxygen availability. If this theory is correct, these insect giants would have been perilously susceptible to falling oxygen levels and certainly could not survive in our modern atmosphere.

However, more recent research indicates that insects really do breathe, with "rapid cycles of tracheal compression and expansion". If correct, then there is no need to postulate an atmosphere with higher oxygen partial pressure.

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.

Icadyptes salasi, prehistoric penguin


Icadyptes salasi was a giant penguin species from the late Eocene period, in the tropics of South America. "Ica" for the Peruvian region where it was found, "dyptes" from the Greek word for diver, and "salasi" for Rodolfo Salas, a noted Peruvian paleontologist.

The fossilised remains of the penguin, which lived 36 million years ago, were found in the coastal desert of Peru by the team of North Carolina State University palaeontologist Dr. Julia Clarke, assistant professor of marine, earth and atmospheric sciences. Its well-preserved fossil skeleton was found on the southern coast of Peru together with an early Eocene species Perudyptes devriesi (comparable in size to the living King penguin), and the remains of three other previously undescribed penguin species, all of which seem to have preferred the tropics over colder latitudes. Perudyptes devriesi is named after the country, and Thomas DeVries, a Vashon Island High School science teacher who has long worked in Peru.

Standing 1.5 metres (5 ft) tall, the penguin was much larger than any of its modern-day cousins. It had an exceptionally long spear-like beak resembling that of a heron. The researchers who discovered the penguins believe the long, pointed beaks to be the likely ancestral shape for all penguins. Icadyptes salasi is the third largest penguin ever described.

Icadyptes salasi and Perudyptes devriesi appear to have flourished at warmer latitudes at a time when world temperatures were at their warmest over the past 65 million years. Only a few modern-day penguins, such as the African and Galapagos penguins prefer such a balmy climate.

The discovery of the fossils has caused a re-evaluation of penguin evolution and expansion. Previously, scientists believed that penguins evolved near the poles in Antarctica and New Zealand, and moved closer to the equator around 10 million years ago. Since Icadyptes salasi lived in Peru during a period of great warmth, penguins must have adapted to warm-climates around 30 million years earlier than previously believed.

Homo floresiensis, our last and small brother.


Homo floresiensis ("Flores Man"; nicknamed Hobbit) is a possible species in the genus Homo, remarkable for its small body and brain and for its survival until relatively recent times. It was named after the Indonesian island of Flores on which the remains were found.One largely complete subfossil skeleton (named LB1, because it was the first specimen found in the Liang Bua cave) and a complete jawbone from a second individual (LB2),[3] dated at 18,000 years old, were discovered in deposits in Liang Bua Cave on Flores in 2003. Parts of seven other individuals (LB3–LB9; the most complete is LB6), all diminutive, have been recovered as well as similarly small stone tools from horizons ranging from 94,000 to 13,000 years ago.

Small brains.
The type specimen for the proposed species is a fairly complete skeleton and near-complete skull proposed to be that of a 30-year-old female (LB1), nicknamed Little Lady of Flores or Flo, about 1.06 m (3 ft 6 in) in height. This short stature is also supported by the height estimates derived from the tibia of a second skeleton (LB8), on the basis of which Morwood and colleagues suggest that LB8 might have stood 1.09 m (3 ft 7 in) high. These estimates are outside the range of normal modern human height and considerably shorter than the average adult height of even the physically smallest populations of modern humans, such as the African Pygmies (< 1.5 m, or 4 ft 11 in), Twa, Semang (1.37 m, or 4 ft 6 in for adult women), or Andamanese (1.37 m, or 4 ft 6 in for adult women).



The species is thought to have survived on Flores until at least as recently as 12,000 years ago making it the longest-lasting non-modern human, surviving long past the Neanderthals (H. neanderthalensis) which became extinct about 24,000 years ago.[

The Cave lion.


The cave lion (Panthera leo spelaea) also known as the European or Eurasian cave lion, is an extinct subspecies of lion known from fossils and multiple examples of prehistoric art.The difference of size with a Bengal tiger is seen in the photo.

This subspecies was one of the largest lions. An adult male, which was found in 1985 near Siegsdorf (Germany), had a shoulder height of around 1.2 m (4 ft) and a body length of 2.1 m (7 ft) without tail. This is similar to the size of a very large modern lion. The size of this male has been exceeded by other specimens of this subspecies. Therefore this cat may have been around 5-10 % bigger than modern lions, but it didn´t reach the measures of the earlier cave lion subspecies Panthera leo fossilis or those of the huge American lion (Panthera leo atrox).[1] The cave lion is known from Paleolithic cave paintings, ivory carvings, and clay figurines. These representations indicate that cave lions had rounded, protruding ears, tufted tails, possibly faint tiger-like stripes, and that at least some had a "ruff" or primitive mane around their neck, indicating males. Other archaeological artifacts indicate that they were featured in Paleolithic religious rituals.

I put a very interesting video.

