In the geologic timescale, the Valanginian is an age or stage of the Early or Lower Cretaceous. It spans between 140.2 ± 3.0 Ma and 136.4 ± 2.0 Ma (million years ago). The Valanginian stage succeeds the Berriasian stage of the Lower Cretaceous and precedes the Hauterivian stage of the Lower Cretaceous.[1]
[edit] Stratigraphic definitions
The Valanginian was first described and named by Édouard Desor in 1853. It is named after Valangin, a small town north of Neuchâtel in the Jura Mountains of Switzerland.
The base of the Valanginian is at the first appearance of calpionellid species Calpionellites darderi in the stratigraphic column. A global reference section (a GSSP) had in 2009 not yet been appointed.
The top of the Valanginian (the base of the Hauterivian) is at the first appearance of the ammonite genus Acanthodiscus.
[edit] Subdivision
The Valanginian is often subdivided in Lower and Upper substages. The Upper substage begins at the first appearance of ammonite species Saynoceras verrucosum and the major marine transgression Va3.
In the Tethys domain, the Valanginian stage contains five ammonite biozones:
[edit] Palaeontology
[edit] †Ankylosaurs
Ankylosauria of the Valanginian |
Taxa |
Presence |
Location |
Description |
Images |
|
|
|
|
|
Birds of the Valanginian |
Taxa |
Presence |
Location |
Description |
Images |
|
|
|
|
|
|
|
|
|
[edit] Crocodylomorphs
Crocodylomorphs of the Valanginian |
Taxa |
Presence |
Location |
Description |
Images |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
[edit] †Ornithopods
Ornithopoda of the Valanginian |
Taxa |
Presence |
Location |
Description |
Images |
|
|
Australia |
May be a chimera based on multiple species of ornithopods. |
|
|
|
Europe, North America |
|
|
|
Cape Province, South Africa |
Generally considered nomen dubium, it classified as a genus similar to Dryosaurus, i.e. an iguanodont. |
|
|
Lanzhou, Gansu, China |
Notable for its "astonishingly huge teeth", among the largest for any herbivorous creature ever, which indicate it is an iguanodont. The mandible, longer than one meter, suggests very large size for the animal. |
|
|
Isle of Wight, England; Niger, Africa |
A dryosaurid |
[edit] †Pterosaurs
[edit] †Sauropods
Sauropods of the Valanginian |
Taxa |
Presence |
Location |
Description |
Images |
|
|
|
|
|
|
|
|
|
[edit] †Stegosaurs
Stegosaurs of the Valanginian |
Taxa |
Presence |
Location |
Description |
Images |
|
|
|
|
|
|
|
|
|
|
|
|
|
[edit] †Theropods (non-avian)
Non-Avian Theropods of the Valanginian |
Taxa |
Presence |
Location |
Description |
Images |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
[edit] References
- ^ See Gradstein et al. (2004) for a detailed geologic timescale
- ^ a b c d e f g h Dating uncertain.
- ^ a b Only known from this stage.
[edit] Literature
[edit] External links
|
|
|
|
|
|
In horizontal bars are eras; in left column are periods; right column: bold are epochs; not bold not italic are ages; italic are chrons:
|
|
|
|
|
|
|
|
kya = thousands years ago. Mya = millions years ago. * Not officially recognized by the I.C.S.
|
|
|
|
|
|