Prehistoric animals

Acrocanthosaurus

2012-02-15T01:50:00.001-08:00

Without quite knowing why, Acrocanthosaurus lived to the public under the shadow of T.Rex, still a great unknown to most and undervalued its role as a hunter at the time of the Cretaceous in North America and Europe.

About the size of T.Rex, the Acrocanthosaurus was a cousin of Allosaurus and, as this was a hunter specializing in large animals, giant sauropods like Diplodocus weighing 6 or 7 times or Pleurocoelus.
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The name of this lizard Acrocanthosaurus means "thorn lizard high" and indeed, when it was discovered, even mistook him for the BIG SPINOSARUS (King of Kings). The theme of the spines always generates controversy and do not become experts agree: if they were to regulate the temperature, if it was to swim, to show your mood, or to house unions with strong muscles ... too numerous to write about this but we'll see another day.

Speaking of muscles, the Acrocanthosaurus was very muscular and strong, much more than others allosaurids. Something like an Allosaurus largest and steroids. It measured 12 meters and weighed 5.6 tons, and this made him a bit slow *. He ran and ran up to the big sauropods (which is not that they were cheetahs) long necks and hooked to these formidable pulling their strong claws and bite with all his weight down, dropping these titanic beasts.

* It was the weight and slow what they did to specialize in hunting large animals, or vice versa, hunting big beasts Acrocanthosaurus led to larger and more robust. Finally, the case is to specialize in this way produced an end. Forms were disappearing with the big sauropods, the Acrocanthosaurus were increasingly less likely to hunt and smaller dams could more easily escape them. His strength was his undoing.

Eotriceratops

2012-02-06T10:15:00.000-08:00

Recently on the blog include the legendary battle T.rex vs. Triceratops, and people keep leaving your views and comments, but what is certain is that the results would be very different and unfavorable to the Tyrannosaurus if instead of fighting against a triceratops, he should make against a Eotriceratops.

We could say that if the triceratops was a black bear, the bear was a grizzly Eotriceratops. Were indeed very similar but the Eotriceratops was larger, heavier and older. Eotriceratops means "the first with three horns on their heads." This is a triceratops that has the largest horns all have been discovered so far, something he himself would doubt the Tyrannosaurus Rex.

It is estimated that hast measured 12 meters (2 more than the Triceratops) and 15 tonnes (3 more than the T.) and had a huge head of 3 meters long ... 3 METERS!!

The Eotriceratops is older than any other group ceratopsid or Torosaurus Triceratops lived in the late Cretaceous period in what is now North America and the only known species refers to the Eotriceratops xerinsularis.

Apart from size, age and weight, has other features that distinguish it from Triceratops as one nostril much higher (for it is thought he could permacener submerged in water for long periods of time) and larger horns and near eyes.

Giraffatitan

2012-01-24T00:06:00.000-08:00

Giraffatitan, I think everyone intuit the meaning of the name: Giraffe Titan. This sauropod be at least elongated. For a long time was considered a Brachiosaurus, a prehistoric animal considering for years the largest of all terrestrial dinosaurs. In fact, Wikipedia definitions and descriptions for Giraffatitan Braquiosaurus and is the same.

The only species of the genus is called brancai Giraffatitan measured 25 meters long and 13 tall. That means you could poke your head perfectly by a fourth floor window. And its weight is estimated at 37 tonnes maximum

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Unlike other sauropods, had a constitution similar to that of current giraffes with long forelimbs and a long neck, which probably used to feed in the tops of the trees had spatulate teeth very suitable for diet . His skull has many holes, probably to reduce their weight to be a neck support 10 meters long.

The similarities with other sauropods ranging from a small brain compared to his body and he was a vegetarian who ate hundreds of pounds of conifers, ferns, horsetails and ginkgo or bennetites.

He lived in the Upper Jurassic in what is now Africa.

Triceratops vs T-rex.

2012-01-16T03:57:00.000-08:00

The legendary battle between Triceratops and T. Rex, maybe a little classic, this confrontation itself may have occurred in antiquity, in reality, and this gives a particularly morbid.

In old movies, in books for children and television shows have used this resource, this battle, as an incentive to attract attention, create suspense and tension. In some cases, the T. Rex killed the Triceratops and in other cases it was the other way around ... But in reality ... Who would win both?

This video is a movie made in 1925, was called Lost World. The Triceratops was heavy, slow and with horns that seem to exceed 50 cm. But it was not.

Triceratops.

Lengths up to 10 meters long (30 ft).
Weight: up to 12 tons (26.000 lb).
Horn of 1 meter length each. (3 ft)
Height: up to 3 meters. (9 ft)
Speed of 35 km / h

T. REX.

Lengths up to 13 meters long. (40 ft)
Weight: 10 tons. (20.000 lb)
Height: 4 meters. (12 ft)
Mouth with a strong bite.
Speed 40 km / h.

NOW LET'S SEE YOUR SKELETONS:

There are many things to consider. The powerful bite of T. rex and its poisonous saliva, and its form of attack. The speed of Triceratops that if envistiera to 35 km / h, could go through with his horn the body of T. Rex. The robustness of the body and a collar bone that covered his neck and massive head 2 meters of the Triceratops.

Silverfish, prehistoric animal still alive.

2011-12-31T04:33:00.000-08:00

All prehistoric animal lovers, we like to discover that, although not a Megalodon or a giant short-faced bear, we can delight with the observation of a tiny prehistoric animals still alive, a being that has not changed for 400 million years and for more joy, it is possible that we have at home.

These animals are called silverfish, fishmoths, carpet sharks or paramites, and are on earth so long ago that saw come and go trilobites, Dunkleosteus, at the very Hurdia Victoria, the well-known T-Rex and even our ancestors like Australopithecus.

This is a prehistoric animal in wingless insects have a long, excluding its limbs, about an inch.
Its metallic luster of the body is due to its silvery scales, which appear after the third molt.

He lives in damp and dark, most often in older buildings, or between books and papers at home.

They feed on carbohydrates such as starch or other polysaccharides. They can also digest cellulose, textiles drilling starch, sugar, hair, dandruff, dirt and mildew, books, cotton, linen, silk, including artificial silk, dead insects or even its own exuvia (shed skin) and mites.
Driven by famine, a silverfish may even indulge skin with clothing (leather) and some fabrics made with synthetic fibers. However, like many insects, is capable of interrupting their vital activity for several months without appreciable harm.

His top predator are earwigs, house centipedes and spiders

Anyway, I personally think that seeing this animal is a privilege and a gift, it is also harmless to humans (not like cockroaches), and I find it funny when turning on a light or stop run to the small, dark recesses the bathroom ... Probably been that way (hide and seek food in the dark) and have survived so many predators, so many changes in climate, so many disasters, wars and so many years. So next time you see one and go to step on it, think that this is a prehistoric animal.

Daspletosaurus

2011-12-21T03:54:00.000-08:00

THE TERRIBLE carnivorous reptiles. That was the name we put this dinosaur, Daspletosaurus. It was another prehistoric animal Tyranosaurido fierce-looking and although a little smaller than its cousin the famous Tyranosaurio. Even being smaller, this dinosaur was a predator that stood at the top of the food chain and devouring other animals such as large or some Ceratopsidae hadrosaurids (horned Triceratops) of several tons.

Possibly, his name is due to the impression that was taxed in the retina of the paleontologists who discovered it: a huge head of 1 meter with 72 serrated teeth, long and sharp with heterodoncia (specialized teeth). Measuring up to 9 meters long and it is estimated that almost could have reached the 4,000 kg.

A feature to highlight in this prehistoric predator was his strong neck and a strong legs (compared with other similar sized tyranosauridos.

The strong hind legs brought him agility and speed in racing, and a starting power and strength to pursue valuable prey. It was really a terrible carnivore and fast.

On the strength of his neck, holding a skull strong armed indeed, its function was to hold its prey. Since its forelegs were minimal and not very useful, Daspletosaurus used their strong teeth to catch and mortally wound its prey. Grab their prey with a bite bowed numerous sharp teeth and retained and the onslaught endured and the struggles of its prey with its powerful neck.

The Daspletosaurus lived in North America in the Cretaceous period about 75 million years.

In the video below looks like a group of successful practice Daspletosaurus a hunt. (Up to 4.40 min)

Quetzalcoatlus.

2011-12-07T02:33:00.000-08:00

One of the first animals that we put in the blog was the big Azhdarchidae. Huge pterosaur (flying reptiles) with a wingspan of 10 meters. Well, now the largest pterosaur know all ... indeed is considered the largest flying animal of history: the Quetzalcoatlus.

The Quetzalcoatlus was by far the largest flying animal. For example, a current condor reaches 3.3 meters (11 ft) , 3.6 meters (12 ft) of an albatross, a magnificiens Argentinavis reached the 8 meters (26 ft) wingspan, large Azhdarchidae reached the 10 meters (33 ft) ... but the Quetzalcoatlus reached 15 meters (48 ft) . And while most current research suggests that reached 12 meters, still the largest flying animal ever.

The most representative species of this genus is the northropi Quetzalcoatlus, a pterosaur, with a similar appearance to other pterosaurs had a long beak, sharp and toothless. With a small head and a ridge height of almost 5 meters (16 ft) when placed standing, weighing 200 kg (450 lb) . To think that 200 kg (450 lb) is a lot for a flying animal, for example, weighs 12 kg (25 lb) condor, so some experts believe that weighed much less ... about 80 kg.

It lived in the Upper Cretaceous (Maastrichtian ago by 68-65.5 million years ago) in North America.

Carcharodontosaurus

2011-11-16T03:19:00.000-08:00

The word "Megalodon" means big tooth and its scientific name is Carcharodon megalodon tooth mean much sharp (or sharp). Knowing this, it is easy to know why the name of this prehistoric animal: the Carcharodontosaurus which means lizard with sharp teeth.

An animal with this name can only be a hunter, a predator, why would an herbivore have fangs ...?

Carcharodontosaurus was not a second predator. In fact, the family that was part (Carcharodontosauridae) appeared some of the largest known land predators, such as Giganotosaurus, the Mapusaurus and tiranotitán. All these strong predatory theropods that reigned over other animals in their geographic areas and their corresponding time.

