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Canids, where did they came from?

The canines, originated more than 40 million years ago (far before mankind) by a group of archaic carnivores, the “Miacis”. The Miacis appeared in the late Paleocene (ca. 65 to 42 million years ago).  Among them, the Miacis Cognitus was the only truly carnivorous and can be considered as the ancestor of modern carnivores. The Miacis had five fingers and size of a weasel (~ 30 cm).

Miacis
The “Miacis” had 44 teeth and the “carnassials” teeth, consisting of the fourthupper premolar and first molar.

The “Miacis” had long and slender bodies. The hind was longer than the front, the retractable claws allowed them to climb trees. The brain mass was quite large relative to the body. Canines originated in North America where they remained confined until the late Miocene (about 7-8 million years ago) when crossed the Bering Strait to reach Europe. With the formation of the isthmus of Panama, about 3 million years ago, arrived in South America.

Canidae are in the Order of Carnivores, order that includes the families of Ursida (bears), Racoons (raccoons) Mustelidae (skunks) and Pinnipeds (sea lions). The evolutionary history of canids consists of 3 successive radiations that allowed the different subfamilies to occupy an increasing number of ecological niches.

The sub-clade HESPEROCYONINAE is the largest and included 28 species. The oldest animal belonging to this subfamily was Hesperocion which appeared in the late Eocene (40 to 37 million years ago). The last species of this subfamiglia is “Osbornodon Frick”, extincted in the Miocene (15 million years ago). The subfamily BOROPHAGINAE appears in the late Oligocene that ends with the Archaeocyon, after the beginning of the Pleistocene, reached its peak and the number of species as ecological niches occupied mid-Miocene, with omnivores forms.

The first recognized member belonging to the subfamily CANINAE is Leptocyon. First appeared in the Oligocene (30 million years ago) and survived until the late Miocene (24 to 12 million years ago) when there was the evolutionary radiation that gave rise to Vulpes. In the middle Miocene (9-12 million years ago) appeared the Eucyon, a jackal-type canide that has a very developed frontal sinus. At the end of the Miocene appears in Europe and in Pliocene appears in Asia.

The Canis clade appears on the border between Miocene and Pliocene, about 5-6 million years ago in North America and then passed Eurasia. The coyote (Canis latrans), differs from the trend evolution of the wolf about 2 million years ago. The wild dog (Lycaon pictus) appears in Europe and Africa 1.5 million years ago. The first gray wolves the same as modern appear in Europe about 700,000 years ago.

 

In the next posts I’ll talk about the several Canis Lupus subclades =)

Aaaaaaaaaauuuuuuuuuuuuuuuuuuuuuuuhhhhhhhh

Anúncios

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