Coelacanth


Pre-dating the dinosaurs by millions of years and once thought to have gone extinct with them, 65 million years ago but....

Although now represented by only two known living species, as a group the coelacanths were once very successful with many genera and species that left an abundant fossil record from the Devonian to the end of the Cretaceous period, at which point they apparently suffered a nearly complete extinction. It is often claimed that the coelacanth has remained unchanged for millions of years, but, in fact, the living species and even genus are unknown from the fossil record. However, some of the extinct species, particularly those of the last known fossil coelacanth, the Cretaceous genus Macropoma, closely resemble the living species.[citation needed] The most likely reason for the gap is the taxon having become extinct in shallow waters. Deep-water fossils are only rarely lifted to levels where paleontologists can recover them, making most deep-water taxa disappear from the fossil record. This situation is still under investigation by scientists.


They first appeared in the fossil record in the Middle Devonian.[4] Prehistoric species of coelacanth lived in many bodies of water in Late Paleozoic and Mesozoic times.

Coelacanths, are lobe-finned fish with the pectoral and anal fins on fleshy stalks supported by bones, and the tail or caudal fin diphycercal (divided into three lobes), the middle one of which also includes a continuation of the notochord. Coelacanths have modified cosmoid scales, which are thinner than true cosmoid scales. Coelacanths also have a special electroreceptive device called a rostral organ in the front of the skull, which probably helps in prey detection. The small device also could help the balance of the fish, as echolocation could be a factor in the way this fish moves.

The average weight of the living West Indian Ocean coelacanth, Latimeria chalumnae, is 80 kg (176 lb), and they can reach up to 2 m (6.5 ft) in length. Adult females are slightly larger than males. Based on growth rings in their ear bones (otoliths), scientists infer that individual coelacanths may live as long as 80 to 100 years. Coelacanths live as deep as 700 m (2300 ft) below sea level, but are more commonly found at depths of 90 to 200 m.

Coelacanth this one near Ichthyostega ( prehistoric animals), the first fish that emerged the superfcie.

Arthropleura


Arthropleura was a 0.3–2.6 metre (1–8.5 feet) long relative of centipedes and millipedes, native to the Upper Carboniferous (340-280 million years ago) of what is now northeastern North America and Scotland. It is the largest known land invertebrate of all time, and would have had few predators.

What Arthropleura ate is a matter of debate among scientists, as none of the fossils have the mouth preserved. However, it is reasonably certain that it would have had a sharp and powerful set of jaws. Based on this assumption, it used to be thought that Arthropleura was carnivorous, but recently discovered fossils have been found with pollen in the gut,[citation needed] suggesting that the creature ate plants. It is possible that the smaller Arthropleura species were vegetarian, while the largest ones were omnivorous, using their jaws to tackle vegetation, as well as to hunt small animals and insects. It is estimated that the average Arthropleura could have eaten its way through a ton of vegetation a year.

Fossilized footprints from Arthropleura have been found in many places. These appear as long, parallel rows of small prints, which show that it moved quickly across the forest floor, swerving to avoid obstacles, such as trees and rocks. When moving at speed, its body would stretch and become longer, giving it a greater stride length and thus allowing it to move faster.

As it moved about, Arthropleura would have brushed against many different types of plant, and may have helped the forest reproduce by moving pollen or spores about the place. It is also thought that Arthropleura was capable of travelling under water, and that it may have returned to lakes and rivers in order to moult its shell. This would have made it vulnerable to attack by large fish and amphibians. On land an adult Arthropleura would have had few enemies.

Sarcosuchus imperator. The biggest crocodile of the history


When fully mature, Sarcosuchus is believed to have been as long as a city bus (11.2–12.2 meters or 37–40 ft) and weighed up to 8 tonnes (8.75 tons).[1] The largest living crocodilian, the saltwater crocodile, is less than two-thirds of that length (6.3 meters or 20.6 ft is the longest confirmed individual) and a small fraction of the weight (1,200 kg, or 1.3 tons).
The very largest Sarcosuchus is believed to have been the oldest. Osteoderm growth rings taken from an 80% grown individual (based on comparison to largest individual found) suggest that Sarcosuchus kept growing throughout its entire 50–60 year average life span (Sereno et al., 2001). Modern crocodiles grow at a rapid rate, reaching their adult size in about a decade, then growing more slowly afterwards.

Its skull alone was as big as a human adult (1.78 m, or 5 ft 10 inches). The upper jaw overlapped the lower jaw, creating an overbite. The jaws were relatively narrow (especially in juveniles). The snout comprises about 75% of the skull's length (Sereno et al., 2001).

The huge jaw contained 132 thick teeth (Larsson said they were like "railroad spikes"[citation needed]). The teeth were conical, adapted for grabbing and holding; instead of narrow, adapted for slashing (like the teeth of some land-dwelling carnivores), and more like that of true crocodilians. Sarcosuchus could probably exert a force of 80 kN (18,000 lbf) with its jaw, making it very unlikely that prey could escape.
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