Anisian
In the geologic timescale, the Anisian is the lower stage or earliest age of the Middle Triassic series or epoch and lasted from 247.2 million years ago until 242 million years ago.[1] The Anisian age succeeds the Olenekian age (part of the Lower Triassic epoch) and precedes the Ladinian age.
Stratigraphic definitions
The stage and its name were established by Austrian geologists Wilhelm Heinrich Waagen and Carl Diener in 1895. The name comes from Anisus, the Latin name of the river Enns. The original type locality is at Großreifling in the Austrian state of Styria.
The base of the Anisian stage (also the base of the Middle Triassic series) is sometimes laid at the first appearance of conodont species Chiosella timorensis in the stratigraphic record. Other stratigraphers prefer to use the base of magnetic chronozone MT1n. The global reference profile for the base (the GSSP or golden spike) is at a flank of the mountain Deşli Caira in the Romanian Dobruja.[2]
The top of the Anisian (the base of the Ladinian) is at the first appearance of ammonite species Eoprotrachyceras curionii and the ammonite family Trachyceratidae. The conodont species Neogondolella praehungarica appears at the same level.
Especially in Central Europe the Anisian stage is sometimes subdivided into four substages: Aegean, Bythinian, Pelsonian and Illyrian.
The Anisian contains six ammonite biozones:
- zone of Nevadites
- zone of Hungarites
- zone of Paraceratites
- zone of Balatonites balatonicus
- zone of Kocaelia
- zone of Acrochordiceras
Anisian life
Chondrichthyans
| Chondrichthyes of the Anisian | ||||
|---|---|---|---|---|
| Taxa | Presence | Location | Description | Images |
| Mooreodontus | Triassic | Australia | An xenacanth elasmobranch[3] |  |
Actinopterygians
| Actinopterygii of the Anisian | ||||
|---|---|---|---|---|
| Taxa | Presence | Location | Description | Images |
| Triassic | China, Switzerland, Italy | A non-neopterygian |
   | |
| Lopingian to Middle Triassic | Switzerland, Italy | A non-neopterygian | ||
| Early Triassic to Early Jurassic | Netherlands, Germany | A neopterygian | ||
| Early Triassic to Middle Triassic | China | A non-neopterygian | ||
| Middle Triassic to Early Jurassic | Switzerland, Italy | A non-neopterygian | ||
| Triassic | China, United States, Switzerland, Italy | A non-neopterygian | ||
†Temnospondyls
| Temnospondyli of the Anisian | ||||
|---|---|---|---|---|
| Taxa | Presence | Location | Description | Images |
Batrachosuchus
|
Ntawere Formation, Zambia Burgersdorp Formation, South Africa Blina Shale, Australia |
A genus of brachyopid trematosaurian amphibians. |  | |
| Calmasuchus | Middle Triassic | Areniscas y Lutitas del Figaro Formation, Spain | A capitosaurian amphibian. | |
| Cherninia | Denwa Formation, India | A giant mastodonsaurid capitosaurian amphibian. |  | |
| Eocyclotosaurus | Grès à Voltzia Formation, France Röt Formation, Germany Otter Sandstone Formation, UK Moenkopi Formation, Arizona |
A capitosaurian amphibian. |  | |
| Eryosuchus | Yerrapalli Formation, India Donguz Formation, Russia |
A very large mastodonsaurid capitosaurian amphibian that could reach up to 3.5 m in length. |  | |
| Notobrachyops | Ashfield Shale, New South Wales, Australia. | A brachyopid trematosaurian amphibian. | ||
| Stenotosaurus | Middle Triassic | Germany, England | A capitosaurian amphibian. | |
| Vanastega | Cynognathus Assemblage Zone, Burgersdorp, South Africa. | A brachyopid trematosaurian amphibian. | ||
| Vigilius | Aegean/Bithynian | Arizona | A brachyopid trematosaurian amphibian. |  |
| Wellesaurus | Middle Triassic | USA, South Africa | A capitosaurian amphibian. | |
| Xenotosuchus | Middle Triassic | South Africa | A mastodonsaurid capitosaurian amphibian. | |
| Yuanansuchus | China | A heylerosaurid capitosaurian amphibian. | ||
†Ichthyopterygians
