- Miocene Epoch
Major division of the Tertiary Period, from 23.8 to 5.3 million years ago. The extensive fossil record of terrestrial life during the Miocene provides a fairly complete picture of the development of vertebrates, especially mammals. Miocene mammals were essentially modern, and half of the known modern families are present in the Miocene record. The horse evolved, mainly in North America, and advanced primates, including apes, were present in southern Europe. Some interchange of faunas occurred in the Northern Hemisphere between the Old and New Worlds. Free communication was possible between Africa and Eurasia, but South America and Australia remained isolated.
* * *▪ geologyearliest major worldwide division of the Neogene Period (the past 23 million years) that extended from 23 million to 5.3 million years ago. It is often divided into the Early Miocene Epoch (23 million to 16 million years ago), the Middle Miocene Epoch (16 million to 11.6 million years ago), and the Late Miocene Epoch (11.6 million to 5.3 million years ago). The Miocene may also be divided into six ages and their corresponding rock stages: from oldest to youngest these ages or stages are the Aquitanian (Aquitanian Stage), Burdigalian (Burdigalian Stage), Langhian (Langhian Stage), Serravallian (Serravallian Stage), Tortonian (Tortonian Stage), and Messinian (Messinian Stage). The Miocene followed the Oligocene Epoch of the Paleogene Period and was succeeded by the Pliocene Epoch.Important Miocene deposits occur in North and South America, southern Europe, India, Mongolia, East Africa, and Pakistan. Both marine and terrestrial environments are represented in the Miocene stratigraphic record. The record of terrestrial life is extensive and varied, providing a rather complete view of the development of vertebrates (vertebrate), especially mammals (mammal).During the Miocene, land-dwelling mammals were essentially modern; many archaic groups were extinct by the end of the preceding Oligocene, and fully half of the mammalian families known today are present in the Miocene record. In the Northern Hemisphere, some interchange of faunas occurred between the Old and New Worlds. Interchange was also possible between Africa and Eurasia, but South America and Australia remained isolated. During the Miocene, horse evolution (horse) occurred mainly in North America; forms such as Parahippus, Miohippus (a form carried over from the preceding Oligocene Epoch), Anchitherium, Hypohippus, Pliohippus, and Merychippus are genera that represent great diversification and development. Also, the first dogs (dog) and bears (bear) appeared; the timing of the first emergence of the bear-dog Hemicyon occurs close to the origin of the bears. The first hyenas (hyena), springing from primitive civets (civet), appeared in the Miocene, as did the early sabre-toothed cats (sabre-toothed cat). Primitive antelope, deer, and giraffes (giraffe) appeared in Eurasia during the Miocene. Ancestors of the modern elephants (elephant), which during the preceding Oligocene seem to have been limited to Africa, appear to have spread to the Eurasian continent during the Miocene and became more diverse.In Argentina the Santa Cruz Formation of Middle Miocene time provides an excellent record of the unusual Miocene fauna of South America. marsupial carnivores, aberrant endentates (mammals resembling anteaters, armadillos, and sloths), litopterns (litoptern) (hoofed mammals similar to horses and camels), and toxodonts (mammals with long, curved incisors) are among the odd groups represented. These forms were able to evolve because of South America's isolation from other regions. The evolution of the South American monkeys (monkey) was also under way during the Miocene.By the end of the Miocene Epoch almost all the modern groups of whales (whale) had appeared, as had the early seals (seal) and walruses (walrus). Birds such as herons (heron), rails (rail), ducks (duck), eagles (eagle), hawks (hawk), crows (crow), sparrows (sparrow), pheasants (pheasant), owls (owl), and partridges (partridge) were present in Europe, where the uplifting of the Alps continued through Miocene time.The Miocene Epoch is also of great importance to primate evolution. The last primate to occur in the fossil record of North America, a tarsier-like creature, is known in the United States. Elsewhere, the higher primates, especially the apes (ape), underwent a great deal of evolution. The fossil evidence seems to indicate that advanced primates, including apes, were present in southern Europe. An early gibbon, Pliopithecus, as well as the dryopithecines (Dryopithecus), a group of advanced humanlike apes that probably represent the stock from which modern apes and humans originated, are found in Miocene rocks of Europe. The dryopithecines also are present in the Miocene of Africa, the region where humanlike forms as well as modern humans probably originated.In the oceans, the Miocene was a time of changing circulation patterns, probably due to global cooling. Patterns of oceanic nutrient distribution changed, leading to increased productivity in some regions and decreased productivity in others. The Miocene was a time of accelerated evolution among marine plankton and mollusks (mollusk), with many groups showing increases in diversity.
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Miocene epoch — noun from 25 million to 13 million years ago; appearance of grazing mammals • Syn: ↑Miocene • Instance Hypernyms: ↑epoch • Part Holonyms: ↑Tertiary, ↑Tertiary period … Useful english dictionary
Miocene — [mī′ō sēn΄, mī′əsēn΄] adj. [< Gr meiōn, less (see MINOR) + CENE] [sometimes m ] designating or of the first geologic epoch of the Neogene, characterized by the joining of what are now Africa, Arabia, and Eurasia and the development of manlike… … English World dictionary
Miocene — System Series Stage Age (Ma) Quaternary Pleistocene Gelasian younger Neogene Pliocene … Wikipedia
epoch — /ep euhk/ or, esp. Brit., /ee pok/, n. 1. a particular period of time marked by distinctive features, events, etc.: The treaty ushered in an epoch of peace and good will. 2. the beginning of a distinctive period in the history of anything: The… … Universalium
Miocene — /muy euh seen /, Geol. adj. 1. noting or pertaining to an epoch of the Tertiary Period, occurring from 25 to 10 million years ago, when grazing mammals became widespread. See table under geologic time. n. 2. the Miocene Epoch or Series. [1825 35; … Universalium
Miocene — 1. adjective Of a geologic epoch within the Neogene period from about 23 to 5.3 million years ago; marked by the drift of continents to their present position. 2. noun The Miocene epoch … Wiktionary
Miocene — Mi•o•cene [[t]ˈmaɪ əˌsin[/t]] Geol. 1) gel noting or pertaining to an epoch of the Tertiary Period, occurring from 25 million to 10 million years ago, when grazing mammals became widespread 2) gel the Miocene Epoch or Series • Etymology: 1832;… … From formal English to slang
Miocene — ► ADJECTIVE Geology ▪ relating to the fourth epoch of the Tertiary period (23.3 to 5.2 million years ago), a time when the first apes appeared. ORIGIN from Greek mei n less + kainos new … English terms dictionary
Miocene — adjective Etymology: mio (from Greek meiōn less) + cene more at meiosis Date: 1831 of, relating to, or being an epoch of the Tertiary between the Pliocene and the Oligocene or the corresponding series of rocks see geologic time table • Miocene… … New Collegiate Dictionary
Miocene — An epoch of the Tertiary Period of geologic time (approximately 5.2 to 23 million years ago) that immediately follows the Oligocene and precedes the Pliocene Epoch; also the corresponding (time stratigraphic) series of earth materials. HP … Glossary of landform and geologic terms