The Aptian is an age in the geologic timescale or a stage in the stratigraphic column. It is a subdivision of the Early or Lower Cretaceous epoch or series and encompasses the time from 125.0 ± 1.0 Ma to 113.0 ± 1.0 Ma (million years ago), approximately. The Aptian succeeds the Barremian and precedes the Albian, all part of the Lower/Early Cretaceous.
The Aptian partly overlaps the upper part of the regionally used (in Western Europe) stage Urgonian.
The Aptian was named after the small city of Apt in the Provence region of France, which is also known for its crystallized fruits. The original type locality is in the vicinity of Apt. The Aptian was introduced in scientific literature by French palaeontologist Alcide d'Orbigny in 1840.
The base of the Aptian stage is laid at magnetic anomaly M0r. A global reference profile for the base (a GSSP) had in 2009 not yet been appointed. The top of the Aptian (the base of the Albian) is at the first appearance of coccolithophore species Praediscosphaera columnata in the stratigraphic record.
In the Tethys domain, the Aptian contains eight ammonite biozones:
zone of Hypacanthoplites jacobi
zone of Nolaniceras nolani
zone of Parahoplites melchioris
zone of Epicheloniceras subnodosocostatum
zone of Duffrenoyia furcata
zone of Deshayesites deshayesi
zone of Deshayesites weissi
zone of Deshayesites oglanlensis
Sometimes the Aptian is subdivided in three substages or subages: Bedoulian (early or lower), Gargasian (middle) and Clansayesian (late or upper).
Antlers Formation, Cedar Mountain Formation, Cloverly Formation, Elrhaz Formation, Jiufotang Formation, Little Atherfield, Mazong Shan, Potomac Formation, Santana Formation, Twin Mountains Formation, Xinminbao Group, Yixian Formation
Pictetia
Eogaudryceras
Georgioceras
Lithancylus
Salfeldiella
Zuercherella
Lower
Eotetragonites
Pseudosaynella
Roloboceras
Helicancylus
Procheloniceras
Prodeshayesites
Shastoceras
Ammonitoceras
Australiceras
Cheloniceras
Cicatrites
Colombiceras
Dufrenoya
Melchiorites
Parahoplites
Upper
Hypacanthoplites
Sinzovia
Trochleiceras
Mathoceratites
Metahamites
Neosilesites
Protanisoceras
Ammonoceratites
Beudanticeras
Gyaloceras
Hulenites
Knemiceras
Uhligella
Acanthohoplites
Acanthoplites
Argonauticeras
Burckhardites
Cloioceras
Diadochoceras
Diodochoceras
Eodouvilleiceras
Epancyloceras
Epicheloniceras
Gargasiceras
Jauberticeras
Kazanskyella
Mathoceras
Megatyloceras
Miyakoceras
Nodosohoplites
Nolaniceras
Protacanthoplites
Somalites
Theganoceras
Tropaeum
Gabbioceras
Tetragonites
Desmoceras
Hamites
Vectibelus
Conoteuthis
Lower
Tetrabelus
Peratobelus
Parahibolites
Heminautilus
Carinonautilus
Upper
Zhuralevia
Upper
Euphylloceras
Upper
Adygeya
Naefia
Boluochia zhengi
Chaoyangia beishanensis
Confuciusornis sanctus
Cuspirostrisornis houi
Jeholornis prima
Jixiangornis orientalis
Largirostrornis sexdentoris
Longchengornis sanyanensis
Longipteryx chaoyangensis
Sapeornis chaoyangensis
Sinornis santensis/Cathayornis yandica
Songlingornis linghensis
Yanornis martini
Yixianornis grabaui
Sarcosuchus
Hybodus
Jinanichthys longicephalus
Lycoptera davidi
Lycoptera muroii
Peipiaosteus pani
Protosephurus liui
Sinamia zdanskyi
Anhanguera
Araripedactylus dehmi
Araripesaurus castilhoi
Arthurdactylus conandoylei
Boreopterus cuiae
Brasileodactylus araripensis
Cearadactylus atrox
Chaoyangopterus zhangi
Dsungaripterus weii
Dsungaripterus brancai
Eoazhdarcho liaoxiensis
Eopteranodon lii
Gegepterus changi
Haopterus gracilis
Hongshanopterus lacustris
Huaxiapterus benxiensis
Huaxiapterus corollatus
Huaxiapterus jii
Istiodactylus latidens
Istiodactylus sinensis
Jidapterus edentus
Liaoningopterus gui
Liaoxipterus brachyognathus
Lonchodectes
Longchengpterus zhaoi
Ludodactylus sibbicki
Nemicolopterus crypticus
Nurhachius ignaciobritoi
Ornithocheirus simus
Ornithocheirus mesembrinus
Pricesaurus megalodon
Santanadactylus
Sinopterus dongi
Sinopterus gui
Tapejara navigans
Tapejara wellnhoferi
Thalassodromeus sethi
Tropeognathus mesembrinus
Tropeognathus robustus
Tupandactylus imperator
