Showing posts with label Miacis. Show all posts
Showing posts with label Miacis. Show all posts

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.

Miacis


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

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

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

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