System/
Period
Series/
Epoch
Stage/
Age
Age (Ma)
Jurassic Lower/
Early
Hettangian younger
Triassic Upper/
Late
Rhaetian 201.3 ~208.5
Norian ~208.5 ~227
Carnian ~227 ~237
Middle Ladinian ~237 ~242
Anisian ~242 247.2
Lower/
Early
Olenekian 247.2 251.2
Induan 251.2 251.902
Permian Lopingian Changhsingian older
Subdivision of the Triassic system
according to the ICS, as of 2020.[1]

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 ~227 to 208.5 million years ago.[2] It was preceded by the Carnian and succeeded by the Rhaetian.[3]

Stratigraphic definitionsEdit

 
Cast of a tridactyl footprint of a theropod dinosaur from the Norian of the Czech Republic.

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:

Norian lifeEdit

†AmmonoidsEdit

Ammonoidea of the Norian
Taxa Presence Location Description Images
Norian
Norian

ChondrichthyansEdit

Chondrichthyes of the Norian
Taxa Presence Location Description Images
Triassic United States, India An xenacanth elasmobranch

ActinopterygiansEdit

Actinopterygii of the Norian
Taxa Presence Location Description Images
Triassic Italy A non-neopterygian
Late Triassic Italy A pycnodont
Late Triassic Italy A semionotiform
Late Triassic to Middle Jurassic Austria, Italy A neopterygian
Late Triassic United States A teleosteomorph (modern ray-fin)
Middle Triassic to Late Triassic Austria, Italy
Late Triassic Austria, Italy A teleosteomorph (modern ray-fin)
Middle Triassic to Early Jurassic Italy A non-neopterygian
Late Triassic Italy A neopterygian
Triassic Italy, Austria A non-neopterygian
Middle Triassic to Late Triassic Italy The earliest gliding fish

CoelacanthsEdit

Actinistia of the Norian
Taxa Presence Location Description Images
Late Triassic to Cretaceous Italy A coelacanth

TemnospondylsEdit

Temnospondyls of the Norian
Taxa Presence Location Description Images
Arizona A genus of small metoposaurid trematosaurians, possibly juveniles of Koskinodon.
Chinle Formation, Colorado Chinlestegophis is an extinct genus of possible stereospondylian, considered to be related to metoposauroids, and has been noted to share many features with caecilians, a living group of legless burrowing amphibians. If Chinlestegophis is indeed both an advanced stereospondyl and a relative of caecilians, this means that stereospondyls, as a clade, survived to the present day.
South America; India A genus of chigutisaurid brachyopoid trematosaurians.
  • Cyclotosaurus
    • Cyclotosaurus hemprichi
    • Cyclotosaurus mordax
    • Cyclotosaurus naraserluki
    • Cyclotosaurus posthumus
A genus of large mastodonsaurid capitosaurians.
All over the US and India A genus of large metoposaurid trematosaurians.
India A genus of chigutisaurid brachyopoid trematosaurians.
Continental Europe A genus of large metoposaurid trematosaurians.

†ProcolophonomorphsEdit

Procolophonomorpha of the Norian
Taxa Presence Location Description Images
Late Triassic United States A genus of lizard-shaped parareptile

†IchthyosaursEdit

Ichthyosaurs of the Norian
Taxa Presence Location Description Images

Shonisaurus

  1. Shonisaurus popularis
Nevada, USA

†PlacodontsEdit

Placodonts of the Norian
Taxa Presence Location Description Images
Late Triassic Spain

†ThalattosaursEdit

Thalattosauria of the Norian
Taxa Presence Location Description Images
Late Triassic Italy An askeptosauroid
Late Triassic United States A thalattosauroid

†DrepanosaursEdit

Drepanosauromorpha of the Norian
Taxa Presence Location Description Images
Late Triassic United States A drepanosaur diapsid
Late Triassic New Mexico, United States A drepanosaur diapsid
Late Triassic Italy, United States A drepanosaur diapsid
Late Triassic United States A drepanosaur diapsid
Late Triassic Italy A drepanosaur diapsid
Late Triassic Italy A drepanosaur diapsid


ArchosauromorphsEdit

Archosauromorphs of the Norian
Taxa Presence Location Description Images
Alaunian/Sevatian Italy and Austria A tanystropheid.

Löwenstein Formation; Trossingen Formation, both in Germany; Huai Hin Lat, Thailand; Fleming Fjord Formation, Greenland

Proganochelys quenstedti is an extinct, primitive stem-turtle that has been hypothesized to be the sister taxon to all other turtles.
early Norian Paleorrota, Rio Grande do Sul, Brazil The latest surviving species of rhynchosaur, and the only one found in Norian deposits.

