The Serravallian is, in the

geologic timescale 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 geochronol ...

, an

age Age or AGE may refer to: Time and its effects * Age, the amount of time someone or something has been alive or has existed ** East Asian age reckoning, an Asian system of marking age starting at 1 * Ageing or aging, the process of becoming older ...

or a stage in the middle Miocene Epoch/ Series, which spans the time between 13.82 Ma and 11.63 Ma (million years ago). The Serravallian follows the Langhian and is followed by the Tortonian. It overlaps with the middle of the Astaracian European Land Mammal Mega Zone, the upper

Barstovian The Barstovian 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 16,300,000 to 13,600,000 years BP, a period of . It is usua ...

and lower Clarendonian

North American Land Mammal Ages The North American land mammal ages (NALMA) establishes a geologic timescale for North American fauna beginning during the Late Cretaceous and continuing through to the present. These periods are referred to as ages or intervals (or stages when ref ...

and the Laventan and lower Mayoan South American Land Mammal Ages. It is also coeval with the Sarmatian and upper Badenian Stages of the

Paratethys The Paratethys sea, Paratethys ocean, Paratethys realm or just Paratethys was a large shallow inland sea that stretched from the region north of the Alps over Central Europe to the Aral Sea in Central Asia. Paratethys was peculiar due to its pa ...

time scale of Central and eastern Europe.

Definition

The Serravallian Stage was introduced in stratigraphy by the Italian geologist Lorenzo Pareto in 1865. It was named after the town of Serravalle Scrivia in northern Italy. The base of the Serravallian is at the first occurrence of fossils of the nanoplankton species '' Sphenolithus heteromorphus'' and is located in the

chronozone A chronozone or chron is a unit in chronostratigraphy, defined by events such as geomagnetic reversals (magnetozones), or based on the presence of specific fossils (biozone or biochronozone). According to the International Commission on Stratig ...

C5ABr. The official Global Boundary Stratotype Section and Point (GSSP) for the Serravallian is in the 'Ras il-Pellegrin' section, located at the 'Ras il-Pellegrin' headland in the vicinity of 'Fomm ir-Rih' Bay, SW Malta.The base of the Serravallian is represented in the field as the formation boundary between the Globigerina Limestone formation and the Blue Clay formation. The base of the Serravallian is related to the Mi3b oxygen isotope excursion marking the onset of the Middle Miocene Cooling step. The top of the Serravallian (the base of the Tortonian Stage) is at the last common appearance of calcareous nanoplanktons ''

Discoaster kugleri ''Discoaster'' is a genus of extinct star-shaped marine algae, with calcareous exoskeletons of between 5-40 μm across that are abundant as nanofossils in tropical deep-ocean deposits of Neogene age. ''Discoaster'' belongs to the haptophyte ...

'' and planktonic foram '' Globigerinoides subquadratus''. It is also associated with the short normal-polarized chronozone C5r.2n.

Paleontology

Cartilaginous fish

* Lamniformes ** Otodontidae: †'' Otodus''

Birds

Anseriformes Anseriformes is an order of birds also known as waterfowl that comprises about 180 living species of birds in three families: Anhimidae (three species of screamers), Anseranatidae (the magpie goose), and Anatidae, the largest family, which in ...

** Anatidae: ''

Clangula The long-tailed duck (''Clangula hyemalis''), formerly known as oldsquaw, is a medium-sized sea duck that breeds in the tundra and taiga regions of the arctic and winters along the northern coastlines of the Atlantic and Pacific Oceans. It is th ...

sp.''

Mammals

Primates Primates are a diverse order of mammals. They are divided into the strepsirrhines, which include the lemurs, galagos, and lorisids, and the haplorhines, which include the tarsiers and the simians (monkeys and apes, the latter including huma ...

Hominidae The Hominidae (), whose members are known as the great apes or hominids (), are a taxonomic family of primates that includes eight extant species in four genera: '' Pongo'' (the Bornean, Sumatran and Tapanuli orangutan); ''Gorilla'' (the ea ...

: †''

Anoiapithecus ''Anoiapithecus'' is an extinct ape genus thought to be closely related to ''Dryopithecus''. Both genera lived during the Miocene, approximately 12 million years ago. Fossil specimens named by Salvador Moyà-Solà are known from the deposits fr ...

''.

Reptiles

* Squamata **

Agamidae Agamidae is a family (biology), family of over 300 species of iguanian lizards indigenous to Africa, Asia, Australia, and a few in Southern Europe. Many species are commonly called dragons or dragon lizards. Overview phylogenetics, Phylogenetic ...

: '' Pogona'' and '' Diporiphora'' diverged from their last common ancestor during the Serravallian. * Crocodylomorpha **The last known sebecid, '' Barinasuchus'', goes extinct about 11.8

mya Mya may refer to: Brands and product names * Mya (program), an intelligent personal assistant created by Motorola * Mya (TV channel), an Italian Television channel * Midwest Young Artists, a comprehensive youth music program Codes * Burmese ...

. Thus ending the lineage of the notosuchians.

References

Notes

Literature

*; 2004: ''A Geologic Time Scale 2004'', Cambridge University Press. *; 1865: ''Note sur la subdivision que l'on pourrait etablir dans les terrains de l'Apennin septentrional'', Bulletin de la Société Géologique de France 2(22), p. 210-277.

External links

GeoWhen Database - SerravallianNeogene timescale
at the website of the subcommission for stratigraphic information of the ICS
Neogene timescale
at the website of the Norwegian network of offshore records of geology and stratigraphy {{Geological history, p, c *04 Miocene geochronology Geological ages