Aptian

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.[2]

The Aptian partly overlaps the upper part of the regionally used (in Western Europe) stage Urgonian.

The Selli Event, also known as OAE1a, was one of two oceanic Anoxic events in the Cretaceous period, which occurred around 120 Ma and lasted approximately 1 to 1.3 million years.[3][4] The Aptian extinction was a minor extinction event hypothesized to have occurred around 116 to 117 Ma.[5]

System/
Period
Series/
Epoch
Stage/
Age
Age (Ma)
Paleogene Paleocene Danian younger
Cretaceous Upper/
Late
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/
Early
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/
Late
Tithonian older
Subdivision of the Cretaceous system
according to the ICS, as of 2017.[1]

Stratigraphic definitions

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.

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

Examples of rock units formed during the Aptian are: Antlers Formation, Cedar Mountain Formation, Cloverly Formation, Elrhaz Formation, Jiufotang Formation, Little Atherfield, Mazong Shan, Potomac Formation, Santana Formation, Twin Mountains Formation, Xinminbao Group and Yixian Formation.

Palaeontology

Ammonitida

Tropaeum imperator
Tropaeum imperator

Belemnitida

Nautilida

Orthocerida

  • Upper
    • Zhuralevia

Phylloceratida

  • Upper
    • Euphylloceras

Sepiida

Ankylosaurs

GobisaurusNV
Gobisaurus
Minmi paravertebra dinosauria
Minmi
Sauropelta jconway
Sauropelta

Birds (avian theropods)

Ceratopsians

†Choristoderans

Crocodylomorpha

Fish

Mammalia

Ornithopods

Plesiosaurs

Kronosaurus bojacens1DB
Kronosaurus
Umoonasaurus BW
Umoonasaurus

Pterosaurs

Sauropods

Stegosaurs

Wuerhosaurus
Wuerhosaurus

Non-Avian Theropods

See also

References

Notes

  1. ^ Super User. "ICS - Chart/Time Scale". www.stratigraphy.org.
  2. ^ Gradstein et al. (2004)
  3. ^ Li, Yong-Xiang; Bralower, Timothy J.; Montañez, Isabel P.; Osleger, David A.; Arthur, Michael A.; Bice, David M.; Herbert, Timothy D.; Erba, Elisabetta; Premoli Silva, Isabella (2008-07-15). "Toward an orbital chronology for the early Aptian Oceanic Anoxic Event (OAE1a, ~ 120 Ma)". Earth and Planetary Science Letters. 271 (1–4): 88–100. Bibcode:2008E&PSL.271...88L. doi:10.1016/j.epsl.2008.03.055.
  4. ^ Leckie, R.; Bralower, T.; Cashman, R. (2002). "Oceanic anoxic events and plankton evolution: Biotic response to tectonic forcing during the mid-Cretaceous" (PDF). Paleoceanography. 17 (3): 1–29. Bibcode:2002PalOc..17.1041L. doi:10.1029/2001pa000623.
  5. ^ Archangelsky, Sergio. "The Ticó Flora (Patagonia) and the Aptian Extinction Event." Acta Paleobotanica 41(2), 2001, pp. 115-22.
  6. ^ Mortimer, Mickey. "List of Dromaeosaurids". Archived from the original on October 3, 2011. Retrieved July 8, 2011.

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. (in French)

External links

Albian

The Albian is both an age of the geologic timescale and a stage in the stratigraphic column. It is the youngest or uppermost subdivision of the Early/Lower Cretaceous epoch/series. Its approximate time range is 113.0 ± 1.0 Ma to 100.5 ± 0.9 Ma (million years ago). The Albian is preceded by the Aptian and followed by the Cenomanian.

Amargatitanis

Amargatitanis (meaning "Amarga giant") is a genus of dicraeosaurid sauropod dinosaur (a type of large, long-necked quadrupedal herbivorous dinosaur) from the Barremian-age (Lower Cretaceous) La Amarga Formation of Neuquén, Argentina.

