Norian

The Norian is a division of the Triassic geological period. It has the rank of an age (geochronology) or stage (chronostratigraphy). The Norian lasted from ~228 to ~208.5 million years ago.^[1] It was preceded by the Carnian and succeeded by the Rhaetian.^[2]

Stratigraphic definitions

The Norian was named after the Noric Alps in Austria. The stage was introduced into scientific literature by Austrian geologist Edmund Mojsisovics von Mojsvar in 1869.

The Norian stage begins at the base of the ammonite biozones of Klamathites macrolobatus and Stikinoceras kerri, and at the base of the conodont biozones of Metapolygnathus communisti and Metapolygnathus primitius. A global reference profile for the base (a GSSP) had in 2009 not yet been appointed.

The top of the Norian (the base of the Rhaetian) is at the first appearance of ammonite species Cochloceras amoenum. The base of the Rheatian is also close to the first appearance of conodont species Misikella spp. and Epigondolella mosheri and the radiolarid species Proparvicingula moniliformis.

In the Tethys domain, the Norian stage contains six ammonite biozones:

• zone of Halorites macer
• zone of Himavatites hogarti
• zone of Cyrtopleurites bicrenatus
• zone of Juvavites magnus
• zone of Malayites paulckei
• zone of Guembelites jandianus

Palaeontology

• Synapsids
• Aetosaurs
• Dicynodonts
• Phytosaurs

Dinosaurs

Dinosaurs of the Norian
Taxa	Presence	Location	Description	Images
Agnosphitys	208 Ma	Avon, England	A disputed dinosaur known from an ilium, maxilla, astragalus, and humerus (it could be a chimera). Agnosphitys lies close to the ancestry of dinosaurs, although exactly where is disputed by researchers. Some consider it a saurischian close to the beginnings of dinosaur evolution, while others consider it a non-dinosaurian dinosauromorph.	Agnosphitys Coelophysis Eocursor Liliensternus Plateosaurus Thecodontosaurus
Coelophysis	Carnian to Norian	Chinle Formation, New Mexico, USA
Eocursor	210 Ma	South Africa	A swift-running basal ornithischian that has the most complete known remains from any Triassic ornithischian, shedding new light on the origin of this group. One of the earliest known ornithischians, it sheds some light on early dinosaur relationships because early dinosaurs are known from mostly incomplete skeletons. Eocursor is known from partial skeletal elements, including skull fragments, spinal elements, pelvis, long leg bones, and unusually large grasping hands.
Liliensternus	228-201.3 Ma, Norian to Rhaetian	Trossingen Formation, Thuringia, Germany	A coelophysoid that is the best represented Triassic theropod from Europe and one of the largest known.
Plateosaurus	214-204 Ma, Carnian to Norian	Trossingen Formation, Bavaria, Germany
Thecodontosaurus	Norian to Rhaetian

†Pterosaurs

Pterosaurs of the Norian
Taxa	Presence	Location	Description	Images
Eudimorphodon				Eudimorphodon Peteinosaurus Preondactylus
Peteinosaurus
Preondactylus

Crocodylomorphs

Crocodylomorphs of the Norian
Taxa	Presence	Location	Description	Images
Saltoposuchus				Saltoposuchus

†Ichthyosaurs

Ichthyosaurs of the Norian
Taxa	Presence	Location	Description	Images
Shonisaurus Shonisaurus popularis		Nevada, USA		Shonisaurus

†Dinosauromorphs (non-dinosaurian)

†Non-dinosaurian dinosauromorphs of the Norian
Taxa	Presence	Location	Description	Images
Dromomeron				Dromomeron
Eucoelophysis		New Mexico

†Placodonts

Placodonts of the Norian
Taxa	Presence	Location	Description	Images
Psephoderma				Psephoderma

†Crurotarsans (non-crocodylomorph)

†Non-crocodylomorph Crurotarsans of the Carnian
Taxa	Presence	Location	Description	Images
Basutodon		Lesotho		Teratosaurus
Teratosaurus

Mammalia

Mammalia[3] of the Carnian
Taxa	Presence	Location	Description	Images
Eozostrodon				Morganucodon
Kuehneotherium	Norian to Sinemurian	Greenland and Western Europe	A Late Triassic-Early Jurassic symmetrodontan.
Morganucodon
Sinocodon

†Ammonites

• Acanthinites

References

Notes

Literature

• Brack, P.; Rieber, H.; Nicora, A. & Mundil, R.; 2005: The Global boundary Stratotype Section and Point (GSSP) of the Ladinian Stage (Middle Triassic) at Bagolino (Southern Alps, Northern Italy) and its implications for the Triassic time scale, Episodes 28(4), pp. 233–244.
• Gradstein, F.M.; Ogg, J.G. & Smith, A.G.; 2004: A Geologic Time Scale 2004, Cambridge University Press.
• Kielan-Jaworowska, Z.; Cifelli, R. L.; Luo, Zhe-Xi; 2004: Mammals from the Age of Dinosaurs, Columbia University Press.
• Martz, J.W.; 2008: Lithostratigraphy, chemostratigraphy, and vertebrate biostratigraphy of the Dockum Group (Upper Triassic), of southern Garza County, West Texas, Doctoral Dissertation, Texas Tech.

External links

• GeoWhen Database - Norian
• Upper Triassic timescale, at the website of the subcommission for stratigraphic information of the ICS
• Norges Network of offshore records of geology and stratigraphy: Stratigraphic charts for the Triassic, and