Aptian

System	Series	Stage	Age (Ma)
Paleogene	Paleocene	Danian	younger
Cretaceous	Upper	Maastrichtian	66.0–72.1
		Campanian	72.1–83.6
		Santonian	83.6–86.3
		Coniacian	86.3–89.8
		Turonian	89.8–93.9
		Cenomanian	93.9–100.5
	Lower	Albian	100.5–~113.0
		Aptian	~113.0–~125.0
		Barremian	~125.0–~129.4
		Hauterivian	~129.4–~132.9
		Valanginian	~132.9–~139.8
		Berriasian	~139.8–~145.0
Jurassic	Upper	Tithonian	older
Subdivision of the Cretaceous system according to the IUGS, as of July 2012.

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 112.0 ± 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.

Stratigraphic definitions

The Aptian was named after the small city of Apt in the Provence region of France. 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.

Subdivision

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).

Lithostratigraphic units

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

Palaeontology

†Ammonitida

• Pictetia
• Eogaudryceras
• Georgioceras
• Lithancylus
• Salfeldiella
• Zuercherella

• Lower
  • Eotetragonites
  • Pseudosaynella
  • Roloboceras
  • Helicancylus
  • Procheloniceras
  • Prodeshayesites
  • Shastoceras
  • Ammonitoceras
  • Australiceras
  • Cheloniceras
  • Cicatrites
  • Colombiceras
  • Dufrenoya
  • Melchiorites
  • Parahoplites

Tropaeum imperator

• 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

†Belemnitida

• Vectibelus
• Conoteuthis

• Lower
  • Tetrabelus
  • Peratobelus
  • Parahibolites

Nautilida

• Heminautilus
• Carinonautilus

†Orthocerida

• Upper
  • Zhuralevia

†Phylloceratida

• Upper
  • Euphylloceras

Sepiida

• Upper
  • Adygeya
  • Naefia

†Ankylosaurs

†Ankylosauria of the Aptian
Taxa	Presence	Location	Description	Images
†Cedarpelta †Cedarpelta bilbeyhallorum		Cedar Mountain Formation, Utah, USA		Minmi Sauropelta
†Gobisaurus †Gobisaurus domoculus		Ulansuhai Formation, Inner Mongolia, China
†Liaoningosaurus †Liaoningosaurus paradoxus		Yixian Formation, Liaoning, China	Nodosaurid with ventral armor plating
†Minmi †Minmi paravertebra		Bungil Formation, Queensland, Australia	Small (1 meter long) primitive ankylosaur
†Sauropelta †Sauropelta edwardsorum	Aptian to Albian	Cloverly Formation, Wyoming, Montana, Utah, USA	A medium-sized nodosaurid, measuring about 5 meters (16.5 ft) long, Sauropelta had a distinctively long tail which made up about half of its body length. Its neck and back were protected by an extensive bony body armor including characteristically large spines
†Shamosaurus †Shamosaurus scutatus		Mongolia	Ankylosaurid

Birds

• 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

†Ceratopsians

†Ceratopsia of the Aptian
Taxa	Presence	Location	Description	Images
†Archaeoceratops †Archaeoceratops oshimai		Mazong Shan, Gansu, China	A basal neoceratopsian, appears to have been bipedal and quite small (about 1 meter long) with a comparatively large head. Unlike many later ceratopsians it doesn't have any horns and has only a small bony frill projecting from the back of its head.	Archaeoceratops Auroraceratops Psittacosaurus meileyingensis Psittacosaurus mongoliensis
†Auroraceratops †Auroraceratops rugosus		Xinminbao Group, Gansu, China	Basal neoceratopsian
†Psittacosaurus †Psittacosaurus meileyingensis †Psittacosaurus mongoliensis		China, Mongolia, Russia	Psittacosaurid Ceratopsian
†Serendipaceratops †Serendipaceratops arthurcclarkei		Victoria, Australia	2 meters long early ceratopsian

†Choristoderans

†Choristoderans of the Aptian
Taxa	Presence	Description	Images
Genus: †Hyphalosaurus †Hyphalosaurus lingyuanensis †Hyphalosaurus baitaigouensis		Yixian Formation, Liaoning Province, China	Hyphalosaurus
Genus: †Monjurosuchus †Monjurosuchus splendens		China and Japan

Crocodylomorpha

• Sarcosuchus

Fish

• Hybodus
• Jinanichthys longicephalus
• Lycoptera davidi
• Lycoptera muroii
• Peipiaosteus pani
• Protosephurus liui
• Sinamia zdanskyi