His appearance was fierce, and tanmaño negligible. I could measure up to 12 meters long, weigh up to 4 tons, and 4 meters high. To give you an idea, the T. Rex measured 14 meters long and of course heavier, but has anyone ever think that it was a lizard Carcharodontosaurus hardly any importance in the world of prehistoric predators. Carcharodontosaurus also had one of the largest skulls of carnivorous dinosaurs. And the larger relative to its size. A skull of 1.5 meters, about 10 cm less than the Giganotosaurus, which measured up to 18 meters long. Besides his jaw pressure is estimated at 3.5 tonnes and full of jagged teeth like those of sharks could tear flesh but was protected with scales, so their prey died bled also had sharp claws his hands as hooks butcher to support a victim while its jaws tore.

Other data supporting this was a good predator:

The carcarodontosaurios had a two dimensional view, as any good hunter. They had like a long, muscular legs, and trace fossils indicate that they could run up to 30 km / h, but now this is controversial.

Finally, we should not make myths of T. Rex, Spinosaurus, Allosaurus or Giganotosaurus, because after all other dinosaurs were able to shadow them, as the Carcharodontosaurus.

Carcharodontosaurus lived in Africa during the Cretaceous.

Hainosaurus

2011-11-10T23:18:00.000-08:00

You have certainly heard of Mosasaurus, the great predator of the Cretaceous, a fearsome marine hunter was afraid of other creatures of the sea but ... and Hainosaurus? While not believe it, the Hainosaurus belonged to the same family as the Mosasaurus, Mosasauridae the family.

He was also a marine reptile, an apex predator that lived with her relative Mosasaurus.

Hainosaurus dimensions have been debated: Some experts believe that reached 17 m (57 ft) and 13 m (42 ft) change others, but the vast majority agrees to an average size 15 meters (50ft).

This hunter's skull measuring 1.5 meters (5 ft) long. And in his jaws were more than 60 teeth are sharp and hard. Among their prey were fish, turtles, marine reptiles and even smaller sharks.

The hainosaurus had an elongated body that was perfectly adapted to the water to achieve greater agility and speed. They had fins on the sides and curved tail with fins to swim very fast, to reach out and catch their prey without that it can do almost anything.

This prehistoric animal was specially adapted to be in the water, and some of the questions that have their fossils are related to how and where breeding and giving birth to their young, uncertain whether it was viviparous, oviparous or ovoviviparous.

Although little is known of this marine reptile, I hope you discover more about the wonderful Hainosaurus.

Moeritherium, the ancestor of the elephant.

2011-10-28T00:19:00.000-07:00

40 million years ago appeared on Earth the first elephants, rather the ancestors of the modern elephant. One of the ancestors called Moeritherium, which means "Moeris beast," which is an ancient lake in Egypt. Not only was the ancestor of modern elephants, was also the forerunner of the mammoth and mastodon, all Proboscidea (order of placental mammals). In addition it is also thought to be related to the manatee or sea cow or also known as Sirens.

The Moeritherium was small compared with an African elephant, the size of a big pig, a vegetarian-bodied, plump and heavy. He had thick legs, long, thin skull. Is believed to have had a rudimentary horn was somewhat flexible like a tapir or the Macrauchenia current. Instead their eyes and ears of the hippopotamus seemed to be placed in the top of the head perhaps for the amount of time remaining in the water of swamps and rivers. It is thought that the same ecological niche occupied in the hippo. But with them and speaking in evolutionary terms, they have nothing to do.

The protofeather or Dinofuzz.,

2011-10-13T03:51:00.000-07:00

The protofeathers (or Dinofuzz) ... the great mystery of reptilian scales transition feathers.

What are protofeathers?

The protofeathers are structures shaped keratin hair or bristle and are considered the precursors of feathers.

When did?

Much of all this passionate debate is the date of appearance of the feathers, protofeathers. It is interesting that the oldest fossil
protofeathers are later than the earliest known bird. It makes no sense unless the protofeathers or dinofuzz appeared much earlier (in the Middle Triassic) and therefore would all structures originally present in dinosaurs and their immediate ancestors. Impressions of skin devoid of feathers or protofeathers known (Anatosaurus, Carnotaurus, Tyrannosaurus, etc..) Could be due to a subsequent loss of the outer coating due to the large body mass of these animals (the same reason that the rhinos and elephants have virtually no hair). But this need not be. Anyway ... although I am inclined to this theory, it really is just a theory.

How are the protofeathers?

According to the current expliación: One of reptilian scales ... This is the first spine, then becomes hollow and extends, as it grows, it follows from the skin and forms a cluster of hairs called beards or barbules.

In this video you can see the process of formation of protofeathers.

Why are important protofeathers?

For as we said, are the precursors of feathers. The appearance of the feathers is one of the most controversial issues can be found by paleontologists.

Apart from that it is not clear when they appeared, the experts, agree with in the end, why they left feathers: feathers but now used to fly (the most important feature) is considered to formation of these was a simple cold protection system. A coat of hollow scales isolated from the ravages of time.

Why were transformed into feathers?

Protofeathers are known to be used to maintain body heat and cover the body from the cold. And the fossils discovered (or most) protofeathers concentrations were located on the tail and arms. This allowed them to cover her at night and cover the cold while the temperature down ...

It is no coincidence that birds have feathers on the wings larger (called T-shirts or remiges) and tail (tail feathers or rectrices). They were the first to develop, were the first to appear were also exercising more air resistance. An important feature for small arboreal animals, leaping from branch to branch or thieves fast and small eggs.

What were the first to have protofeathers?

There are several examples of theropods (a group of two-legged carnivores, which is the T. Rex or Velociraptor). Some are: Dilong paradoxus, Sinosauropteryx, Shuvuuia, Beipiaosaurus, Sinornithosaurus, etc ...

But not only are the developers of theropods
Dinofuzz protofeathers or, for example there is the Tianyulong, a small herbivore that is casting doubt on its position in the evolutionary tree and it was discovered 2 years ago.

Finally, there are still many questions to solve, finding fossils and discovering new species. A truly exciting topic of prehistoric life on our planet.

Saurophaganax, theeater of saurians.

2011-09-26T13:01:00.000-07:00

Saurophaganax, theeater of saurians is a genus represented by a single species of theropod dinosaur alosáurido: Saurophaganax maximus.

This was a predator who was at the top of the food chain of the time. A hunter considered the gender of the Allosaurus, which rivaled the east by the Jurassic reservoirs superior.De titanic fact, Saurophaganax maximus, was greater than any Allosaurus... as a Zhuchengtyrannus. Could grow to 11 meters long (36 ft), 3.5 tons, and nearly 4 meters (17 ft) high ... But some paleontologists experts who have researched their fossils suggest that it could reach up to 15 meters (50 ft)long and nearly 6 tons (as T. Rex) y. .. apart from these data that can help us imagine a similar beast, S. maximus shared a characteristic of other species of Allosaurus: speed. Could grow to more than 10 km / h; nothing compared to a Formula One car but far more titanic than animals that were part of their diet as the Apatosaurus.

If it was a Allosurus or not is not known, but is increasingly more confident that it is not, what we do know the Saurophaganax maximus is: if it looked like the Allosaurus, the bite would be so terrible as these predators ... not good .... even more powerful and effective because it is a large species 3 meters (12 ft) and two tons heavier. We could say that if the Allosaurus was a bull shark, S. maximus would be a great white shark.

The main feature is its maximus Saurophaganax horizontal plate at the base of the dorsal neural spine, this gives a look similar to the typical fantastic dragons have a series of chevrons along the body.

Madtsoia bai

2011-09-13T04:34:00.000-07:00

Imagine dragging 3.000 lb of muscle stealthily lurking in the swamps and the darkness of the jungle. A being with a cold stare that shakes because it reflects the very death. I'm talking about THE WORLD'S LARGEST SNAKE AND THE STORY ... And prehistory.

The Madtsoia bai or as it is commonly known "the grandmother of Cow Canyon" is a species of the genus madtsoia and is possibly the largest snake ever found and even bigger than Titanoboa.

In 1931, evolutionary paleontologist George Gaylord Simpson found the fossilized skeleton of a snake in the town of Cow Canyon, located in the southeast of the province of Chubut (Argentina).
This prehistoric animal was a snake constrictor, meaning they hunted their prey by strangulation, not poison, squeezing and squeezing its prey more and more each time the prey exhales the snake tightened until the victim can not recover this vital air and dies by suffocation.

The estimated sizes for this giant snake is between 50 and 65 feets, diameter 2 feets and weighing up to 1.5 tons. For example, the current Anaconda fails, almost never, 8 meters, 35 cm in diameter and 450 lb ... and is the largest in the world.

On the other hand, imagine the animals would be able to swallow this thing of prehistory. If you lived in Argentina Patagonia 90 million years ago and has been extinct for 2 (or so they say), bony part of the Cretaceous and Pleistocene, could engulf prey as Abelisaurus terrible, a great Toxodon or even one of the first cats that Smilodon drinking approached carelessly.

15 m years ago began a process of cooling and desertification of Patagonia, which was gradually shaping the current face of the region as well as climatic and environmental conditions that we know at present.

The giant snakes do not support these changes and became extinct, or in some cases, retreated northward, giving rise to the current species of large snakes.

Allosaurus fragilis.

2011-09-01T23:29:00.000-07:00

When I wrote the post of Allosaurus Europeaus, also promised to write about the Allosaurus fragilis, the best-known species whose fossilized bones have more information to the expert paleontologists.

But not only important for the amount of fossil fuels. Anyone who has heard or knows anything about the dinosaur Allosaurus know that this was a T. Rex of his time. It was a prehistoric monster that was in the top of the food chain, a predator with a bite capable of prey animals as large as Stegosaurus and Diplodocus.

Fortunately for the Allosaurus did not have to deal with T.rex (who lived 80 million years later), the Spinosaurus (30 million years later) or Giganotosaurus (60 million years ago). Possibly the only species of dinosaur that could stand up was Saurophaganax that like Allosaurus lived for about 150 million years in the late Jurassic.

Their physical characteristics are:

Length: Nearly 30 feets long.
Height: 13 feets.
Weight: 6000 lb.

(T.rex- 43 for long., 18 tall and nearly 13.000 lb)

Although smaller than T. rex, Allosaurus's body was much the same way, the only notable difference was that his front arms were compared with the body, stronger and longer.

Another feature is that the Allosaurus (some experts believe) reached high speeds ... of course for these sizes of dinosaurs. Reached speeds of up to 6,2 mill / h and this speed could reach any of stalking and its victims.

