System/
Period		 Series/
Epoch		 Stage/
Age		 Age (Ma)
Quaternary Pleistocene Gelasian younger
Neogene Pliocene Piacenzian 2.58 3.600
Zanclean 3.600 5.333
Miocene Messinian 5.333 7.246
Tortonian 7.246 11.63
Serravallian 11.63 13.82
Langhian 13.82 15.97
Burdigalian 15.97 20.44
Aquitanian 20.44 23.03
Paleogene Oligocene Chattian older
Subdivision of the Neogene Period
according to the ICS, as of 2017.[1]

The Early Miocene (also known as Lower Miocene) is a sub-epoch of the Miocene Epoch made up of two stages: the Aquitanian and Burdigalian stages.[2][3]

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, entelodonts and bear-dogs. The chalicotheres 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.

References

  1. ↑ "ICS Timescale Chart". www.stratigraphy.org.
  2. ↑ Lucas, Spencer G.; Blodgett, Robert B.; Lichtig, Asher J.; Hunt, Adrian P. (2022-08-02). FOSSIL RECORD 8. New Mexico Museum of Natural History and Science. pp. 400–401.
  3. ↑ Raffery, John, ed. (2010-08-15). The Cenozoic Era: Age of Mammals. The Rosen Publishing Group, Inc. pp. 104–105. ISBN 978-1-61530-144-7.


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