Orleanian

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The Orleanian age is a period of

European Land Mammal Ages. It precedes the Astaracian age and follows the Agenian age.[1]

Agenian-Early Orleanian migration 23.8 to 18 mya

At the time for

anthracothere Brachyodus appears in Western Europe in MN 3 and, while the MN 1-3 fauna is rare in the Eastern Mediterranean, also in Greece from around MN 3-4. The spalacid (rodent) Debruijnia is known from Asia Minor from MN 3 and from Aliveri, Greece, from early MN 4, suggesting the presence of some kind of early connection between Asia Minor and the Balkans.[2]

Middle Orleanian migration 18 to 17 mya

The connection between Eurasia and Africa, known as the "Gomphotherium land bridge", was re-established at the end of MN 3. However, temporary landbridges appears to have connected Africa to Eurasia before the final closure of the Tethys Seaway, allowing some mammals to emigrate between the landmasses. With the Balkans solidly connected to Asia Minor, the seaways to the Paratethys were closed, which transformed the shallow sea into an isolated basin with its own endemic fauna. The Gomphotherium-landbridge provided the African

hyrocoid Pliohyrax with the opportunity to emigrate to India where it is known from the end of MN 3. It has been found in Turkey from MN 6 and, as the primitive deinothere (elephant-like) Prodeinotherium is known from Lesbos, Greece, it seems likely there was a connection between the regions around 18.4 mya.[2]

Emigration occurred in both directions across the landbridge around 20.7 mya. The MN 3 fauna of

nimravid (cat) Prosansanosmilus, and rodents such as Megacricetodon, Democricetodon, Cricetodon, and Eumyarion. The subfamily Democricetodontinae appeared in Asia Minor during MN 1-2, in Africa and Asia during MN 3, in America during MN 3-4 and finally in the Balkans and Western Europe during MN 4.[2]

See also

References