Evolution: the Purgatorius to men.

In the great debate of the past (I now passed) between creationism and evolution were the remains of an animal as Purgatorius which tipped the balance in favor of supporting the evolution.

The Purgatorius is an animal with an important role in the evolution of man, is considered the protoprimate (ancestors of the primates) older, but their taxonomic position is uncertain. It has been argued that Purgatorius was an ancestor of primates and the Plesiadapiformes (an order of extinct mammals).

Paleontologists have found fossils of this mammal along with other fossilized remains such as the T-Rex when it happened the great extinction of the dinosaurs 65 million years. It is one of the survivors of this great catastrophe. He survived the cataclysm that caused the famous meteorite impact that ended the reign of the great reptiles and gave way to the evolution of other kinds of animals negligible so far.

In short, it is believed that if he had not resisted Purgatorius extinction, hibernating in deep burrows and feeding on roots and bulbs, we would not exist.

It was a small mammal of about 15 cm long (like a small rat) and one kilogram. He ate everything (omnivorous) and may feed on plants, fruits or meat scraps toast of a Triceratops.



Austroraptor

 




The Austroraptor is a close relative to Velociraptor, but larger, about 20 feet long (3 times longer). His name means "thief of the South" (South raptor), such as birds, and do not put this name by chance. In a way, his appearance might remind us old birds, a predecessor to the Raptors next we Know today. His head (over 4 fts) was low, long and streamlined, provided with numerous small and conical teeth. Moreover, according to the markings found in fossils, it was covered with feathers.

This prehistoric animal called attention to the paleontologist who discovered it to see how their upper limbs were in proportion smaller than others of the same gender: their short forearms depart from the condition characteristic of all long arms and their relatives dromaeosaurids avian nearby. This would therefore be a missing link between dinosaurs and modern birds.
  Perhaps (and this is my opinion) is an example of regression, this means that they resumed their oldest species characteristics. As is the case of flightless birds also reduce its wings.

Instead, it was her hind legs which facilitated the classification of this new species, the family Dromaeosauridae or "corridors lizards." By this I mean that was a fast runner Austroraptor, who had strong back legs and he used to hunt their prey.

The Austroraptor lived 70 million years in the late Cretaceous period in what is now South America..

Xiongguanlong, the ancestor of T.Rex


Xiongguanlong, the dragon of Jiayuguan (a city in China) is of utmost importance if we are to understand the appearance on earth Jurassic was the best known of all dinosaurs: Tyrannosaurus rex.

Its dimensions are not overly large jaw crusher or lacked teeth 30 cm long (1,2 ft) but its evolutionary features makes it worth being described as other lucky animals in this blog. Seriously, any prehistoric animal lover should know about this dinosaur.

The Xiongguanlong measured about 6 meters long and nearly 2 meters tall (7 ft), weighing around 300 kg (660 lb) the T.Rex was over twice and weighed 30 times more). His skull was about 50 cm (1,65 ft) long and the snout was long and thin that the T.Rex, more adapted to cut meat to crush bones. But I began to have those morphological features of Tyrannosaurus rex:



A box-shaped skull.
Reinforced temple bones to support the jaw muscles.
A strong spine that holds a large head.
Reduced forelimbs.
A predator might be terrible in its time but was not the biggest nor feared, did not reach the level of predator.



This Tyrannosauroidea theropod dinosaur lived in the Cretaceous between 125 and 100 million years. Keep in mind that most of the family lived in the Cretaceous Tyrannosauroidea ... not in the Jurassic as the movie suggests: Jurassic Park.

And for that matter, so as not to cause further confusion and this time for my culpa.Que the Xiongguanlong is the ancestor of T.Rex, does not mean it's necessarily the direct ancestor or the t. rex is the offspring following, but is useful in determining the overall pattern of evolution tyrannosaurid, is like knowing discovered a missing link in the evolution of T.Rex.


Last image taken from http://ca.bestpicturesof.com/paleoart
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