Once the victim came to them with a bite attack stubborn 70-curved teeth inward dams prevented their escape, lest they (the prisoners) do without the piece of meat that was trapped in its jaws Allosaurus.

Rhamphosuchus

2011-08-22T07:48:00.000-07:00

For months we talk about one of the largest crocodiles in the history and prehistory together. We refer to Deinosuchus, a crocodile measuring between 12 (40 ft) and 15 meters long (50 ft), which lived in the Cretaceous dinosaurs that hunted among other prey.

The crocodile you today is possibly the largest crocodile ever. A crocodile with a size that could grow to 18 meters(58 ft). (Opinions vary on the size, some experts say that half to 18 meters and 15 ... in any case would be one of the largest crocodiles.) Called Rhamphosuchus and like other crocodiles, current and extinct expected lurking in the river banks until prey came to drink and then ... zas!. A deadly bite, a fatal bite when caught their prey would not let go until he stopped breathing.

Among their prey might have found a Platybelodon, an ancestor of the elephant, and even a hominid Anisodon ancestor of ours as Gigantopithecus, the largest single story.

A Platybelodon, an ancestor of the elephant, 2 meters (7 ft) high and over 2 tons that even with its enormous weight and strength, could do nothing against this 10-ton crocodile, a mouth of almost 2 meters, 18 meters and one of the Bites more pressure throughout the animal kingdom (almost nothing).

Come on, all animals are herbivores or carnivores, prey or hunter, trembling at the close presence of this great monster, this large predator.

A bit of prehistory.

2011-08-07T07:43:00.000-07:00

Everyone knows the prehistory of the mind in which the dinosaurs disappeared about 65 million years. But few people know another story even more fascinating and more importance for what is life on land, but especially and more specifically, to us humans. It was not an isolated event but a chain of events, a struggle between forces of evolution among prehistoric creatures that ended with one victor, our ancestor ......... The story begins:

500 million years ago.

So far life in the prehistoric seas, oceans before the beginning of the Cambrian period,
consisted of single-celled or multicellular creatures (many
cells, but all the same) soft body, which they obtained their food by filtering the water around them, or feeding on bacterial mats (dense colonies of bacteria) on the ocean floor.

I will not go into details but then gave a very important place, which is known as the Cambrian Explosion, say it is from this date (500 thousand years) when the three-edged mother will result in all other species we know and that interaction

between them, set up, the situation now is the arthropods, molluscs and vertebrates (the group we belong to).

Well, at that time, life beyond the seas was unknown, and the seas and oceans were then inhabited by beings of strange shapes as the famous trilobites and other less friendly as Anomalocaris (left) or Hurdia Victoria (the latter were the top predators of the time). These three species were among the arthropods. The dominant and most numerous group that reigned on molluscs (its variety was insignificant) and vertebrates.

In fact, the Cambrian vertebrates were a small and unimportant. For example, while Victoria Hurdia reach 50 cm or up to one meter Anomalocaris, the

representative of the larger vertebrates that was Pikaia (pictured right) did not exceed 5 cm
length. Come on, that our ancestor was a true miniature land of giants.

The pikaia our ancestor, was long, small, light having a backbone instead of shell but it was also the major arthropod prey. He devoted himself to hide in the care of arthropods and eat the waste and the remains of prey left by large predators battleships were mainly scavengers.

Nothing seemed likely to change, the arthropods dominate the land and seas over the millennia, eating and leaving decimated vertebrates, thus reducing the possibility of not only our species but also birds, dinosaurs, fish and other mammals, may appear in the future. But conditions changed.

450 million years ago.

In the late Ordovician period (the next to the Cambrian period) was the second largest extinction of life on Earth history, eliminating 85% of the species.

A global ice age that froze oceans and seas

covered them with a blanket of 800 meters of ice and snow had catastrophic consequences for the life of this era. The lack of light and the intense cold was killing larger species and more specialized, bone arthropods. This led to the other two groups (vertebrates and molluscs) may develop: vertebrates evolved and appeared larger scavengers such as conodont (about 10 cm, right image). But they were vertebrates which rose to the position of the dominant group, but molluscs. The supremacy of vertebrates was cut again, but in this case by the large mollusks.

Now the predators were large molluscs such as Ortocono (left)

and Nautiloidea. And they dominated the other groups until they took another step, one giant leap in the way of the evolution of arthropods came ashore.

On land they had no predators, and eventually took the opportunity to grow and multiply. There were big and strong and the seas again to reconquer. And they succeeded. Arthropods were Jaekelopterus rhenaniae most important ancestors of scorpions and giant like Pulmonoscorpius.

Over time, the move gave them the advantage on mollusks to arthropods and vertebrates (leaving ground) would also be a fatal mistake that would destroy them.

375 million years ago.

Gradually, over the millennia, vertebrates were going to land, a land that was populated with a number of plants that helps to oxygenate the atmosphere and produced the right conditions for our ancestors to develop.

Shellfish centuries ago who had returned to background. In contrast, on land, vertebrates were developed only arthropods and began to exceed the size, strength or agility of the arthropods. The last battle was about to begin.

On the one hand were the arthropods were strong but had a weakness: its outer armor. They had to grow as the animal grew. If the animal was too big armor, and thus increasing the animal's weight. Could weigh as much that came a moment that was counterproductive in an evolutionary sense. At best, could reach a size of 3 meters.

On the other side were the vertebrate ancestors. Animals that could grow larger without becoming too heavy to be sustained. Vertebrates, thanks to its design, its backbone, they could better adapt, develop better, evolve ... and all this without becoming heavy tanks.

250 million years ago.

The reign of the arthropods are gone forever. And with this came the dinosaurs, birds, fish ... y.

.. us HUMANS.

Pliosaurus Vs Plesiosaurus.

2011-07-27T01:10:00.000-07:00

Pliosaurus and Plesiosaurus are two distinct genera of the same family or order of marine reptiles that lived in prehistoric times. Now there are few giant marine reptiles, arguably the most important the marine crocodile with more than 6 feet long, but that was nothing compared with the members of these two genres that were true sea monsters. Here are some.

Pliosaurus.

They were usually large predators with large jaws and well armed, short necks. Some examples are:

Kronosaurus A marine reptile which, like other Pliosaurus, had short necks but strong. Their jaws measured 2.5 meters long fang-filled and the length of his body could be up to 12 feet and weigh 15 tons. Some call it the Rex Marine.

Liopleurodon was another Pliosaurus but with their own families, the Liopleurodon was a great swimmer, a lively marine predator,

with a shape similar to but even larger Kronosaurus. Grow to 27 meters and weigh 150 tons, was able to pursue quickly and for long periods at their prey. With jaws 3 meters long and with teeth to tear to twice as long as those of a Tyrannosaurus Rex. (30 cm long)

PREDATOR X. A curious name for

an animal surprising. It is believed that X was a Liopleurodon Predator, a large skull and huge jaws, its dimensions were similar, maybe a little smaller: a 3-meter jaw full of teeth over 30 cm long and it is

believed, was an animal that had more bite force among all known.

Plesiosaurus.

Large predator fish from four large fins and long necks characteristic of animal facilitated its kind that raises its head to breathe. The best known are:

Elasmosaurus. About 15 meters long, which were 8 meters long neck and the rest is for your body. With a weight of 9 tons, was a heavyweight of the oceans of the Cretaceous. And although it was stylized and rather graceful, was a super-predator of the time. Although he was no match with any of the three Pliosaurus we've seen (like the Predator X Kronosaurus or who were his rivals and could live at the time)

NOTHOSAURUS. Another known Plesiosaurus, possibly one of the first of its kind. Not exactly a Plesiosaurus, but was (or any of its branch) who gave birth to this genre. It was "little" about 4 meters long and less than a ton. With strong long teeth that bite and to catch fish served with a quick bite.

CRYPTOCLIDUS. Possibly the second most popular after Elasmosaurus Plesiosaurus. Was over 8 meters long and weighed 8 tons. His neck, long as all Plesiosaurus was more robust than others, however its elasticity was lower. This being a predator rather Bland. Hunted large prey and not be satisfied with simple and small dams. However, it was an animal whose size had very few enemies.

Now, after the abstract, let's see some videos:

The Platybelodon, an ancestor of the elephant.

2011-07-19T23:40:00.000-07:00

The Platybelodon was one of the ancestors that gave rise to modern elephants, though not unique, but so is the strangest appearance.

The Platybelodon was herbivorous, and like the current hippos, spent much time in the swamp water where they feed on aquatic plants. One of the most curious features of this animal from the Miocene was his two bottom teeth shovel-shaped. Two teeth were disproportionately long and wide, however, the teeth (protruding into the mammoths, mastodons and elephants) were small and insignificant.

Another use of these teeth is lower than was to grab the trunk and branches, serrated rubbing against the lower teeth to cut the tree.

Robust and heavy as a small elephant, it can weigh over a ton and a half and could grow to 2 meters high. As I said before, lived during the Miocene, from 15-4 million years, and lived in Africa, Europe, Asia and North America. Although it thrived during his time, did not survive beyond the Miocene. Although no one knows exactly why he died.
In any case, this curious animal, this ancestor of the elephant, the mastodon or mammoth, is an example of the diversity and richness of fauna in prehistoric times.

Brontornis burmeisteri

2011-07-03T23:03:00.000-07:00

A fearsome carnivorous birds and greatest of all time was the Brontornis burmeisteri. A flightless bird belonging to the subfamily Brontornithinae, which rivals the size of titanium-prehistoric other birds such as the family of Phorusrhacidae (known as "Terror Bird") or other more current and Dromornis (known as the "elephant bird").

The Brontornis burmeisteri was first introduced in the subfamily of "Terror Bird" and it is because their physical characteristics were similar for its large size and predatory lifestyle, and more specifically introduced in the subfamily Brontornithinae that contained very large and stout forms.

Had a height of almost 3 meters and its weight could reach 500 kg. He had some strong legs, able to tear the skins of their prey with a single blow. To get an idea: we can look at the Cassowary bird-like prehistoric currently living in Australia and New Guinea and is able to kill people with their claws. It measures half a burmeisteri Brontornis and herbivore.
The prehistoric bird lived in what is now called the Patagonia (South America). Due to the volume, is likely to have a lifestyle between an ambush predator and prey actively chasing, jumping on her and shot down by the strike force after a short chase.
Was the dominant carnivore during the Miocene Patagonia, being able to kill even large animals like elephants and the predator Thylacosmilus Astrapotherium (a saber-toothed marsupial).