| †Ichthyopterygia of the Anisian | ||||
|---|---|---|---|---|
| Taxa | Presence | Location | Description | Images |
| Cymbospondylus | Middle Triassic | Switzerland, United States | An elongate ichthyosaur |  |
| Mixosaurus | Middle Triassic | Switzerland, Italy | An ichthyosaur |  |
| Omphalosaurus | Early to Middle Triassic | United States | An early ichthyosauriform with button-like teeth |  |
| Thalattoarchon | Middle Triassic | United States | One of the first marine macropredators after the Permian-Triassic extinction capable of eating prey that was similar in size to itself |  |
†Thalattosaurians
| Thalattosauria of the Anisian | ||||
|---|---|---|---|---|
| Taxa | Presence | Location | Description | Images |
| Askeptosaurus | Middle Triassic | Besano Formation, Italy | An askeptosauroid thalattosaur |  |
| Clarazia | Middle Triassic | Besano Formation, Switzerland | An thalattosauroid thalattosaur | |
| Hescheleria | Middle Triassic | Besano Formation, Switzerland | An thalattosauroid thalattosaur | |
| Thalattosaurus | Mid to Late Triassic | Canada | An thalattosauroid thalattosaur |  |
†Helveticosaurids
| Helveticosaurids of the Anisian | ||||
|---|---|---|---|---|
| Taxa | Presence | Location | Description | Images |
| Helveticosaurus | Anisian-Ladinian boundary | Switzerland |  | |
| Eusaurosphargis | Anisian-Ladinian boundary | Italy Netherlands |
||
†Saurosphargids
| Saurosphargids of the Anisian | ||||
|---|---|---|---|---|
| Taxa | Presence | Location | Description | Images |
| Largocephalosaurus | Guanling Formation, China | |||
| Saurosphargis | Poland Netherlands |
|||
| Sinosaurosphargis | Guanling Formation, China |  | ||
†Sauropterygians
| Sauropterygia of the Anisian | ||||
|---|---|---|---|---|
| Taxa | Presence | Location | Description | Images |
| Atopodentatus | Middle Triassic | China | A basal sauropterygian. It is the earliest known herbivorous marine reptile. |  |
| Diandongosaurus | Middle Triassic | China | A basal eosauropterygian | |
| Sanchiaosaurus | Middle Triassic | China | A basal nothosauroid | |
†Pistosaurs
| Pistosauria of the Anisian | ||||
|---|---|---|---|---|
| Taxa | Presence | Location | Description | Images |
| Augustasaurus | Middle Triassic | United States | A sauropterygian |  |
| Cymatosaurus | latest Olenekian to Anisian | Germany; Netherlands | A sauropterygian | |
| Pistosaurus | Anisian–Ladinian | France; Germany | A sauropterygian |  |
†Pachypleurosaurs
| Pachypleurosauria of the Anisian | ||||
|---|---|---|---|---|
| Taxa | Presence | Location | Description | Images |
| Anarosaurus | Middle Triassic | Netherlands | A sauropterygian | |
| Dactylosaurus | Middle Triassic | Central Europe | A sauropterygian | |
| Dianopachysaurus | Middle Triassic | China | A sauropterygian | |
| Keichousaurus | Middle Triassic | China | A sauropterygian |  |
| Odoiporosaurus | Middle Triassic | Italy | A sauropterygian | |
Serpianosaurus
|
upper Pelsonian | Germany | A sauropterygian | |
| Wumengosaurus | Middle Triassic | China | A sauropterygian |  |
†Nothosaurs
| Nothosauria of the Anisian | ||||
|---|---|---|---|---|
| Taxa | Presence | Location | Description | Images |
| Ceresiosaurus | Middle Triassic | Italy, Switzerland | Possibly a synonym of Lariosaurus |  |
| Germanosaurus | Middle Triassic | Germany | A sauropterygian | |
|
Middle Triassic | China Netherlands |
A sauropterygian | |
| Silvestrosaurus | Anisian-Ladinian boundary | Switzerland | Possibly a species of Lariosaurus | |
†Placodonts
| Placodonts of the Anisian | ||||
|---|---|---|---|---|
| Taxa | Presence | Location | Description | Images |
| Cyamodus | A derived cyamodontoid placodont |  | ||
| Palatodonta | early Anisian | Netherlands | A basal placodontiform sauropterygian | |
| Paraplacodus | Northern Italy | A basal placodont |  | |
| Pararcus | Middle Triassic | Netherlands | A basal placodont | |
