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Age (Ma))
Quaternary Pleistocene Gelasian younger
Neogene Pliocene Piacenzian 3.600-2.58
Zanclean 5.333-3.600
Miocene Messinian 7.246-5.333
Tortonian 11.62-7.246
Serravallian 13.82-11.62
Langhian 15.97-13.82
Burdigalian 20.44-15.97
Aquitanian 23.03-20.44
Paleogene Oligocene Chattian older
Subdivision of the Neogene Period
according to the IUGS, [v2014/02].

The Miocene /ˈmɵsn/ (symbol MI[1]) is the first geological epoch of the Neogene period and extends from about 23.03 to 5.332 million years ago (Ma). The Miocene was named by Sir Charles Lyell. Its name comes from the Greek words μείων (meiōn, “less”) and καινός (kainos, “new”)[2] and means "less recent" because it has 18% fewer modern sea invertebrates than the Pliocene. The Miocene follows the Oligocene epoch and is followed by the Pliocene epoch.

The earth went from the Oligocene through the Miocene and into the Pliocene as it cooled into a series of ice ages. The Miocene boundaries are not marked by a single distinct global event but consist rather of regional boundaries between the warmer Oligocene and the cooler Pliocene.

The apes arose and diversified during the Miocene epoch, becoming widespread in the Old World. In fact, by the end of this epoch, the ancestors of humans had split away from the ancestors of the chimpanzees to follow their own evolutionary path. As in the Oligocene before it, grasslands continued to expand and forests to dwindle in extent. In the Miocene seas, kelp forests made their first appearance and soon became one of Earth's most productive ecosystems. [3] The plants and animals of the Miocene were fairly modern. Mammals and birds were well-established. Whales, seals, and kelp spread. The Miocene epoch is of particular interest to geologists and palaeoclimatologists as major phases of Himalayan uplift had occurred during the Miocene epoch affecting monsoonal patterns in Asia, which were interlinked with glaciations in the northern hemisphere.[4]


The Miocene faunal stages from youngest to oldest are typically named according to the International Commission on Stratigraphy:[5]

Messinian (7.246–5.332 Ma)
Tortonian (11.608–7.246 Ma)
Serravallian (13.65–11.608 Ma)
Langhian (15.97–13.65 Ma)
Burdigalian (20.43–15.97 Ma)
Aquitanian (23.03–20.43 Ma)

These subdivisions within the Miocene are defined by the relative abundance of different species of calcareous nanofossils (calcite platelets shed by brown single-celled algae) and foraminifera (single-celled protists with diagnostic shells). Two subdivisions each form the Early, Middle and Late Miocene. Regionally, other systems are used. These ages often extend across the ICS epoch boundary into the Pliocene and Oligocene.













The coevolution of gritty, fibrous, fire-tolerant grasses and long-legged gregarious ungulates with high-crowned teeth, led to a major expansion of grass-grazer ecosystems, with roaming herds of large, swift grazers pursued by predators across broad sweeps of open grasslands, displacing desert, woodland, and browsers. The higher organic content and water retention of the deeper and richer grassland soils, with long term burial of carbon in sediments, produced a carbon and water vapor sink. This, combined with higher surface albedo and lower evapotranspiration of grassland, contributed to a cooler, drier climate.[7] C4 grasses, which are able to assimilate carbon dioxide and water more efficiently than C3 grasses, expanded to become ecologically significant near the end of the Miocene between 6 and 7 million years ago.[8] The expansion of grasslands and radiations among terrestrial herbivores correlates to fluctuations in CO2.[9]





In the Early Miocene, several Oligocene groups were still diverse, including nimravids, entelodonts, and three-toed horses. Like in the previous Oligocene epoch, oreodonts were still diverse, only to disappear in the earliest Pliocene. During the later Miocene mammals were more modern, with easily recognizable dogs, bears, raccoons, horses, beaver, deer, camels, and whales, along with now extinct groups like borophagine dogs, gomphotheres, three-toed horses, and semi-aquatic and hornless rhinos like Teleoceras and Aphelops. Islands began to form between South and North America in the Late Miocene, allowing ground sloths like Thinobadistes to island-hop to North America. The expansion of silica-rich C4 grasses led to worldwide extinctions of herbivorous species without high-crowned teeth.[11]

Miocene fauna of North America




Cetaceans attained their greatest diversity during the Miocene,[14] with over 20 recognized genera in comparison to only six living genera.[15] This diversification correlates with emergence of gigantic macro-predators such as megatoothed sharks and raptorial sperm whales.[16] Prominent examples are C. megalodon and L. melvillei.[16] Other notable large sharks were C. chubutensis, Isurus hastalis, and Hemipristis serra.