Simply fascinating.

Nephila Jurassica

2011-06-20T01:31:00.000-07:00

What is the largest known spider in prehistory? I guess those with arachnophobia do not want to know. But for everyone else, this question is no longer, at least, interesting to know.

Currently, the spider named Goliath is larger and heavier there. You can reach 30 cm in length with legs extended, although poisonous, is not fatal.

The fossil ever found largest spider is the Nephila Jurassica. A spider bigger than Goliath. Each leg was 15 cm and its body (the females who were older) had a thickness of up to 12 cm. We extended that could reach 42 cm easily.

Nephila Another curiosity is that the oldest fossil spider found. And it was in April 2011 when they discovered their fossils in what is now China.

Another curiosity of this spider is that their fossils belong to the Jurassic and the Carboniferous (when there were large insects that increased much in size by the lack of predators and the high concentration of oxygen in the atmosphere). But hey, that does not mean they do not exist. In fact we think that existed when the land was a continent, Pangea, 1000 million years ago.

Finally, little is known of Jurassica Nephila, sure we'll learn more over time.

Baryonyx "heavy claw. "

2011-05-27T02:12:00.000-07:00

As put in the post title, Baryonyx means "heavy claw. " "Heavy Claw"because its huge claws slashed to 35 cm long (1 ft) perforated skin of other dinosaurs, their prey, unable to prevent the tear resist them. "Heavy Claw"because its forelimbs were strong with powerful muscles used both to support and move to attack their prey.

Depending on the shape of the hip, suggests that to move at high speed using all four legs, but at rest or attack was on a biped.

The long neck was very inflexible and had no S-shape of many other theropods. The skull was inserted at an acute angle and not straight, as is common in similar dinosaurs. The large jaws were uniquely crocodilian in appearance and had 96 teeth, double most of his relatives. 64 of these teeth were located in the lower jaw and 32, longer at the top. It is possible that the nose has a small ridge. The upper jaw had an acute angle near the snout, a feature seen in crocodiles that helps prevent the prey from escaping.

The Baryonyx was about 9 (30 ft) meters long and weighed nearly two tons and 4 meters (12 fts) high. FIRST This dinosaur was a predator, although its features is thought that large numbers of prey were aquatic animals. The teeth of his jaw that prevented their prey bite out of her with his huge claws and drew water for prey.

The Baryonyx lived in what is now Europe 125 million years ago (Cretaceous).

BY THE WAY IT IS OF THE SAME FAMILY Spinosaurus. (Spinosauridae)

Image of http://www.foro3d.com/f27/baryonyx-pescando-64603.html

Kronosaurus.

2011-05-12T07:26:00.000-07:00

Inside family of animals Pliosauridae are as terrible as the Liopleurodon or Predator X, marine predators of enormous size with huge heads and huge teeth. Within this group, the third in size (not so small) was the Kronosaurus. Its name means "the lizard of Cronos" (Cronos in Greek mythology was the leader of the Titans).

The Kronosaurus came to measure up to 12 meters (40 feets) and weigh 15 tons. To give you an idea: a whale comes as much up to 9 meters long (30 feets) and at most 6 tons. Another comparison: the skull of a whale "only" is 1.5 meters (5 feets), in contrast, had a skull Kronosaurus 2.7 meters (10 feets) ... Few carnivores were these dimensions and these weapons so deadly.The Kronosaurus had long, sharp teeth, not serrated. Peculiar and distinctive teeth that have made it easier to differentiate between fossils and they are of a Liopleurodon or Kronosaurus.
The Kronosaurus was probably the apex predator of the time. No other animal could stand against him and had to flee if they did not become their prey. Have even found fossilized skeletons of the long Elasmosaurus, a predator of 14 meters.
Fortunately for the Kronosaurus, during the time he lived, Lower Cretaceous, there were his cousins Liopleurodon or Predator X, who disappeared for more than 50 million years before the appearance of Kronosaurus.
Finally, the Kronosaurus, lived in the prehistoric waters which now include Australia and South America.

Megistotherium

2011-05-02T09:14:00.000-07:00

The Andrewsarchus or Androsarcus, was considered the largest carnivorous mammal history, but that position was occupied not alone. Along with this there is another giant carnivorous mammal, called Megistotherium (and some experts say it could even be larger than the Andrewsarchus). The Megistotherium was a terrible predator, a predator who struck fear Miocene to the titanic mastodons (found fossilized bones of mastodons with Megistotherium marks indicating that hunting for food).
The Megistotherium belonged to the family of Hyaenodontidae, a family of large predators, strong, aggressive and courageous. Predators that were in the top of the food chain before the mega saber-toothed cats like, or the greatest, the cave lion.
The Megistotherium lived in what is now Europe, Africa and Asia. As large as the current bison, weigh up to 1500 kg (3300 lb) and a height to the shoulders of more than 1.5 meters long and 3.5 (a white bear almost never reaches 1000 kg (2200 lb) and is 2.5 meters long). The dimensions of the skull were Megistotherium up to 1 meter long (similar to Androsarcus) and his jaw with a force of enormous pressure, harbored very powerful teeth can grind the hardest parts of prey such as bones or hooves. Do not forget that the family is synonymous Hyaenodontidae hyena's tooth, and these (the hyenas) are known for the strength of their jaws and teeth trituratodo. To get an idea, your name, Megistotherium, means "the biggest beast crushed bones."

Zhuchengtyrannus.

2011-04-03T01:18:00.000-07:00

That discovery! The cousin of the Tyrannosaurus Rex. A new tyrant among the dinosaurs of the Late Cretaceous (between 99 and 65 million years ago), a great beast, a new predator found, their fossils, currently Zhucheng in Shandong Province (east China). Therefore, it has been dubbed the Zhucheng Tyrant.

Tyrant could describe as a Tyrannosaurus Rex Zhucheng but a little smaller. For example:

The Tyrannosaurus was approximately 14 m in length, of Zhuncheng reached 11 meters. Negligible size, we ... that if you look down the street ... .... .... you make it over (not I think of another expression).

A little lower and also weighing less. T. Rex weighed about 6 tons, however, the Zhucheng weighed 4 tons.

Still, the new finding corresponds to a terrible carnivore with a powerful jaw, small arms like the Tyrannosaurus Rex. Possibly, like the T. Rex, Zhucheng could have been predator but a scavenger.

Anyway, so far are some fossils have been found from this dinosaur, a few vertebrae and mandible (with teeth certainly unique, larger in proportion to his jaw in the T. Rex). See if you still discovering more fossils and they can illustrate.

Argentinosaurus.

2011-03-23T02:30:00.000-07:00

I have wanted to talk about the Argentinosaurus, a huge dinosaur, we talked about it when I wrote about other terrestrial animals such as colossal Amphicoelias fragillimus or Diplodocus. Well ... Argentinosaurus was THE LARGEST LAND ANIMAL STORY (after Argentinosaurus, although this is of doubtful existence). And not only was the second largest, was also a heavyweight. Let's see some data.

* The Diplodocus measuring 35 meters and 80 tons. (green)

* The Argentinosaurus 40 meters and 100 tons. (gray)

* The fragillimus Amphicoelias was up to over 45 meters and 120 tons. (red)

As shown in the video, was a huge animal, weighed, a giant terrestrial. Grew to be 20 meters high, as a 6-storey building. When stepped on, the ground rumbled like an earthquake, and a frightened herd (if there is any animal that could do that) made the ground tremble.

This herbivore ate Cretaceous pines in what is now South America. Hence its name: Argentina (Argentina) and saurus (lizard).

Anisodon. Chalicotheriidae.

2011-03-15T02:38:00.000-07:00

The Anisodon belongs to the family or Calicoterios Calicotéridos (Chalicotheriidae). It is very curious, strange to our eyes. The truth is that we look like a cross between two animals: a horse and a gorilla (for example).

In fact, although the head and body were similar to those of the horse, walking in a more upright, similar the gorilla and not as current horses. Its front legs were long and short the back, so I walked in a manner more similar to gorillas than horses. But the resemblance to the gorillas are not only the way to go, also had no claws, but claws and knuckles rested on them. In the front legs were huge, curved claws, probably used to get the leaves on the trees as they were browsing on forest and verifications may be standing on its hind legs to reach higher branches. They could not run, and it was his claws and great strength and size that can be served as a defense against predators. On its hind legs could reach more than 4 meters high.

Some cryptozoologists have hypothesised that (the supposedly carnivorous) cryptid from Africa, the Nandi Bear, could be a chalicothere.

Appeared in the Miocene and as mentioned in Wiki, possibly survived until "a few years. "

Bison latifrons

2011-03-03T03:57:00.000-08:00

On with huge animals. You've ever been near a bison? Are enormous strengths. His big head and his eyes intimidates let you know that if lash, nothing could be done. The current bison weigh no more than 1,500 kg have a maximum height of 1.80 and about 3 feet long.

But there was an even greater bison, Bison latifrons was called. A huge beast, 2.5 meters high and 5 meters long. And a mass of 2,000 kg and full of strong muscles in the neck that held a big head, only his head was heavier than any of us. Not only that, his head held an antler of more than 2.5 meters long, exceeded in size by counting animals, such as Megaloceros giganteus.

Currently, the family of the largest bovine animal is Bos gaurus that can measure up to 4.60m long and 2.20m high.

The Bison latifrons get other names like giant bison or bison ice age, and who lived during the Pleistocene in North America.

Image Shayne's Photo Journal.

Goliath or Homo heidelbergensis

2011-02-25T02:30:00.000-08:00

About half a million years began to take shape morphological traits in hundreds of thousands of years gave rise to Neanderthals. The Pre-Neanderthal or Homo heidelbergensis showed increasing physical bulk, expressed in increasing height, from 1.75 to 1.80 meters (5,9 ft) and about 100 kilograms (half male, 220 lb). The jaws also possessed a

great power and strength because of stress to which they were subjected.

All these fossils reveal a hominid skull with a "bloated" than that of any H. erectus / H. ergaster, but still has superciliary arches. The back of the skull is more rounded than in H. erectus / H. ergaster, and the cheeks are inflated, as in the Neanderthals, though the face is flatter. His ability neurocraneal not far from modern man, was about the 1,350 cm ³. Another similarity with Homo sapiens was his vocal apparatus. This led to think that language, understood in a way perhaps different to the current, already present in these groups.

After Gigantopithecus, Goliath is the largest of hominids.