| Placodus | Middle Triassic | Europe | A basal placodont |  |
Archosauromorphs
†Rhynchosaurs
| Rhynchosauria of the Anisian | ||||
|---|---|---|---|---|
| Taxa | Presence | Location | Description | Images |
| Moenkopi Formation, Arizona | A genus of hyperodapedontid rhynchosaur. | |||
| late Anisian | Otter Sandstone Formation, England | |||
| early Anisian | Burgersdorp Formation, South Africa | A basal rhynchosaur | ||
| late Anisian | Otter Sandstone Formation, England | A genus of hyperodapedontid rhynchosaur | ||
| early Anisian | Burgersdorp Formation, South Africa | One of the most basal rhynchosaurs | ||
| Bromsgrove Sandstone Formation, Warwickshire, England | A rather basal rhynchosaur, possibly a close relative of Rhynchosaurus | |||
| Yerrapalli Formation, India | A genus of hyperodapedontid rhynchosaur. | |||
| early Anisian | Burgersdorp Formation, South Africa | One of the most basal rhynchosaurs. It was small, measuring at around 30 cm (12 in) of length. | ||
| Tarporley Siltstone Formation, England | The first rhynchosaur to be described. It had a rather basal position in Rhynchosauria. | |||
| late Anisian | Tanganyika Territory, Tanzania. | A genus of hyperodapedontid rhynchosaur. | ||
†Tanystropheids
| Tanystropheids of the Anisian | ||||
|---|---|---|---|---|
| Taxa | Presence | Location | Description | Images |
| Amotosaurus | early Anisian | Röt Formation, Black Forest, southwestern Germany Vossenveld Formation, Netherlands |
||
| Dinocephalosaurus | Guanling Formation, China | A genus of long necked, aquatic archosauromorph. One particular specimen is notable for containing an embryo in its abdominal region strongly indicating viviparous reproduction. |  | |
| Macrocnemus | late Anisian to Ladinian | Besano Formation, Italy & Switzerland Falang Formation, China Prosanto Formation, Switzerland |
 | |
| Tanystropheus | Middle Triassic to Late Triassic | Falang Formation, China Muschelkalk Group, Germany Besano & Meride Formations, Switzerland Otter Sandstone Formation, UK Gevanim Formation, Israel |
 | |
Archosauriforms
| Archosauriforms of the Anisian | ||||
|---|---|---|---|---|
| Taxa | Presence | Location | Description | Images |
| Donguz Formation, Russia | An archosauriform closely related to archosaurs, similar in biology to euparkeriids. |
   | ||
| South Africa | Euparkeria is an extinct genus of archosauriform. It was a small reptile that was close to the ancestry of Archosauria. | |||
| Ermaying Formation, Shaanxi, China | A basal archosauriform, may be a chimera of fossils from the erythrosuchid Shansisuchus and an indeterminate archosaur. | |||
| Ermaying Formation, Shaanxi, China | A basal archosauriform, a member of Erythrosuchidae. | |||
| Ermaying Formation, Shaanxi, China | A euparkeriid closely related to Euparkeria. | |||
| Ermaying Formation, Shaanxi, China | An erythrosuchid. | |||
| Donguz Formation, Russia | A basal archosauriform, previously thought to be a close relative of Proterosuchus, a more basal taxon. | |||
| Donguz Formation, Russia | An erythrosuchid archosauriform. | |||
| Donguz Formation, Russia | A basal non-archosaurian archosauriform, possibly an erythrosuchid. | |||
| Ermaying Formation, Shaanxi, China | A dubious basal archosauriform. Might be an euparkeriid or even a suchian archosaur. | |||
Archosaurs
| Archosaurs of the Anisian | ||||
|---|---|---|---|---|
| Taxa | Presence | Location | Description | Images |
| Moenkopi Formation, Arizona | A ctenosauriscid poposauroid paracrocodylomorph. |
     | ||
| Manda Beds, Tanzania | A silesaurid dinosauriform. | |||
| Bromsgrove Sandstone Formation, England | A ctenosauriscid suchian. | |||
| Anisian to early Ladinian | Donguz Formation, Orenburg Oblast, Russia | A member of Aphanosauria, basal relatives of dinosaurs and pterosaurs. | ||
| Manda Formation, Tanzania | A ctenosauriscid suchian. | |||