Crocodilians also showed signs of diversification during Miocene. The largest form among them was a gigantic caiman Purussaurus which inhabited South America.[17] Another gigantic form was a false gharial Rhamphosuchus, which inhabited modern age India. A strange form Mourasuchus also thrived alongside Purussaurus. This species developed a specialized filter-feeding mechanism, and it likely preyed upon small fauna despite its gigantic size.

The pinnipeds, which appeared near the end of the Oligocene, became more aquatic. Prominent genus was Allodesmus.[18] A ferocious walrus, Pelagiarctos may have preyed upon other species of pinnipeds including Allodesmus.





Middle Miocene disruption[edit]


See also[edit]


  2. ^ "Miocene". Online Etymology Dictionary. Retrieved July 2013. 
  3. ^ http://www.bbc.co.uk/nature/history_of_the_earth/Miocene
  4. ^ An Zhisheng, John E. Kutzbach, Warren L. Prell & Stephen C. Porter (2001). "Evolution of Asian monsoons and phased uplift of the Himalaya Tibetan plateau since Late Miocene times". Nature 411 (6833): 62–66. doi:10.1038/35075035. 
  6. ^ Attorre, F.; Francesconi, F.; Taleb, N.; Scholte, P.; Saed, A.; Alfo, M.; Bruno, F. (2007). "Will dragonblood survive the next period of climate change? Current and future potential distribution of Dracaena cinnabari (Socotra, Yemen)". Biological Conservation 138 (3–4): 430. doi:10.1016/j.biocon.2007.05.009.  edit
  7. ^ Retallack, Gregory (2001). "Cenozoic Expansion of Grasslands and Climatic Cooling". The Journal of Geology (University of Chicago Press) 109 (4): 407–426. Bibcode:2001JG....109..407R. doi:10.1086/320791. 
  10. ^ Susanne S. Renner (2011). "Living fossil younger than thought". Science 334 (6057): 766–767. Bibcode:2011Sci...334..766R. doi:10.1126/science.1214649. PMID 22076366. 
  13. ^ Begun, David. "Fossil Record of Miocene Hominoids". University of Toronto. Retrieved July 11, 2014. 
  16. ^ a b Olivier Lambert, Giovanni Bianucci, Klaas Post, Christian de Muizon, Rodolfo Salas-Gismondi, Mario Urbina & Jelle Reumer (2010). "The giant bite of a new raptorial sperm whale from the Miocene epoch of Peru". Nature 466 (7302): 105–108. Bibcode:2010Natur.466..105L. doi:10.1038/nature09067. PMID 20596020. 
  17. ^ Orangel A. Aguilera, Douglas Riff & Jean Bocquentin-Villanueva (2006). "A new giant Pusussaurus (Crocodyliformes, Alligatoridae) from the Upper Miocene Urumaco Formation, Venezuela". Journal of Systematic Palaeontology 4 (3): 221–232. doi:10.1017/S147720190600188X. 
  18. ^ Lawrence G. Barnes & Kiyoharu Hirota (1994). "Miocene pinnipeds of the otariid subfamily Allodesminae in the North Pacific Ocean: systematics and relationships". Island Arc 3 (4): 329–360. doi:10.1111/j.1440-1738.1994.tb00119.x. 
  19. ^ Kenneth G. Miller & Richard G. Fairbanks (1983). "Evidence for Oligocene−Middle Miocene abyssal circulation changes in the western North Atlantic". Nature 306 (5940): 250–253. Bibcode:1983Natur.306..250M. doi:10.1038/306250a0. 

Further reading[edit]

External links[edit]

Neogene Period
Miocene Pliocene
Aquitanian |Burdigalian
Langhian | Serravallian
Tortonian | Messinian
Zanclean | Piacenzian