The tools associated with the fossils consist mostly of "stone cutting" and some tools and tips flakes and scrapers of wood, bone and horn, being the pioneers of this technique. Inside we find the double-sided technology, also called a hatchet, is large and is carved on both sides. Its usefulness is very diverse. According to analysis of other stones show their use to tan leather or wood working, and 400,000 years ago using crude wooden spears. It is also likely that at this time the fire was widely used and gradually, as there is evidence of fires.

Gigantopithecus, the biggest monkey story.

2011-02-16T02:04:00.000-08:00

From 1 million years ago until 300,000 years ago (just a little more), there was the bigfoot or the yeti. A real yeti no kidding. Gigantopithecus was called, and was a relative of our species. It was the largest primate WHO LIVED ON EARTH. He lived in modern-day China, India and Vietnam and may have coexisted with Homo erectus in Southeast Asia. Huge, strong, more than our nearest ancestor "Goliath" or Homo heidelbergensis, a vegetarian titan closer to orangutans.

Let's see some features.

WEIGHT:

An orangutan can weigh up to 120 kg (264.554 lb), and a gorilla (well formed) to 200 (440.924 lb). Gigantopithecus, which exceeded, it almost doubled and tripled. Weigh up to 500 kg (1102.311 lb). Like a bull. Come on, almost 3 times the weight of a giant ape.

HEIGHT:

An orangutan rarely exceed 1.75 meters in height and a gorilla more or less the same. But is that we are seeing great ape reaches 3 feet high. Much more than basketball players higher. (the highest with 2.47 (8 ft) Sultan Kosen weighed 150 kg and had a condition called gigantism)

Other things, according to Wikipedia: It was probably herbivorous quadruped, with a diet similar to the giant panda based on bamboo, possibly supplemented with seasonal fruits.

Among the causes of extinction: competition with giant pandas in the bamboo forests and the arrival of humans, which may also have eaten bamboo and used them to make tools, might have made survival difficult for Gigantopitehcus.

Indeed, some have postulated that cryptozoologists legendary beings across geographies known as Yeti or Bigfoot could be Gigantopithecus varieties that have survived to the present. mmmmmm I do not know

Bonnerichthys gladius.

2011-02-09T01:17:00.000-08:00

The abundance of the seas can feed giants as blue whales, the largest animal ever. An animal prey are among the smallest in the world. Enter in their mouths a lot of water full of plankton is trapped in the baleen to filter the water.

But this way of eating is not unique in today's whales. There were huge fish that fed the same way. For example Bonnerichthys gladius. A fish of about 8 feet long that lived in the oceans for over 100 m illion years in what is part of the Cretaceous and Jurassic

The gladius Bonnerichthys had a disproportionate head, big eyes, toothless mouth, butextremely elongated jaws. He is credited with the first animal that was fed by filtration.

By the way, do not remember the basking shark??

Shonisaurus sikkanniensis.

2011-01-26T03:21:00.000-08:00

Ichthyosaurs were large marine reptiles with an aspect between fish and dolphin. Werereptiles, which through evolution and centuries, returned to the water. As did the whalesand dolphins, mammals that returned to the sea mainly in search of food.

Within the ichthyosaurs, are the Shonisaurus sikkanniensis. A species that is possiblythe largest marine reptile so far discovered. Although little intimidating appearance, their size allowed devour large and fearsome creatures as giant squid and fish andother smaller reptiles.

His mouth was three meters long (similar to Liopleurodon) and body size is estimatedat 21 meters. Other animal related to Shonisaurus popularis Shonisaurussikkanniensis was 15 meters long. But let's focus on the S. Sikkanniensis.

Her body was among whale and dolphin, but then she was a reptile. Their wings werehuge, his bones as well (the ribs came to be more than 3 meters) and weighs 40 tonscould reach easily.
By the way, lived in the Triassic.

Curiosity: The majority of fossils have been found in the Shoshone Mountains at an altitude of about 7000 meters above sea level.

Hurdia Victoria.

2011-01-11T02:40:00.000-08:00

The further back in time, the prehistoric animals are rare, most unique and peculiar to our eyes. First adjustments, tests and experiments of evolution that is distributed andbranches, people still just a piece of a twig of the tree .... or less.500 million years ago during the Cambrian, appeared in the seas and oceans a trulystrange, like a squid but with teeth, larger body and gills was easier to pick up oxygen from the water and move faster. This is the Hurdia Victoria. Anomalocaris close relative to similar in many respects.

The Hurdia Victoria was a top predator of its time, ate many species with basic anatomical models and dominated the seas and oceans and the creatures of their time. Keep in mind that during his appearance was the Cambrian Explosion and manynew species were appearing and taking their first steps on dangerous waters and old.

And how was the Hurdia Victoria? Well, this prehistoric animal that is considered an ancestor of the arthropods, the large group that includes insects, crustaceans, spiders,millipedes and Chilopoda; could measure about 50 cm, which is giant compared tomost animals at the time.

His head had a couple of thorny claws (appendices), which helped carry food to hismouth, like a slice of pineapple. He had a hole in the pointy bump on the front of hishead, although the function of this organ remains unknown, since no protection couldhave been because there is underlying soft tissue. He lobes along the sides of the trunk, which were suspended large gills.

Predator and scavenger (supposedly) is considered by experts as the TyrannosaurusRex of the Cambrian.

Kaprosuchus saharicus.

2010-12-22T01:35:00.000-08:00

Kaprosuchus saharicus was a huge crocodile that lived in the Upper Cretaceous in Niger (Africa). This dinosaur is not extremely large as it could be other prehistoriccrocodiles as Deinosuchus or Sarcosuchus Imperator. "Only"average 6 meters but what is striking is his face. He had a terrible predator face, large protruding teethabove and below the jaw and a rough bump on the snout (emerging from thesquamous and parietal) giving it an aggressive appearance that recalls when wolvesbaring their teeth defensive position . We, as the most terrible dragon fantasy filmstoday.

Another difference between the Kaprosuchus saharicus and other crocodiles is thatthe basins of the hojos projected forward, not upward. Had stereoscopic vision, similar to the hunters like lions or wolves.
In fact, this animal was a predator prehistoric Earth, but also water. Because land isattributed hunter strong legs that allowed him to pursue their prey with great speed and run at a certain height from the ground (to be cococrilo).

Finally, thanks to their appearance, their disproportionately large, sharp fangs, was given the name of Kaprosuchus, meaning crocodile boar. Referring to the tusks of theboars that tend to stand out from the muzzle. And saharicus that their bones werefound in the Sahara.

Gigantoraptor.

2010-12-03T02:16:00.000-08:00

The Gigantoraptor is half bird, half dinosaur, not known, but what is .... is that it is a mystery.

Discovered in 2005 in the Gobi desert, lived 80 million years ago in the land of the Cretaceous period.
Its resemblance to the birds include anatomical features such as a peak instead of teeth in the jaws and the possibility of being covered with feathers. That's why we think it is the largest winged animal that has never existed. Whether flying or not.

Another question that appears on this prehistoric animal, half dinosaur, half bird, is your diet: it is thought that it was herbivorous, but on the other hand, has strong claws and is regarded as agile and fast moving, predatory characteristics. In short, we'll know later.

But how long the Gigantoraptor? For their measurements are 5 meters (17ft) tall to 8 meters (26ft) long and weighing about 2 tonnes. Oviraptoridae family, is the oldest. The Oviraptoridae are a group of dinosaurs known to include many feathered species. Gigantoraptor was much larger, about 35 times larger than its likely close relative, Caudipteryx.

Kelenken guillermoi.

2010-11-30T02:46:00.000-08:00

Some time ago we spoke of wallerian Titanis, the second largest bird of the subfamily Phorusrhacidae, or better known as terror birds. It should be noted that in the Subfamily Brontornithinae Terror Birds are heavier and bigger as the bird Brontornis.

Phorusrhacidae and Brontornithinae are subfamilies of the family of Phorusrhacids.Anyway, on with the Kelenken.

The largest bird is the Kelenken guillermoi. He lived in South America 15 million years ago (Miocene), recall that lived in North America wallerian Titanis for 5. And he could measure up to 2.5 meters tall and weigh about 160 kg elenken was quick and could hunt and devour rodents, reptiles and small mammals.

It is the largest known predatory bird in history. And not just any predator was in the top of the food chain, and could face other super-predator of the time.

Two features of Kelenken guillermoi my attention:

1 - The size of the head: This came to be more than 70 cm long, with the bird known as the largest skull. Imagine a large ostrich, but with a pointed beak and hook and 7 times larger. All supported by a robust and strong neck.

2º-

2 - The second thing that strikes me is the speed: I could outrun an ostrich. The ostrich is known for the speed provided by its two strong legs, reaching up to 65 km / h. The Kelenken guillermoi being young could reach 100 km / h. Come on, that may strike a galloping horse without difficulty.

Procoptodon Goliath.

2010-11-01T09:31:00.000-07:00

This huge kangaroo lived in Australia until 18,000 years ago and apparently, the man was partly to blame. And although it is unclear the role of men in ending the Procoptodon, seen the Holocene mass extinction that occurred mainly men (apart from climate change), I have been surprised that Aboriginal Australians. But hey, that's just my opinion.

The Procoptodon measuring 1 meter current that kangaroos and reached weigh 250 kg (2 ½ times more than the actual red kangaroo with an average height of 3 meters.
These giant short-faced kangaroos had their eyes facing forward. At the foot had just pointed a long finger-shaped arrow. With these strange feet moved quickly through the woods and meadows, where he ate grass and leaves. He had long arms.

Tiktaalik

2010-10-21T13:33:00.000-07:00

Tiktaalik was primarily the characteristics of a fish, but with the tips forming skeletal structures similar to an arm, similar to those of crocodiles, including shoulder, elbow and wrist. He had the sharp teeth of a predator, and his neck could move independently of his body, it is not possible in other fish. The animal also had a flat skull like the crocodile eyes on the top of the head, suggesting that spend much time looking up, neck and ribs like those of tetrapods, which will serve to support the body and help to breathe through lungs, a long snout can catch prey on land, and a gill opening, in higher animals, would subsequently become heard. Its discoverers felt that, in all likelihood, Tiktaalik flexed its proto-limbs in the main river bed and could have pushed himself to the shore for brief periods. These specimens reached a size of 1.2 to 2.75 meters.

He lived in the Devonian period about 375 million years.

