Serravallian in the context of "South American Land Mammal Ages"

The Tortonian is in the geologic time scale an age or stage of the late Miocene that spans the time between 11.608 ± 0.005 Ma and 7.246 ± 0.005 Ma (million years ago). It follows the Serravallian and is followed by the Messinian.

The Tortonian roughly overlaps with the regional Pannonian Stage of the Paratethys timescale of Central Europe. It also overlaps the upper Astaracian, Vallesian and lower Turolian European land mammal ages, the upper Clarendonian and lower Hemphillian North American land mammal ages and the upper Chasicoan and lower Huayquerian South American land mammal ages.

The Astaracian age is a period of geologic time (16 to 11.6 Ma), equivalent with the Middle Miocene and used more specifically with European Land Mammal Ages. It precedes the Vallesian age and follows the Orleanian age. The Astaracian overlaps the Langhian and Serravallian ages.

During the Late Orleanian and Astaracian (17 to 10.7 Ma), oscillating sea levels resulted in a succession of palaeogeographic changes in the Eastern Mediterranean; the opening and closing of the Tethys seaway resulted in temporary land-bridges between Africa and Eurasia. Three short periods of faunal migrations between the continents can be distinguished:

The Clarendonian North American Stage on the geologic timescale is the North American faunal stage according to the North American Land Mammal Ages chronology (NALMA), typically set from 13,600,000 to 10,300,000 years BP, a period of 3.3 million years.

It is usually considered to overlap the Serravallian age of the Middle Miocene and the Tortonian age of the Late Miocene. The Clarendonian is preceded by the Barstovian and followed by the Hemphillian NALMA stages.

The Middle Miocene is a sub-epoch of the Miocene epoch made up of two stages: the Langhian and Serravallian stages. The Middle Miocene is preceded by the Early Miocene, and followed by the Late Miocene.

The sub-epoch lasted from 15.97 ± 0.05 Ma (million years ago) to 11.608 ± 0.005 Ma. During this period, a sharp drop in global temperatures took place. This event is known as the Middle Miocene Climatic Transition.