Mammalia

Mammals of the Hauterivian
Taxa	Presence	Location	Description	Images
Eobaatar	several species from Hauterivian to Albian	Spain, Mongolia		Jeholodens Repenomamus Yanoconodon
Jeholodens		Yixian Formation, Liaoning, China	A long-tailed, nocturnal tetrapod (with prensile fingers and toes) which hunted insects, its food, during the night
Repenomamus		Yixian Formation, Liaoning, China	The largest mammal known from the Cretaceous period of the Mesozoic, and the one for which there is the best evidence that it fed on dinosaurs.
Teinolophos		Flat Rocks, Victoria, Australia	The earliest known monotreme.
Yanoconodon		Yixian Formation, Hebei, China	A small mammal, barely 13 centimetres (5 inches) long. It was lightly built and fed on insects, worms and other invertebrates, probably hunting at night. Like most early mammals, Yanoconodon had short, sprawling legs and claws that were most likely used for burrowing underground or digging

†Ornithopods

†Ornithopoda of the Aptian
Taxa	Presence	Location	Description	Images
†Atlascopcosaurus †Atlascopcosaurus loadsi	Aptian/Albian	Dinosaur Cove, Victoria, Australia	2–3 meters long hypsilophodont	Atlascopcosaurus Dollodon Iguanodon Lurdusaurus Mantellisaurus Ouranosaurus Qantassaurus Tenontosaurus tilletti Theiophytalia
†Changchunsaurus †Changchunsaurus parvus		Quantou Formation, Jilin, China	As a small basal ornithopod, Changchunsaurus would have been a swift bipedal herbivore, feeding close to the ground.
†Dollodon †Dollodon bampingi	Barremian-?Aptian	Bernissart, Belgium; ?England; ?Germany	A lightly constructed iguanodont, about 6 meters long (20 ft), estimated to weigh about 1 ton
†Equijubus †Equijubus normani		Mazong Shan, Gansu, China	Primitive hadrosaur or iguanodont
†Iguanodon †Iguanodon bernissartensis		Asia, Europe, North America	Worldwide distributed, type genus of the Iguanodontia. 10 meters long
†Lurdusaurus †Lurdusaurus arenatus		Niger	9 meters long heavily built Iguanodont
†Mantellisaurus †Mantellisaurus atherfieldensis		Atherfield, England, UK	formerly known as Iguanodon atherfieldensis
†Osmakasaurus †Osmakasaurus depressus		Lakota Formation, South Dakota, USA	A genus intermediate between Camptosaurus and more derived iguanodonts.
†Ouranosaurus †Ouranosaurus nigeriensis		Echkar Formation, Niger	7 meters long hadrosauroid, possibly with a sail on the back
†Planicoxa †Planicoxa venenica		Cedar Mountain Formation, Utah	A genus of advanced iguanodont
†Qantassaurus †Qantassaurus intrepidus		Victoria, Australia	1.8 meter long hypsilophodontid
†Siluosaurus †Siluosaurus zhanggiani		Xinminbao Group, Gansu, China	A hypsilophodontid or other basal ornithopod, Siluosaurus would have been a bipedal herbivore.
†Tenontosaurus †Tenontosaurus tilletti †Tenontosaurus dossi		Cloverly Formation, Wyoming and Montana, Antlers Formation, Oklahoma, Twin Mountains Formation, Texas, USA	8 meters long early iguanodont
†Theiophytalia †Theiophytalia kerri	Aptian to Albian	Purgatoire Formation, Colorado, USA	An iguanodont described as intermediate in derivation between Camptosaurus and Iguanodon
†Zephyrosaurus †Zephyrosaurus schaffi		Cloverly Formation, Montana, USA	Hypsilophodont

†Plesiosaurs

†Plesiosaurs of the Aptian
Taxa	Presence	Location	Description	Images
†Brachauchenius †Brachauchenius lucasi		Kansas, USA; Colombia	A pliosaur that grew to around 10 meters in length, it represents the last known occurrence of a pliosaur in North America.	Brachauchenius Kronosaurus Umoonasaurus
†Callawayasaurus †Callawayasaurus colombiensis		Paja Formation, Colombia	8 meters long elasmosaurid
†Kronosaurus †Kronosaurus boyacensis	Aptian to Albian	Boyaca, Colombia	Among the largest pliosaurs, body-length estimates put the total length of Kronosaurus at 9–10 meters
†Umoonasaurus †Umoonasaurus demoscyllus		Australia	Relatively small cryptocleidid, around 2.5 m long, identified by the three crest-ridges on its skull.