| Ntawere Formation, Zambia | A silesaurid dinosauriform. | |||
| Manda Formation, Tanzania | A genus of loricatan suchian more basal than Prestosuchus. | |||
| Manda Beds, Tanzania | Possibly a dinosaur, the earliest known. | |||
| Guanling Formation, Pan County, China | A genus of aquatic poposauroid archosaur. | |||
| Manda Formation, Tanzania | A genus of loricatan suchian or possibly a species of Prestosuchus. | |||
| Manda Formation, Tanzania | An aphanosaurian archosaur. | |||
| Grenzbitumenzone, Switzerland and Italy | A genus of suchian archosaurs. Ticinosuchus shares many similarities with Paracrocodylomorpha. | |||
| Northwestern China | A genus of suchian archosaurs, possibly a gracilisuchid. The classification of Turfanosuchus has gone through much revision in the past due to its combination of features from both suchian archosaurs and earlier archosaur relatives such as Euparkeria. | |||
|
Röt Formation, Germany | A yet unnamed taxon of ctenosauriscid archosaur. | ||
| Yerrapalli Formation, India | An aphanosaurian archosaur. | |||
| 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. | |||
Therapsids
| Therapsids of the Anisian | ||||
|---|---|---|---|---|
| Taxa | Presence | Location | Description | Images |
| Africa, possibly also Eurasian distribution. |
 | |||
| Russia | ||||
| Tanzania | ||||
†Ceratitida
Ananorites Arthaberites Beyrichites Bosnites Buddhaites Bukowskiites Caucasites Danubites Gangadharites Japonites Laboceras Longobarditoides Mesocladiscites Noetlingites Parapinacoceras Parasageceras Phyllocladiscites Proavites Pseudodanubites Psilocladiscites Salterites Tropigymnites Xiphogymnites Pararcestes Sageceras
Lower
Alloptychites Anagymnites Grambergia Groenlandites Gymnites Lenotropites Pearylandites Silberlingites Isculites Stenopopanoceras
Middle
Acrochordiceras Alanites Anagymnotoceras Arctohungarites Balatonites Bulogites Cuccoceras Czekanowskites Epacrochordiceras Hollandites Huishuites Inaigymnites Ismidites Kiparisovia Malletophychites Nicomedites Phillipites Platycuccoceras Pronoetlingites Reiflingites Discoptychites Intornites Nevadisculites Paraceratites Parapopanoceras Proarcestes Longobardites Ptychites
Upper
Amphipopanoceras Aplococeras Arctogymnites Eudiscoceras Eutomoceras Gymnotoceras Halilucites Judicarites Kellnerites Metadinarites Nevadites Parakellnerites Proteusites Repossia Semiornites Serpianites Stoppaniceras Ticinites Tozerites Tropigastrites Joannites Epigymnites Ceratites Flexoptychites Frechites Norites Gevanites Hungarites
†Phylloceratida
Spinoleiophyllites Ussurites Monophyllites
Nautilida
Trachynautilus Thuringionautilus Styrionautilus
Lower
Middle
Upper
Holconautilus Proclydonautilus
†Aulacocerida
Crassiatractites Breviatractites
Lower
Pterioida
References
Notes
- ^ According to Gradstein et al. (2004); Brack et al. (2005) give 248 to 241 Ma
- ^ The GSSP was established by Grǎdinaru et al. (2007)
- ^ Ginter, M., Hampe, O., Duffin, C., 2010.Handbook of Paleoichthyology Volume 3D: Chondrichthyes: Paleozoic Elasmobranchii: Teeth. in Schultze, H. (ed.) Handbook of Paleoichthyology. Verlag Dr. Friedrich Pfeil, München
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.
- Grǎdinaru, E.; Orchard, M.J.; Nicora, A.; Gallet, Y.; Besse, J.; Krystyn, L.; Sobolev, E.S.; Atudorei, N.-V. & Ivanova, D.; 2007: The Global Boundary Stratotype Section and Point (GSSP) for the base of the Anisian Stage: Deşli Caira Hill, North Dobrogea, Romania, Albertiana 36, pp. 54–71.
- Gradstein, F.M.; Ogg, J.G. & Smith, A.G.; 2004: A Geologic Time Scale 2004, Cambridge University Press.
External links
- GeoWhen Database - Anisian
- Lower Triassic timescale at the website of the subcommission for stratigraphic information of the ICS
- Lower Triassic timescale at the website of Norges Network of offshore records of geology and stratigraphy.