Excellently preserved remains of Tiktaalik in 2004 were found on Ellesmere Island in Canada.

Along with Ichthyostega, Coelacanth and Acantjostega is one of the prehistoric animals that show as was the transition from fish to tetrapod.

For more information:
Wikipedia.
http://www.nodo50.org.

Triops cancriformis. The oldest animal in history.

2010-10-02T23:40:00.000-07:00

This animal is a Triops cancriformis, is considered the oldest prehistoric animal still exists. It is truly a living fossil appeared on earth 200 million years ago (Triassic).
The discovery of this species was by accident while researchers at the University of Glasgow mud collected for further experiments.
The crustacean Triops branchiopods cancriformis are some belonging to the order of Notostraca. Receive various common names, such as turtles or tortuguetas.
The Triops has three eyes, two compound eyes internally and naupliar eye in between, a flattened oval shell that covers the head and body segments bearing appendages. Found at the bottom of ponds and lakes, where they move with the belly down. In case of shortage of oxygen, it may swim belly-up on the water surface, are omnivores, and dig into the bottom of the puddles in search of food. Their diet is based on plankton, insect larvae, worms and even tadpoles when they are weak. You can also watch Triops cannibalism during moulting of the shell as they are more susceptible to predation.

Its life cycle is very fast and is perfectly adapted to drought. Eggs buried in dry mud can withstand heavy frosts during the winter and hatch in 2 or 3 days with the humidity of the first rains, but is required a minimum temperature of 23 degrees centigrade for it. Triops youth, with an omnivorous diet, begin feeding frenzy around what they find. Navigate through the bottom digging in the mud and prefer to feed on plant detritus but if this scarce eat tadpoles, conspecifics artemia or when moving the shell and are more fragile. Reach a height of 10 cm and grow old and die before the month and a half of all offspring leave they can. If males are scarce, as is usual, the females can reproduce by parthenogenesis without the collaboration of these. The eggs can travel in the mud that sticks to the legs of the birds that visit their ponds and so can spread throughout its range (Europe), plus they can remain latent for years.
They are fairly easy to breed in captivity and there are virtual shops on the internet that sell bags of eggs to keep them in aquariums.

Do not you remember the Paradoxides Davidis?

Anomalocaris.

2010-09-14T14:07:00.000-07:00

During the Cambrian explosion of life (for about 525-510 millions years. Up to this point had not been very successful multicellular life) appeared the first predator to bite, was the Anomalocaris. The biggest predator of the Cambrian seas. Measure up to 1 meter and its name means "strange shrimp."

Possibly it was given this name because when they discovered the fossils were so strange that they thought of three different animals.

It had a segmented body, such as some crustaceans and a current "arms" armed with thorns, compound eyes (with a very developed on their prey, but not entirely confirmed). The mouth was circular and had 32 overlapping layers (four large and 28 small) equipped with small barbs which failed serrated rings around a central opening. With his arms gripping the defenseless Pikaia or trilobites and pounding and crushing.

Like trilobites, the Anomalocaris was an arthropod, bony internal skeleton had not, this was a protection mechanism, a cuticle or exoskeleton made of chitin and proteins such as cuticulina.

Curiosity: A recently described a new species closely related to Cambrian Anomalocaris the Hurdia victoria.

Daeodon. Pig or boar terrible.

2010-09-05T23:39:00.000-07:00

Entelodon has long talked of a huge boar, terrible and effective predator. Well, Daeodon was further developments. It was a little larger, reaching 3.6 meters long and 2 meters high. With a head of more than 1 meter in length that had a strong jaw with a bite (similar in proportion to the actual pigs and wild boars) and large and deadly fangs. The neck was short and thick and had a hump on the back along the spine.
With a strong and robust body reached a speed of 35 km / h, and managed to bring down their prey in the form of ambush and was once a short distance faster than performing a surprise attack their prey and bite and squeeze your strong bite.
He lived during the Miocene, about 24 million years ago in North America.

Among the causes of their extinction is thought to be one of the reasons was the gateway to the continent of Bear-dog or Amphicyon. More agile and fast and safely with a structure similar to the wolf pack that offered a performance at top predator.

Is it possible to resurrect prehistoric animals?

2010-08-30T09:37:00.001-07:00

Is it possible to resurrect prehistoric animals?

If we refer to dinosaurs as depicted in the film Jurassic Park, it seems that currently it is impossible not to resuscitate. While experts are very excited to think that in future it may be.
Apparently it has been able to recreate a living ... but very simple ... is actually a bacteria. Pour bacteria (Mycoplasma mycoides) is the first time you create a synthetic life form. To achieve this, the researchers built a machine in his laboratory every one of the basic units of DNA of the bacteria 'Mycoplasma mycoides' and assembled as if it were a Mecano. Once assembled the intricate puzzle, emptied a cell of another species of bacteria and introduced the synthetic genetic code in the cell container. And that's it ...
But of course, there are limitations:

1st - The Pour bacteria is very simple, basically a membrane genome, but in more complex organisms the DNA is packaged in the nucleus. And no one, until now, has been able to empty the heart and inject DNA into the interior.

2 - DNA sequences tend to deteriorate over time, and it is very difficult to draw a complete map of animals that lived millions of years could be the known T-rex. However there are other prehistoric animals, and extinct, are possible candidates ... as recently extinct and has obtained a DNA map comlete. Saber-toothed tigers, mammoths, cave bears, Tasmanian tiger, woolly rhinoceros, giant sloth and even our cousins the Neanderthals. All of them disappeared less than 100,000 years ago.

3 - There must be akin to a living animal which wants to revive, for example, to the mammoth elephant would be required to insert the embryo. But of course, to resurrect the kind of Neanderthal what it would take would be a woman. And this will bring much discussion and many different opinions, which I think could be done though, many voices that would oppose it.

4 - The environmental conditions of animals are now missing, in some cases, nonexistent. And basically serve as scientific purposes. There are no dams Sabretooth or frozen grass to keep Mammoth.

Well, I always think I conclude with this question: If you could resurrect a Neanderthal, what do you think think a Neanderthal resurrected in our world?

The famous Bear-dog or Amphicyon

2010-08-22T00:07:00.000-07:00

Imagine the world's largest wolf, and now doubling in size, finally give steroids to duplicate the musculature. Throw in claws bigger than a grizzly with a strong legs to run and reach high speeds ... That leaves us? As a predator that existed from the mid-Oligocene and early Miocene. His name was Amphicyon ingens (dog ambiguous) or commonly known as Bear-dog.
This prehistoric beast could be up to three meters and weigh up to 400 kg. Given its size, you might think was not very fast, but do not be fooled, it is thought that hunted their prey in ambush and surprised with a quick career. The smell was due to an as refined as a bloodhound and a fine ear. Type of game similar to the great bears today. He could hunt animals as robust as the old giant sloths or rhinos.

He lived in Europe and Asia and later introduced in North America by the Bering Strait (humans migrated from Asia to the Americas through the strait, possibly taking advantage of a glacial period and the freezing of the Sea) competition in North America other carnivorous even more ... the Daeodon or "terrible pig."

Abelisaurus or Abel's lizard

2010-08-11T01:15:00.000-07:00

At the end of the Cretaceous period in what is now South America, approximately between 83 and lived 80 million years ago the "Abel's lizard" or Abelisaurus. With a skull up to a meter and sharp teeth this carnivorous predator of between 7 and 9 meters (25 to 30 feet)long and weighed about 3000 kilograms, were living with other predators such as known Tyrannotitan or Carnotauros, fierce competitors for the same prey as old tyrannotitanes patients. The Carnotaurus, was probably a abelisaurid early, scientists assume that Abelisaurus also had front legs short and slender limbs.

The discovery of Abelisaurus is important because it sheds light on many theropods (carnivorous diet and walking biped with three fingers to the front and provided with sharp claws) than the southern hemisphere that were very different from their relatives in the northern hemisphere. This was the result of the separation of land masses of North and South that began in the Jurassic period.
Not go into the morphological differences ... anyone who wants to know them I invite you to search Wikipedia.

Hyena giant or Pachycrocuta Brevirostris.

2010-07-28T02:45:00.000-07:00

Famous is the force that have the jaws of the hyenas that can reach pressures of 350 kg (600lb)and teeth grinding of hard bones and teeth and hooves. Well, now imagine a hyena twice as big, twice as strong and a powerful jaw twice ... this animal there was Pachycrocuta brevirostris.

Pachycrocuta a genus of prehistoric hyenas. The largest specimen, well-documented part of the species of giant hyenas Pachycrocuta brevirostris. With a height of 1 meter (39 in) and weigh up to 120 kg (250 lb).Un similar in size to a small lioness.
This size would make it the largest of the hyenas that have ever lived. He lived from the Middle Pliocene and Middle Pleistocene, about 3 million and 500,000 years ago.
Found fossils in Eurasia and southern and eastern Africa. In dens, caves used as dens.
Scavenger and a predator could be stubborn and tenacious to deer hunting big and small package was probably a hunter of large animals (up to larger deer and occasionally as Megaloceros). The chance of a scavenger is sensed it was a very big animal not built for chasing prey over long distances. In this aspect would have differed from today spotted hyena, which is a more agile animal that, contrary to his image of the documentaries, also kills his own food. Apparently it was ecologically close enough to the smaller (but still important) in relation perrieri Pliocrocuta never found as fossils contemporaries in the same region.

This is a very beautiful reconstruction extracted qi.com

Cheetah Giant or Acinonyx pardinensis

2010-07-21T23:32:00.000-07:00

The problem that presents itself now is the cheetah who specializes in speed, his muscles has focused on this goal. That's why the dams are often stolen by other predators such as lions, hyenas, leopards even African dogs. Well, there was an ancestor who lived in the Quaternary, the Pleistocene (over 1 million years) and with a size twice as large as the current cheetah, reaching weigh over 120 kg (264 lbs)and over 2 meters long excluding the tail(6 feet 3 inches). High BMI, used more nails (in comparison with modern cheetahs), suggesting that it was less suited to high speed, although it is believed that he could reach over 70 mph(lower than the current but faster than everyone else cats. We must remember that current Cheetahs reach speeds of 115 km / h.
But this theory suggested by the great weight is offset by the antithesis: you think you might be even more than the current cheetah because its legs were of a larger size.
Because of its bulk, it needs to go very fast after prey. Deer, mountain goats, moose and sambar (deer species) were their prey.
It is thought that went extinct 10,000 years ago.

