Showing posts with label Eocene. Show all posts
Showing posts with label Eocene. Show all posts

Proborhyaena gigantea o marsupial Bear.

Image from http://vice12345.deviantart.com/

Until recently, the largest marsupial carnivore position was occupied by the Lion carnifex marsupial or Thylacoleo reaching measures similar to those of a lioness taking anabolic. But the new number one, the largest carnivorous marsupial, is now the marsupial Bear  or Proborhyaena gigantea. An animal that if we compared the marsupial lion with a lioness; we can compare the marsupial Bear with a grizzly bear ... perhaps hence the name ... (although his jaw broken bones as the hyena, that is also related to its name).

The Proborhyena could weigh up to 1100 lb (500 kg) and 10,5 ft. (3.5 meters) long, it was not very agile, but it was quick and short but explosive career, typical of large and heavy hunters. It was a carnivore with a peculiar teeth: its fangs were projected forward and also would not stop growing. This is complemented with robust skull, 60 cm long, and a powerful and muscular neck. So it is easy to imagine that when the marsupial bear biting their prey hardly escaped. It was like a pittbull but 40 times bigger.

Image from http://other-worlds.ucoz.ru/

Although some experts believe that usually, this prehistoric predator rather than hunt, began to steal prey from other predators (size permitting). And thanks to the wear of the teeth, experts have concluded that it was dedicated to crushing bones to eat: from animals hunted either carrion than it could take. The denture reminds Tasmanian devils now living today.


Taxonomically, is related to the Thylacosmilus, which we'll talk another day. It lived from the Eocene to the Oligocene in South America.

From Miacis to the hyena.


A few days ago, I was watching the documentary typical of Africa, with its eternal battles between lions and hyenas, when something caught my attention. Early in the documentary, the narrator describing for the umpteenth time the hyenas, he said these were animals that were closer, evolutionarily speaking, a cat than a dog. I found it very funny because hyenas are very similar to dogs, even as they live in herds, ... that's when I started researching, from the beginning (or almost).

We talked of Miacis, the "animal mother", the ancestor of both dogs and cats (both as feliforms Caniformes. Following the storyline, we find gender Prionodon a split where the two genera of felids (where is the Smilodon or saber-toothed tiger and) and barbourofélidos, coming at last to viverrids (the picture above). This name is very important, viverrids developed at the end of the Eocene and they are the ancestors of hyenas and genets (Hyaenidae, Herpestidae, Eupleridae).
I imagine that no need to explain the differences between  Caniformia and Feliformia , shaped like a dog or cat shaped, with long snouts and claws fixed or short snouts and retractable claws ... but really, the peculiarity that differentiates these two groups is that the auditory bullae have their feliforms (bony capsules enclosing the middle and inner ear). This is a key to the diagnosis in the classification of species as Feliforme versus Caniforme. In the auditory bullae are feliforms dual chamber composed of two bones joined by a partition. The Caniformes has a single chamber or partially divided auditory bullae, composed of a single bone.

So it is true that the hyena (like all such) come from Miacis, and that is nearer to a big cat than a wolf. Although it is true that is nearer to a genet, a ferret or a tiger. Certainly within the family Hyaenidae we can also find the Hyena giant extinct.

The appearance of the viverrids was like a genet but more slender, had the sharp nose, long neck, tail as long as the rest of the body and dentition hipercarnívora (carnassial teeth, which cut the flesh the way scissors) which is not known is if your hair was streaked, spotted or brown uniform color. It lived in the Eocene and the two species are present linsang striped and spotted linsang.

I present a video of one of a genet, a representative living with an appearance similar to the first Feliformia  ... (precursors of the hyenas, cats, tigers or genets and weasels), perhaps this is greater.

Ambulocetus.



One of the most curious of the fascinating world of evolution is the change that antique land mammals staged to enter a world of water in seas and oceans, and that over time, evolved and became what is now the animal in the world: the blue whale.

The mammal most representative of the change of land to water is the Ambulocetus (Ambulocetus natans) which together with others of the same genus shows how did this peculiar evolution.

This animal was baptized thoroughly. Your name (Ambulocetus) literally means "walking whale." And it was called so because it has traits of cetaceans. For example: it has no external ears, but special ones like whales, and also had some adaptation in the nose that kept eating even submerged, not swallow water.

Ambulocetus was no more than three meters, and having no external ear, is thought to be similar to hunting crocodiles. This animal was receiving at the soft part of his body vibration of animals came to drink water or other pass you by.

Instead, it swam like a crocodile, but rather as a whale or an otter, that is, moving the vertical tail and wavy. Moreover, not walk out of the water like this, their legs were straight, like those of a grizzly bear.

This prehistoric animal, half way between terrestrial and aquatic mammals, lived 50 million years ago (middle Eocene) in what is now Pakistan, which once stood in the Indian Ocean.

This video is in French (I have not found anything better), but it looks good.



Moeritherium, the ancestor of the elephant.


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.



Hoplophoneus



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"



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.

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