Orleanian

The Orleanian age is a period of geologic time (MN 3–5, 20 to 16 million years ago (mya)), within the Miocene and used more specifically with European Land Mammal Ages. It precedes the Astaracian age and follows the Agenian age.

At the time for Oligocene-Miocene boundary (23.8 mya), the Tethys Seaway, a deep through between the Arabian and Iranian Plates, isolated Africa from Eurasia; an isolation that lasted until the gradual closure of the Tethys at the end of MN 3 (19-18 mya), and America was connected to Asia by the Beringian landbridge. The horse-like equid Anchitherium dispersed into Asia over the latter and is known on the Iberian Peninsula from MN 3 and from Asia Minor in MN 6. It has not been found on the Balkan Peninsula, which suggests that the Balkans were isolated from Asia Minor at that time. In Western Europe, the pig-like suids Hyotherium appears in MN 1 and Xenohyus in MN 2. The hippo-like 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.