Early Miocene
Encyclopedia
The Early Miocene is a sub-epoch of the Miocene
Epoch
made up of two stages
: the Aquitanian
and Burdigalian
stages.
The sub-epoch lasted from 23.03 ± 0.05 Ma to 15.97 ± 0.05 Ma (million years ago). It was preceded by the Oligocene
epoch. As the climate started to get cooler, the landscape started to change. New mammals evolved to replace the extinct animals of the Oligocene epoch.The first members of the hyena
and weasel
family started to evolve to replace the extinct Hyaenodon
, entelodont
s and bear-dogs. The chalicothere
s survived the Oligocene epoch. A new genus of entelodont called Daeodon evolved in order to adapt to the new habitats and hunt the new prey animals of the Early Miocene epoch; it quickly became the top predator of North America
. But it became extinct due to competition
from Amphicyon
, a newcomer from Eurasia
. Amphicyon bested Daeodon because the bear-dog's larger brain, sharper teeth and longer legs built for longer chases helped it to overcome its prey.
Miocene
The Miocene is a geological epoch of the Neogene Period and extends from about . The Miocene was named by Sir Charles Lyell. Its name comes from the Greek words and and means "less recent" because it has 18% fewer modern sea invertebrates than the Pliocene. The Miocene follows the Oligocene...
Epoch
Epoch (geology)
An epoch is a subdivision of the geologic timescale based on rock layering. In order, the higher subdivisions are periods, eras and eons. We are currently living in the Holocene epoch...
made up of two stages
Faunal stage
In chronostratigraphy, a stage is a succession of rock strata laid down in a single age on the geologic timescale, which usually represents millions of years of deposition. A given stage of rock and the corresponding age of time will by convention have the same name, and the same boundaries.Rock...
: the Aquitanian
Aquitanian age
The Aquitanian is, in the ICS' geologic timescale, the oldest age or lowest stage in the Miocene. It spans the time between 23.03 ± 0.05 Ma and 20.43 ± 0.05 Ma and is a dry, cooling period...
and Burdigalian
Burdigalian
The Burdigalian is, in the geologic timescale, an age or stage in the early Miocene. It spans the time between 20.43 ± 0.05 Ma and 15.97 ± 0.05 Ma...
stages.
The sub-epoch lasted from 23.03 ± 0.05 Ma to 15.97 ± 0.05 Ma (million years ago). It was preceded by the Oligocene
Oligocene
The Oligocene is a geologic epoch of the Paleogene Period and extends from about 34 million to 23 million years before the present . As with other older geologic periods, the rock beds that define the period are well identified but the exact dates of the start and end of the period are slightly...
epoch. As the climate started to get cooler, the landscape started to change. New mammals evolved to replace the extinct animals of the Oligocene epoch.The first members of the hyena
Hyena
Hyenas or Hyaenas are the animals of the family Hyaenidae of suborder feliforms of the Carnivora. It is the fourth smallest biological family in the Carnivora , and one of the smallest in the mammalia...
and weasel
Weasel
Weasels are mammals forming the genus Mustela of the Mustelidae family. They are small, active predators, long and slender with short legs....
family started to evolve to replace the extinct Hyaenodon
Hyaenodon
Hyaenodon is an extinct genus of Hyaenodonts, a group of carnivorous creodonts of the family Hyaenodontidae endemic to all continents except South America, Australia and Antarctica, living from 42—15.9 mya, existing for approximately .-Morphology:Some species of this genus were amongst the largest...
, entelodont
Entelodont
Entelodonts, sometimes nicknamed hell pigs or terminator pigs, is an extinct family of pig-like omnivores endemic to forests and plains of North America, Europe, and Asia from the middle Eocene to early Miocene epochs , existing for approximately .-Taxonomy:Entelodontidae was named by Richard...
s and bear-dogs. The chalicothere
Chalicothere
Chalicotheres were a group of herbivorous, odd-toed ungulate mammals spread throughout North America, Europe, Asia, and Africa during the Early Eocene to Early Pleistocene subepochs living from 55.8 mya—781,000 years ago, existing for approximately .They evolved around 40 million years ago from...
s survived the Oligocene epoch. A new genus of entelodont called Daeodon evolved in order to adapt to the new habitats and hunt the new prey animals of the Early Miocene epoch; it quickly became the top predator of North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
. But it became extinct due to competition
Competition
Competition is a contest between individuals, groups, animals, etc. for territory, a niche, or a location of resources. It arises whenever two and only two strive for a goal which cannot be shared. Competition occurs naturally between living organisms which co-exist in the same environment. For...
from Amphicyon
Amphicyon
Amphicyon is an extinct genus of large carnivorous bone-crushing mammals, known as bear-dogs, of the family Amphicyonidae, subfamily Amphicyoninae, from the Aquitanian Epoch until the Tortonian...
, a newcomer from Eurasia
Eurasia
Eurasia is a continent or supercontinent comprising the traditional continents of Europe and Asia ; covering about 52,990,000 km2 or about 10.6% of the Earth's surface located primarily in the eastern and northern hemispheres...
. Amphicyon bested Daeodon because the bear-dog's larger brain, sharper teeth and longer legs built for longer chases helped it to overcome its prey.