ArchosaursEdit

Archosaurs of the Norian
Taxa Presence Location Description Images
Pardonet Formation, British Columbia, Canada Sikannisuchus is a genus of large archosaur. It is known from the a posterior portion of skull roof and from other fragmentary remains.
latest Norian to early Rhaetian Lubliniec County, Poland The relation of Smok to other archosaurs has not yet been thoroughly studied; it may be a rauisuchid, prestosuchid or ornithosuchid crurotarsan, part of the crocodile line of archosaurs, or a theropod dinosaur more closely related to birds. At an estimated 5 to 6 metres (16 to 20 ft) in length, Smok was the largest carnivorous archosaur in central Europe at the time.
Stubensandstein, Löwenstein Formation, Germany A genus of rauisuchians originally thought to be a carnosaurian dinosaur.
Chinle Formation, New Mexico. A rauisuchid.
All across Europe Zanclodon is the name formally used for fossil material that might actually belongs to at least two genera of dinosaur from the Late Triassic among other genera.
DinosauromorphsEdit
Dinosauromorphs of the Norian
Taxa Presence Location Description Images
  • Dromomeron
    • Dromomeron romeri
    • Dromomeron gregorii
    • Dromomeron gigas
Carnian to Norian Timezgadiouine Formation, Argana Basin, Morocco
Chinle Formation, New Mexico
Eagle Basin, Colorado
Carnian to Norian Lossiemouth Sandstone Formation, Scotland
Cooper Canyon Formation, Texas
Bull Canyon Formation, Texas
DinosaursEdit
Dinosaurs of the Norian
Taxa Presence Location Description Images
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.
Early to middle Norian Placerias quarry, Bluewater Creek Formation, Arizona A close relative of the very similar Coelophysis, possibly belonging in the same genus. It is widely regarded as the oldest known neotheropod.
Carnian to Norian Chinle Formation, New Mexico, USA Coelophysis was a small, slenderly-built, ground-dwelling, bipedal carnivore, that could grow up to 3 m (9.8 ft) long. Coelophysis is known from a number of complete fossil skeletons of the species C. bauri.
Carnian to Norian Chinle Formation, New Mexico and Arizona and Bull Canyon Formation, New Mexico Genus of herrerasaurid dinosaur, measuring over 2 meters long.
Middle Norian Löwenstein Formation, Keuper, Germany Indeterminate coelophysoid theropod.
Disputed: Late Triassic or Early Jurassic, potentially as young as Sinemurian Lower Elliot Formation, 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.
210 Ma Cooper Canyon Formation, New Mexico, USA A large coelophysoid named after the giant monster movie character Godzilla.
Middle Norian Löwenstein Formation, Keuper, Germany Halticosaurus is a dubious genus of large theropod dinosaur.
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.
214-204 Ma, Carnian to Norian Trossingen Formation, Bavaria, Germany
Los Colorados Formation, Ischigualasto-Villa Unión Basin, Argentina Powellvenator was a coelophysoid theropod dinosaur.
Middle Norian Löwenstein Formation, Keuper, Germany A small coelophysoid theropod measuring about 1 meter long and 1kg heavy.
Dockum Group, Texas Protoavis is a problematic and controversial dinosaurian taxon known from fragmentary remains. The fossils were described as being from a primitive bird by its original describer. Considered a chimera by most paleontologists.
216 Ma Trossingen Formation, Thuringia, Germany A small coelophysoid theropod known from a single vertebra. Might be the same as Procompsognathus despite being based on a vertebra that is twice the size of the corresponding bone in Procompsognathus.
Norian Ghost Ranch, New Mexico, US One of the most basal theropods. Measured over 2 meters long.
Norian to Rhaetian
228-201.3 Ma, Norian to Rhaetian Los Colorados Formation, Argentina A medium-sized theropod. An adult skull, measured approximately 450 mm in length, suggesting a body length of approximately 4 m.
†PterosaursEdit
Pterosaurs of the Norian
Taxa Presence Location Description Images
CrurotarsansEdit
Crurotarsans of the Norian
Taxa Presence Location Description Images
Lower Elliot Formation, Lesotho
Los Colorados Formation, Argentina
Löwenstein Formation, Germany
AetosauriaEdit
Aetosaurs of the Norian
Taxa Presence Location Description Images
late Norian - Rhaetian
Carnian - Rhaetian
CrocodylomorphsEdit
Crocodylomorphs of the Norian
Taxa Presence Location Description Images
Late Carnian or early Norian

LepidosauromorphsEdit

Lepidosauromorpha of the Norian
Taxa Presence Location Description Images
Late Triassic United States A kuehneosaurid reptile
 
Kuehneosaurus (right) and Kuehneosuchus (left)
Late Triassic England, Luxemburg A kuehneosaurid reptile
Late Triassic England A kuehneosaurid reptile

MammaliamorphsEdit

Mammaliamorphs[4] of the Norian
Taxa Presence Location Description Images
Norian to Sinemurian Greenland and Western Europe A Late Triassic-Early Jurassic Kuehneotherian

ReferencesEdit

NotesEdit

  1. ^ "International Chronostratigraphic Chart" (PDF). International Commission on Stratigraphy. 2020.
  2. ^ According to Gradstein et al. (2004). Brack et al. (2005) give 226 to 207 million years
  3. ^ See for a detailed geologic timescale Gradstein et al. (2004)
  4. ^ The genera listed are included in Mammalia by Kielan-Jaworowska et al. (2004) but not by those who restrict the taxon to the crown group.

LiteratureEdit

  • 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 linksEdit