Cynognathus.

2010-07-01T12:43:00.000-07:00

The size of a large dog, this therapsid (reptile-like mammals) was a terrifying predator of the prehistoric period. He lived in the Triassic and Lower Jurassic (made between 245 and 208 million years ago) in what is now South Africa, Argentina, China and Antarctica. It was one of the most impressive land predators of its time.
Praising Cynognathus fossilized skulls of openings have been observed at the height of the snout, typical skulls of mammals, where vessels and nerves pass supplying the whiskers, similar to cats and dogs. So you think you had hair, and that these particular should serve as sensory organs.
With almost two meters long (6.3 ft counting the tail) and a head of 30 cm (1.0 ft) with wide jaws and sharp teeth, its bite was strong and had to exert great pressure (similar to today's crocodiles with 2500 kg of pressure.
The Cynognathus was an agile runner and can reach a speed of 35 km / h. .. conclusion was a very effective and powerful carnivore.

Colossochelys atlas or Testudo atlas

2010-06-15T04:50:00.000-07:00

Testudo atlas or Colosoqueli, was the largest turtle. It was, to get a great idea to double that giant tortoises that live today. Reached 2.5 m in length, a height of 1.5 meters and 4 tons.
His legs, like an elephant, were projected on the sides of the body and held the heavy shell of the back. The almoahadillas in the soles of his feet compact distribute the great weight among the five fingers of each leg, with robust claws. It was probably herbivorous and their relatives today. Faced with danger, could get his head and legs in heavy bony armor to protect themselves.
Testudo atlas or Colosoqueli lived in South Asia more than a million years, Pleistocene.

In this video you can see a current Giant Tortoise. It should be intoaccount the Testudo Atlas, could weigh up to more than 15 times its weight.

Curiosity: Although the Testudo atlas or Colosoqueli is the largest turtle that ever lived, not the animal that has existed more shell. This would be the Arquelón 3.7 meters long. This is a sea turtle extinct.

Estemmenosuchus

2010-06-05T01:36:00.000-07:00

Estemmenosuchus prehistoric animal was a big and clumsy. Similar to the current rhino. The Estemmenosuchus "crocodile crowned" is named by the horns formed from the bones of the skull that are in the front and are directed upward.
He lived 225 million years ago in what is now Russia, the Permian period. Being the largest of its time with the Dimetron.
For the fossils found in the skulls, it is thought that it was an omnivore.
There are two known species of Estemmenosuchus:

1 - Uralensis Estemmenosuchus ("crocodile Coronado Urals). The characteristics of the species are the horns projecting up and out on the side of the head. Since this kind of about 4-5 meters long. The mouth contains large canines followed by small molar teeth.

2 - Estemmenosuchus mirabilis (wonderful Crocodile Coronado). This species had bony projection 2 knobs on each side of the skull, one on top facing upwards apparently pointing horns and other similar sides uralensis.

Dimetron.

2010-05-23T08:02:00.000-07:00

The dimetron, was not a dinosaur but looked very similar. In fact it is closer to the first mammals to reptiles.
This ancestor of mammals was the dominant predator of its time, during the Permian period of the Paleozoic era, made between 280 and 260 million years.
Could reach 3 meters long and had a long tail. A short legs and an elongated body provided them with a motion similar to those of the current monitors.
Another feature is its teeth Dimetrón two different types of teeth: a Shredder and a very sharp cuspids heartbreaking.
But the most distinctive feature is the spectacular dimetrodonte sail on its back. The candle used it, probably, to regulate body temperature because their large surface area allowed to warm up or cool efficiently. The flap was supported by the neural spines, each one sprang from an individual vertebra. You may also wear the dorsal fin in the courtship of mating or to ward off other predators.
The Dimetrón was a fierce predator that used two pairs of sharp pointed canines for tearing the skin of their victims. With the jaws closed, the Dimetrodon appeared to be smiling, but when he opened and showed his wide mouth, his appearance was not friendly at all. His jaws were so large that probably could devour animals of the same size.

Nothosaurus

2010-05-04T14:27:00.000-07:00

Nothosaurus is an extinct genus of sauropsids (reptiles) Triassic marine, was among the first plesiosaurus (like the famous Elasmosaurus). Its name means "fake lizard" and who were not lizards like today's or even a dinosaur.
His teeth, very sharp as daggers, which also fit together those in both jaws, was a perfect trap for fish. Nothosaurus could close the mouth with great force but the muscles that allowed him to reopen it were very weak. Some of the best preserved fossils preserve the skin and drawing show that Nothosaurus had webbed feet, suitable for both the aquatic environment and to the land.
They could spend part of their life on land, on the sand and rocks. The tips allowed them to walk and move awkwardly arched his back, like lions today. You probably arrived on shore to stretch out, relax and warm in the sun, capturing prey on the pools of the shore and to reproduce by laying eggs. Breathed air, as shown by the two nostrils at the top of his nose, and although it was undoubtedly a stylish swimmer, was not so well adapted to an aquatic lifestyle as full-time as Opthalmosaurus ichthyosaurs.

Giant wolf or wolf terrible.

2010-04-27T23:38:00.000-07:00

The terrible giant wolf or wolf is a species of extinct large canine that lived in North America during the Pleistocene. Certain features present in this field, suggests that dire wolves, like many other dogs, were social animals who lived and hunted in packs.
Although invited to think what its common name, the giant wolf was not exceptionally large compared with its relative, the common wolf or gray wolf (Canis lupus.) On average, weighed about 80 kg. However, the differences with the other canines, with whom he shared habitat for 90 000 years, are important.
Canis dirus was more robust and proportionally shorter legs, so that it would be a great runner. The nose was long and powerful jaws, thick, strong teeth capable of crushing bones. All this suggests that animals hunted cumbersome, injured or ill, and often feed on carrion. The niche occupied by meadows and steppes in the North American ice age was similar to that hyenas had on other continents. A large number of fossils of herbivores crushed by the jaws of giant wolves reinforce this idea.
Probably became extinct 10 000 years ago, like the rest of the American megafauna.

Some fossil discoveries made in Arkansas indicate that could live in the Ozark Mountains until only 4000 years.

To read more http://es.wikipedia.org/wiki/Canis_dirus

Giant deer or Megaloceros

2010-04-21T12:02:00.000-07:00

The Irish elk, Giant deer Megaloceros deer is the largest in history. Like a large deer, his antlers were up to 3.5 m from tip to tip. Although he lived in Europe and much of Asia for half a million years to extinction in recent times, often known as "Irish elk" for the abundant findings of specimens preserved in the peat bogs of Ireland.
The giant deer reached a height of 2.2 m to the cross in the case of males, significantly higher than the largest of the moose. It was a species with strong sexual dimorphism, as females were significantly smaller and slender than the males, in addition to lacking an impressive antlers.
The giant deer grazers were animals that thrived on abundant grass and shrubs in the large, cold plains covering much of Eurasia during the Pleistocene.
Antlers were so large that it required large amounts of calcium and phosphate to form occurring cases of osteoporosis among male Irish elk, so that mortality, already high, increased in bad years.
This fantastic animal became extinct only 7000 years. Were extinguished by changes in the field that were caused by early Neolithic farmers Russian.

Macrauchenia ( Macrauchenia patachonica. )

2010-04-13T00:11:00.000-07:00

The Macrauchenia is an extinct mammal with a body of a camel and a short trunk, reaching two and three meters long. (9.8 ft) with 1500 Kg of weight. Dwelt on the plains of South America in the Tertiary and Quaternary disappearing more than 8500 years ago. Despite having long-legged three-toed ungulate is unlikely to run at high speed due in part to the robust frame of body and hind legs that were shorter than the front. Age of herbivorous, eating in areas where I spent most of his time as swamps and grazing, provided him with his prehensile lip boot pastures. Its fur was short, similar to that of a modern horse. He had a trunk like they were today tapirs.
Contact with the men contributed to their extinction, as hunters have taken advantage of its low travel speed to kill and eat.

Hoplophoneus

2010-04-09T10:46:00.000-07:00

Hoplophoneus is an extinct genus of carnivorous mammals that lived in North America during the Eocene-Oligocene (38-33,3 million years ago).

It was the size of a leopard, with a stocky body and short legs, and about 40 kg in weight.

Also had a groove in the lower jaw where they settled long saber-like canines of the upper jaw, but never to be considered a saber tooth. Experts believe that this mammal patiently perched in the branches of the trees and then jumping on their prey and causing fatal injuries with long, sharp fangs.

The Hoplophoneus was similar to cats, although they were not. The structure of the inner ear bones are different, the cats have an external structure called the auditory bulla separated by a partition into two chambers, the lack nimrávidos noise.

Curiosity: As Eusmilus, the Hoplophoneus, had teeth that hid when not in use, the cat kept his fangs in special bags adapted in the lower jaw .

Andrewsarchus or "androsarcus"

2010-04-09T09:40:00.000-07:00

The Andrewsarchus is related to the sheep and goat, but has wolf's clothing. Mmífero was a giant of the time. It has a meter jaws, and scavenger. They lived in the late Eocene.
He walked on four short legs and a long body, long tail, and feet with hoofed toes. He had a long snout with large, sharp teeth and flat teeth may have been used to crush bones.
Had a length from snout to the back of the pelvis of about 3.4 m and a height from the ground to the shoulder or mid-back of approximately 1.5 m. Probably weighed about 1000 kg
Your diet may have been more carnivorous and omnivorous that is not yet clear whether he was a hunter or scavenger, because the teeth are more characteristic of a scavenger with teeth grinding.
He is considered the largest known terrestrial carnivore to date.

Sauroposeidon, The largest and heaviest dinosaurs of Earth's history

2010-04-07T10:56:00.000-07:00

The Sauroposeidon who lived during the Cretaceous, in what is now North America, is the largest known lizard, long and weighing of all land animals throughout the history of the Earth. Hence its name, which means "lizard god of earthquakes."
This vegetarian sauropod is ahead in size and weight above Argentinosaurus, Ultrasauros and other sauropods.
Well, the Sauroposeidon reached 17 meters in height (as a 6-storey building) and weigh up to 60 tons (more than 10 African savannah elephants together) and a length of 35 meters (100 ft).
To give an idea of what was long enough to know that one of his vertebrae could be up to 1.20 meters long (4 ft). And only the neck measuring up to 12 meters (37–39 ft).

This is why it is ranked as the longest dinosaur history.

Ultrasauros.

