The Vallesian age is a period of
geologic time
The geologic time scale or geological time scale (GTS) is a representation of time based on the rock record of Earth. It is a system of chronological dating that uses chronostratigraphy (the process of relating strata to time) and geochronolo ...
(11.6–9.0
Ma) within the
Miocene
The Miocene ( ) is the first epoch (geology), geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and mea ...
used more specifically with
European Land Mammal Ages. It precedes the
Turolian age and follows the
Astaracian age. The so-called Vallesian Crisis resulted in the extinction of several mammalian taxa characteristic of the Middle Miocene.
The term "Vallesian" was introduced by Catalan palaeontologist
Miquel Crusafont in 1950 to mark the arrival of the
equid
Equidae (commonly known as the horse family) is the Taxonomy (biology), taxonomic Family (biology), family of Wild horse, horses and related animals, including Asinus, asses, zebra, zebras, and many extinct species known only from fossils. The fa ...
''
Hipparion'' in Europe. The remaining European palaeofaunas, however, had been around since the
Middle Miocene
The Middle Miocene is a sub-epoch of the Miocene epoch (geology), epoch made up of two Stage (stratigraphy), stages: the Langhian and Serravallian stages. The Middle Miocene is preceded by the Early Miocene.
The sub-epoch lasted from 15.97 ± 0. ...
, including the moschid ''
Micromeryx'' (a musk deer), the cervid ''
Euprox'', the suid ''
Listriodon'', and the felids ''
Sansanosmilus'' and ''
Pseudaelurus'', and the Aragonian-Vallesian
["Aragonian" is a Spanish term for a continental stage, roughly equivalent to the Middle Miocene or Astaracian (16–11 Ma).] boundary does not represent a major shift in the European mammalian record. In contrast, the transition between Lower and Upper Vallesian corresponds to a major biotic crisis — the demise of most Aragonian
artiodactyl
Artiodactyls are placental mammals belonging to the order Artiodactyla ( , ). Typically, they are ungulates which bear weight equally on two (an even number) of their five toes (the third and fourth, often in the form of a hoof). The other t ...
s, including the antelope ''
Protragocerus'', the bovid ''
Miotragocerus'', ''Listriodon'', and the suids ''
Hyotherium'' and ''
Parachleusastochoerus''. The crisis also affected rodents such as the family
Eomyidae and most of the
cricetids and
glirids. They were replaced by species arriving from the east, Turolian in character: for example the suid ''
Schizochoerus'', the murid ''
Progonomys'', the bovids ''
Tragoportax'' and ''
Graecoryx'', the hyaenid ''
Adcrocuta'', the felid ''
Paramachairodus'', and the suid ''
Microstonyx''.
The Vallesian was a crucial period for the evolution of the European terrestrial fauna. During the Middle Miocene, the highly diversified mammalian fauna of the European forests were replaced by the faunas of the Late Miocene, adapted to a dry climate and to an open terrain. The beginning of the period is marked by the appearance and dispersal of the early horse ''
Hipparion'' throughout Eurasia. The so-called Vallesian Crisis resulted in the extinction of several mammalian taxa characteristic of the Middle Miocene. The end of the Vallesian, and the beginning of the Turolian, brought the extinction in the west of faunas dominated by the
bovids and
giraffids characteristic of the so-called sub-
Paratethyan or Greek-Iranian province.
Notes
References
{{Neogene Footer
Miocene