MN 4 (biostratigraphy)

In biostratigraphy, MN 4 is one of the MN zones used to characterize the fossil mammal faunas of the Neogene of Europe. It is preceded by and followed by MN 5; together, these three zones form the Orleanian age of the middle Miocene. This zone starts within magnetostratigraphicchron C5Dr, at 18 million years ago, and ends within chron C5Cr, at 17.0 million years ago, although some different correlations have been proposed.

The reference locality used to correlate faunas with this zone is La Romieu (southwestern France); other localities include and Buñol in Spain, in Switzerland, and in Germany, in Poland, and Aliveri in Greece.

In this zone, the common muroid rodent immigrates into Europe from Asia, followed shortly after by three other muroids: , , and . , which later also reaches western Europe, is only present in Greece in MN 4 in Europe. The archaic muroid last appears in MN 4, as does , a member of the extinct rodent family Eomyidae. The dormouseGlirulus, which occurs in older deposits in Turkey, first appears in Europe; this genus contains a single living species, the Japanese dormouse (Glirulus japonicus).

The proboscidean genera—members of the group that includes the elephants—Archaeobelodon and Prodeinotherium first appear in Europe. The rhinoceros Diaceratherium last appears in MN 4 and five other rhinoceros genera, Plesiaceratherium, Brachypotherium, Lartetotherium, Gaindatherium, and Hispanotherium, make their first appearance. , a member of the related extinct family Chalicotheriidae, migrates into Europe during MN 4. Several artiodactyls, such as the pig Bunolistriodon, the tragulidDorcatherium, the deer-like Lagomeryx, the bovid-like , and the first true bovid of Europe, Eotragus, first occur during MN 4. The last occurrence of the primitive ruminantAmphitragulus also falls in this zone. The immigrant African creodontHyainailouros occurs in Europe during MN 4. Among carnivorans, the first occurrences of the mustelid and the saber-toothed Prosansanosmilus fall in MN 4.