2010-04-05T12:02:00.000-07:00

These amazing animals are among the heaviest dinosaur that ever lived. Although his body resembled that of other sauropods, surpassed in size to most of its peers. It was about 25 times heavier than a giraffe long as three buses and as tall as a six-story building. Its neck and tail, incredibly long, were supported by a backbone like a grill. At the sides of the vertebrae, there were some openings that reduce weight without weakening his back. Most of the weight of its giant dinosaur bore members. Therefore, major bones were the blades, connecting the front legs with the body. The was large and strong, each of them would be higher than a soccer goal. His back was lower than their shoulders, as the hind legs were shorter than the front. When grazing among the plants and bushes, swinging his long neck in all directions. It could reach the juicy leaves of higher tops and low ferns. I needed lots of vegetation, cutting his teeth beveled. For easier digestion, probably swallowed small rocks that were deposited in your belly and helped to turn plants into pulp. Although hard to imagine, experts have suggested that brachiosaurids like this, roamed in herds slowly advancing. Surely the ground shake under their feet. The sheer size of an animal as this dinosaur probably deterred most predators living at the time. But if one is away from the bequest, was exposed to grave danger. On the inside of his legs, like those of elephants, had a sharp claw. With an accurate kick and a flick of its tail flexible, could bring down his enemy. Measuring up to 30 meters long and a little more than 15 high. It lived about 145 million years, at the end of the Jurassic period in North America.

Curious: There is another dinosaur called Ultrsaurus, but not the same, is smaller and fossils found in Asia.

Henodus chelyops.

2010-03-25T00:04:00.000-07:00

Henodus chelyops ("Turtle-Faced Single Tooth") was a placodont of the Late Triassic period during the Carnian stage. Fossils of Henodus chelyops were found in Tübingen, Germany. It was around 1 metre (3.3 ft) in length.
Henodus was the placodont that had the greatest (albeit superficial) resemblance to a turtle. Like turtles, it had a shell formed from a plastron on the underside and a carapace on top. The carapace extended well beyond the limbs, and was made up of individual plates of bony scutes covered by plates of horn. However, the shell was composed of many more pieces of bone than that of turtles, forming a mosaic pattern. The armor was fused to its spine, and its limbs were situated in normal positions, unlike the turtle, where they are located inside the ribcage. The weak limbs of Henodus suggest it spent little, if any time on land.
Henodus chelyops also had a single tooth on each side of its mouth, though the remaining teeth were replaced by a beak. These teeth were flat to crush bottom dwelling shellfish. The head was squared-off at the front, just ahead of the eyes.
Henodus is the only placodont thus far found in non-marine deposits, suggesting it may have lived in brackish or freshwater lagoons.

Helicoprion

2010-03-15T13:37:00.000-07:00

Helicoprion is a prehistoric cartilaginous fish that first appeared in the Carboniferous ocean finally extinguished in the Late Triassic, about 225 million years.
Helicoprion is thought may have reached a size of about 7 meters long and about 2 tons.
Since you do not have any skull, his way of feeding or predation techniques fall within the realm of speculation. One hypothesis is that fed on ammonites and their teeth were specialized in the task of breaking the shells of these animals.
Have been found in many parts of the world, which indicates its success in a given period.

Here I leave some pictures of different artists and their fossils.

Giant castor.

2010-03-07T08:55:00.001-08:00

The beaver is an extinct giant rodent Castoridae family. It is one of the largest rodents that ever existed, which reached the size of a bear. He lived about 50,000 years ago during the Pleistocene in North America.
He used his teeth to chew tough vegetation and bark, was a good swimmer, but did not build dams. Other types of beaver build dams to protect themselves from predators but in this case was protecting its own gigantic size, were found fossils of giant Castor from Florida (southern U.S.) to northern Canada.
Unlike the current beaver had a wider rear legs relative to its body, making it easier to swim faster.
Other differences are observed in the teeth. The cutting teeth (incisors) of the giant beaver were up to 15 cm long.
Despite their general similarities, the giant beaver and the modern beaver are not close relatives. The giant beaver Castoroides is classified in the genus, while the modern beaver Castor belongs to. There are two species of beaver giant Castoroides Castoroides ohioensis and leiseyorum.

Therizinosaurus

2010-02-10T08:33:00.001-08:00

The Therizinosaurus was a bipedal animal with vicious prehistoric claws was found in Mongolia (Asia)
THE Therizinosaurus measuring up to 12 m long. His weight was up to 6 tons. The total arm measured 2.5 meters long, and his only scythe-shaped claw measuring 70 centimeters in outer curve. That length does not include the horny covering that must have surrounded the claw, with which it could reach up to 1 meter long.

Therizinosaurus ( "scythe lizard") lived in the Cretaceous (for about 70 to 65 million years in the Maastrichtian).

He lived together with other prehistoric animals like the striking resemblance and Erlikosaurus Segnosaurus.

Are unknown Therizinosaurus eating habits. These are unknown as fossils found in was not found remains that may determine your diet. He may have been herbivorous although the claws may be possessed for the struggle to defend territory or to mate, even to defend themselves from predators like the Tarbosaurus.

Crassigyrinus scoticus

2010-01-30T23:56:00.000-08:00

Crassigyrinus scoticus (large tadpole) had a streamlined body up to 1.5 meters long and 30 cm wide.
The prehistoric animal legs were small in comparison to his body and probably of little value, this indicates that the Crassigyrinus scoticus was perfectly adapted to aquatic environments and did not venture in land area.

The highlight of the Crassigyrinus scoticus was that he was big and strong jaws, equipped with two rows of sharp teeth.
Studies have shown that this Carboniferous animal had a jaw opening up to 60 ° can easily catch their prey. To this we must add a lot of pressure that made his jaw bite one of the most fearsome of the time.

The jaw opening and the speed and agility that gave it its long body and aerodynamic, suggests that between prey fish came fast movements.

Crassigyrinus had eyes rather large, thereby helping to find prey in dark places or in murky water.

This prehistoric amphibian lived in Europe (fossils have been found mainly in Scotland) during the Carboniferous.

Megalosaurus.

2010-01-04T12:19:00.001-08:00

Megalosaurus was a predator of some up to 10 meters long and weighing 1 t. He lived in what is now Europe, America, Asia and Africa during the Jurassic period, 181 made 169 million years.
Among their prizes were sauropods, large prehistoric animals and stegosaurs and mammals.
Besides being a fast predator, with speeds that could reach 40 km / h thanks to its well-balanced structure, the Megalosaurus also got their food scavenging.
The Megalosaurus was one of the first dinosaur discoveries, England 1818. At that time, and seeing the fossils found, these bones were so enormous that gave its name Megalosaurus (great lizard).
The jaw of Megalosaurus had teeth long and curved, strongly subject to the gums to avoid losing in the struggle. The teeth were sharp with the corrugated edge that worked like a saw. Ripping a more efficient prey.
To make matters worse, had prehistoric animal with sharp claws and tear that held the hard skin of the victims.

Ceratosaurus

2010-01-02T00:06:00.000-08:00

The Ceratosaurus had skulls with a structure similar to the dorsal horn on the snout, centrally placed in the nasal cast. They had fused sacral bones (Synsacrum) and the pelvic bones together and held together this structure. A row of small bony nodules or osteoderms were presented under the middle of the back.

The Ceratosaurus could have competed with Allosaurus and Torvosaurus for the same prey (giant sauropods Diplodocus, Apatosaurus and Camarasaurus), but this was smaller by about 6 to 8 meters in length, 2.5 in height, and weighing from 500 kg to 1 tonne would have an ecological niche occupied separately from their larger cousins. Moreover, the Ceratosaurus had a longer body and supple, with a tail shaped like a crocodile. This suggests that was a better swimmer and Torvosaurus Allosaurus. A recent study showed that Robert Bakker Ceratosaurus dams usually hunted waterfowl, such as fish and reptiles, but also had great potential to feed on dinosaurs. The study also indicates that adults and juveniles sometimes ate together. This evidence is, of course, very debatable and Ceratosaurus teeth marks are very common in large dams fossils of dinosaurs on land. Another common theory is that the Ceratosaurus has preyed primarily on Dryosaurus, Camptosaurus, and other ornithopods, since it seems a Lonely Hunter adults unable to break down sauropods. An alternative is that the ceratosaur eat carrion of large bodies of sauropods, displacing small small predators.

Ceratosaurus ("lagarto cornudo") que vivieron a finales del período Jurásico, hace aproximadamente 152 y 145 millones de años, en el Kimeridgiano y el Titoniano, en lo que hoy es Norteamérica, África y posiblemente en Europa.

Josephoartigasia monesi

2009-12-29T08:25:00.000-08:00

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.

2009-11-09T01:02:00.000-08:00

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

2009-11-03T08:23:00.000-08:00

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.

PALEONTOLOGUE : Iguanodons
Cargado por NigelMarvin. - Ver videos desternillantes de animales.

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

2009-10-16T00:39:00.000-07:00

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.

2009-10-07T00:01:00.000-07:00

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

2009-09-30T01:07:00.000-07:00

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

2009-09-28T02:07:00.000-07:00

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

2009-09-26T04:19:00.000-07:00

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

2009-09-22T08:42:00.000-07:00

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.

2009-09-16T08:14:00.000-07:00

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

2009-09-14T11:46:00.000-07:00

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.

2009-09-09T13:30:00.000-07:00

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

2009-09-06T01:10:00.000-07:00

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

2009-09-02T08:33:00.000-07:00

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

2009-09-01T14:35:00.000-07:00

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

2009-08-24T13:32:00.000-07:00

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.

2009-08-21T08:15:00.000-07:00

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

2009-08-20T08:29:00.000-07:00

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

2009-08-18T12:37:00.000-07:00

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

2009-08-17T08:31:00.000-07:00

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

2009-08-16T15:12:00.000-07:00

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

2009-07-28T01:01:00.000-07:00

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

2009-07-24T04:43:00.000-07:00

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

2009-07-24T00:14:00.000-07:00

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

2009-07-10T09:15:00.000-07:00

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.

2009-07-10T09:05:00.000-07:00

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

2009-07-07T10:23:00.000-07:00

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.

2009-07-06T15:26:00.000-07:00

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

2009-07-05T14:23:00.000-07:00

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.

2009-07-02T13:38:00.000-07:00

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.

2009-07-01T00:19:00.000-07:00

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

2009-06-30T00:30:00.000-07:00

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.