Santonian

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System/
Period
Series/
Epoch
Stage/
Age
Age (Ma)
PaleogenePaleoceneDanianyounger
CretaceousUpper/
Late
Maastrichtian66.0–72.1
Campanian72.1–83.6
Santonian83.6–86.3
Coniacian86.3–89.8
Turonian89.8–93.9
Cenomanian93.9–100.5
Lower/
Early
Albian100.5–~113.0
Aptian~113.0–~125.0
Barremian~125.0–~129.4
Hauterivian~129.4–~132.9
Valanginian~132.9–~139.8
Berriasian~139.8–~145.0
JurassicUpper/
Late
Tithonianolder
Subdivision of the Cretaceous system
according to the IUGS, as of July 2012.

The Santonian is an age in the geologic timescale or a chronostratigraphic stage. It is a subdivision of the Late Cretaceous epoch or Upper Cretaceous series. It spans the time between 85.8 ± 0.7 mya (million years ago) and 83.5 ± 0.7 mya. The Santonian is preceded by the Coniacian and is followed by the Campanian.[1]

Stratigraphic definition[edit]

The Santonian stage was established by French geologist Henri Coquand in 1857. It is named after the city of Saintes in the region of Saintonge, where the original type locality is located.

The base of the Santonian stage is defined by the appearance of the inoceramid bivalve Cladoceramus undulatoplicatus. Its top (the base of the Campanian stage) is marked by the extinction of the crinoid Marsupites testudinarius.[2] In 2009, a GSSP (official reference profile) for both base and top had not yet been appointed.

Subdivision[edit]

The Santonian is sometimes subdivided into Lower, Middle and Upper substages. In the Tethys domain the Santonian is coeval with a single ammonite biozone: that of Placenticeras polyopsis. Biostratigraphy based on inoceramids, nannoplankton or forams is more detailed.

Paleontology[edit]

†Ankylosaurs[edit]

Ankylosaurs of the Santonian
TaxaPresenceLocationDescriptionImages

Birds (avian theropods)[edit]

Birds of the Santonian
TaxaPresenceLocationDescriptionImages

Apatornis[4]

Neuquenornis[3]

Parahesperornis[4]

Patagopteryx[3]

Cartilaginous Fish[edit]

Cartilaginous Fish of the Santonian
TaxaPresenceLocationDescriptionImages
  • Hexanchus microdon
  • Notidanodon
  • Notidanoides[4]

†Ceratopsians[edit]

Ceratopsians of the Santonian
TaxaPresenceLocationDescriptionImages
Reconstruction of Udanoceratops

Crocodylomorphs[edit]

Crocodylomorphs of the Santonian
TaxaPresenceLocationDescriptionImages
Reconstruction of Notosuchus, a relative of the crocodiles

Mammals[edit]

Mammals of the Santonian
TaxaPresenceLocationDescriptionImages
  • Paracimexomys
  1. Paracimexomys magister[3]

†Ornithopods[edit]

Ornithopods of the Santonian
TaxaPresenceLocationDescriptionImages
Claosaurus
Reconstruction of Nipponosaurus, a duck-billed dinosaur

†Plesiosaurs[edit]

Plesiosauria of the Santonian
TaxaPresenceLocationDescriptionImages
Dolichorhynchops osborni from Coniacian to CampanianFort Hays Limestone, Kansas, USA
Reconstruction of Dolichorhynchops

†Pterosaurs[edit]

Pterosaurs of the Santonian
TaxaPresenceLocationDescriptionImages
Reconstruction of Bakonydraco

†Sauropods[edit]

Sauropods of the Santonian
TaxaPresenceLocationDescriptionImages

Squamates[edit]

Squamates of the Santonian
TaxaPresenceLocationDescriptionImages

Eonatator

Reconstruction of Tylosaurus, a mosasaur
  1. Madtsoia madagascariensis[4]

Pannoniasaurus

Tylosaurus

†Theropods (non-avian)[edit]

Non-avian theropods of the Santonian
TaxaPresenceLocationDescriptionImages

Achillesaurus[3]

Achillobator

Alectrosaurus

Aucasaurus[3]

Flora[edit]

Advanced dicotyledons

References[edit]

Notes[edit]

  1. ^ Gradstein et al. (2004)
  2. ^ "GeoWhen Database - Barremian". Archived from the original on 2007-10-22. Retrieved 2007-12-02. "Version 1.1.0." 
  3. ^ a b c d e f g Only known from this stage
  4. ^ a b c d e Dating uncertain

Literature[edit]

External links[edit]

Cretaceous Period
Lower/Early CretaceousUpper/Late Cretaceous
Berriasian | Valanginian | Hauterivian
Barremian| Aptian | Albian
Cenomanian | Turonian | Coniacian
Santonian |Campanian | Maastrichtian