†Pterosaurs

• 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

†Sauropods

†Sauropods of the Aptian
Taxa	Presence	Location	Description	Images
†Amazonsaurus †Amazonsaurus maranhensis		Itapecuru Formation, Maranhão, Brazil	A genus of 12 meters long diplodocoid.	Astrodon Jobaria Malawisaurus Nigersaurus Sauroposeidon
†Astrodon †Astrodon johnstoni		Arundel Formation, Maryland, USA	A large titanosaur, adults are estimated to have been more than 9m high and 15m to 18m long.
†Fusuisaurus †Fusuisaurus zhaoi		Napai Formation, Guangxi, China	Probably a basal titanosaur, known by fragmentary postcranial remains
†Jobaria †Jobaria tiguidensis	Aptian or Albian	Sahara Desert	Seems to be a very primitive sauropod. Unlike other Cretaceous sauropods, Jobaria had spoon-shaped teeth.
†Karongasaurus †Karongasaurus gittelmani		Malawi	Titanosaurid which fossils consist solely of parts of a lower mandible and a few teeth
†Ligabuesaurus †Ligabuesaurus leanza		Argentina	A basal titanosaurid
†Malawisaurus †Malawisaurus dixeyi		Malawi	One of the few titanosaurs for which skull material has been found
†Nigersaurus †Nigersaurus taqueti		Elrhaz Formation, Niger	Diplodocoid dinosaur, one of the most common genera found in the rich fossil vertebrate fauna of the Elrhaz Formation
†Paluxysaurus †Paluxysaurus jonesi		Twin Mountains Formation, Texas, USA	A basal titanosauriform
†Sauroposeidon †Sauroposeidon proteles		Antlers Formation, Oklahoma, USA	The last known giant brachiosaurid; extrapolations indicate that the head of Sauroposeidon could reach 17 m in height, making it the tallest known dinosaur. With an estimated length of 30 m and a mass of 36–40 MT it also ranks among the longest and heaviest.
†Tangvayosaurus †Tangvayosaurus hoffeti		Grès Supérior Formation, Laos	A basal titanosaur, known from the remains of two or three individuals.
†Venenosaurus †Venenosaurus dicrocei		Cedar Mountain Formation, Utah, USA	A titanosaur, known from an incomplete skeleton of an adult and a juvenile

†Stegosaurs

†Stegosauria of the Aptian
Taxa	Presence	Location	Description	Images
†Wuerhosaurus †Wuerhosaurus homheni †Wuerhosaurus ordosensis		Xinjiang, Inner Mongolia, China	7 meter long stegosaurid	Wuerhosaurus

†Non Avian Theropods

†Non Avian Theropods of the Aptian
Taxa	Presence	Location	Description	Images
†Acrocanthosaurus †Acrocanthosaurus atokensis		Texas, Oklahoma, ?Maryland, USA	Likely an apex predator, up to 12 meters long. Classification disputed (Carcharodontosaurid or Allosaurid)	Acrocanthosaurus Deinonychus Genyodectes Huaxiagnathus Kryptops Neovenator Protarchaeopteryx Sinornithoides Sinosauropteryx Suchomimus Tyrannotitan Utahraptor
†Cryptovolans †Cryptovolans pauli		Jiufotang Formation, Liaoning, China	Small (90 centimeters long feathered dromeaosaurid, possibly the same species as Microraptor
†Deinonychus †Deinonychus antirrhopus		Cloverly Formation, Montana and Wyoming, Antlers Formation, Oklahoma, Potomac Formation, Maryland, USA	3–4 meters long carnivorous dromaeosaurid
†?Genyodectes †Genyodectes serus		Chubut Province, Argentina	Possibly ceratosaurian
†Huaxiagnathus †Huaxiagnathus orientalis		Yixian Formation, Liaoning, China	Large (1.8 meter long) compsognathid
†Kryptops †Kryptops palaios		Elrhaz Formation, Niger	Earliest-known abelisaurid
†Neovenator †Neovenator salerii		Isle of Wight, England, UK	7.5 meters long allosaurid
†Protarchaeopteryx †Protarchaeopteryx robusta		Yixian Formation, Liaoning, China	Primitive oviraptosaur, possibly synonymous with Incisivosaurus
†Similicaudipteryx †Similicaudipteryx yixianensis		Jiufotang Formation, Liaoning, China	Caudipterid oviraptosaur
†Sinornithoides †Sinornithoides youngi		China	1 meter long troodontid
†Sinosauropteryx †Sinosauropteryx prima		Liaoning, China	1.20 meter long compsognathid, fossilized with traces of color pigmentation in its feathers
†Suchomimus †Suchomimus tenerensis		Tenere, Niger	12 meters long spinosaurid
†Tyrannotitan †Tyrannotitan chubutensis		Chubut Province, Argentina	12 meters long carcharodontosaurid
Utahraptor		North America	The largest known dromaeosaurid

References

Literature

• Gradstein, F.M.; Ogg, J.G. & Smith, A.G.; 2004: A Geologic Time Scale 2004, Cambridge University Press.
• d'Orbigny, A.C.V.M.; 1842: Paléontologie française: Terrains crétacés, vol. ii.(French)

External links

• GeoWhen Database - Aptian
• Mid-Cretaceous timescale, at the website of the subcommission for stratigraphic information of the ICS
• Stratigraphic charts of the Lower Cretaceous: [1] and [2], at the website of Norges Network of offshore records of geology and stratigraphy