Aptian extinction

The Aptian extinction was an extinction event of the early Cretaceous Period. It is dated to c. 116 or 117 million years ago, in the middle of the Aptian stage of the geological time scale, and has sometimes been termed the mid-Aptian extinction event as a result.

It is classified as a minor extinction event, rather than a major event like the famous Cretaceous–Paleogene extinction event that brought about the end of the "age of dinosaurs" and the Mesozoic Era. The Aptian event is most readily detected among marine rather than terrestrial fossil deposits. Nonetheless, "From a palaeobotanical perspective, the Aptian Extinction Event is an episode of importance, deserving a higher status among other minor events."The Aptian event may have been causally connected with the Rahjamal Traps volcanism episode in the Bengal region of India, associated with the Kerguelen hotspot of volcanic activity. (At the time in question, c. 116–117 Ma, India was located in the southern Indian Ocean; plate tectonics had not yet moved the Indian landmass into its present position.)

Note that the stegosaur group of dinosaurs went extinct around this time. Wuerhosaurus, probably the last of the stegosaurs, lived during this time.

Comahuesaurus

Comahuesaurus is a genus of sauropod dinosaur of the family Rebbachisauridae. It was found in the Lohan Cura Formation, in Argentina and lived during the Early Cretaceous, Aptian to Albian. The type species is C. windhauseni, named by Carballido and colleagues in 2012. It had originally been assigned to Limaysaurus by Salgado et al. (2004), but was later assigned its own genus based on the presence of diagnostic characters in the caudal centra, pubis and ischium.Comahuesaurus is known from abundant material compared to other rebbachisaurids; 37 caudal vertebrae, three fragmentary dorsal vertebrae and multiple appendicular elements, including a right humerus, pubis, ischium and a 113 cm long left femur. In their phylogenetic analysis, Carballido et al. (2012) placed Comahuesaurus in an intermediate position between basal rebbachisaurids such as Histriasaurus and the derived clade formed by subfamilies Rebbachisaurinae and Limaysaurinae.It shares with more derived rebbachisaurids a reduced hyposphene-hypantrum system, but hadn't yet completely lost said structure; that change would happen at some further point in the evolution of the clade, as it is so far only known to be fully absent in limaysaurines.

Early Cretaceous

The Early Cretaceous (geochronological name) or the Lower Cretaceous (chronostratigraphic name), is the earlier or lower of the two major divisions of the Cretaceous. It is usually considered to stretch from 146 Ma to 100 Ma.

Enantiornithes

Enantiornithes is a group of extinct avialans ("birds" in the broad sense), the most abundant and diverse group known from the Mesozoic era. Almost all retained teeth and clawed fingers on each wing, but otherwise looked much like modern birds externally. Over 80 species of enantiornitheans have been named, but some names represent only single bones, so it is likely that not all are valid. Enantiornitheans became extinct at the Cretaceous–Paleogene boundary, along with hesperornithids and all other non-avian dinosaurs. Enantiornitheans are thought to have left no living descendants.

Kronosaurus

Kronosaurus ( KRON-o-SAWR-əs; meaning "lizard of Kronos") is an extinct genus of short-necked pliosaur. With an estimated length of 9 to 10.9 metres (30 to 36 ft), it was among the largest pliosaurs, and is named after the leader of the Greek Titans, Cronus. It lived in the Early Cretaceous period (Aptian to Late Albian). Fossil material has been recovered from the Toolebuc Formation (middle to late Albian) and Wallumbilla Formations (Aptian) of Queensland and New South Wales in Australia, and from the upper Paja Formation (late Aptian) in Boyacá, Colombia, and assigned to two species.

Lavocatisaurus

Lavocatisaurus is a genus of sauropod in the family Rebbachisauridae from the Early Cretaceous (Aptian to Albian) Rayoso Formation of the Neuquén Basin, northern Patagonia, Argentina.

Ligabuesaurus

Ligabuesaurus is a genus of dinosaur from the Early Cretaceous (Late Aptian to Early Albian stage, around 110 million years ago). It was a basal titanosaurid sauropod which lived in what is now Argentina. The type species, Ligabuesaurus leanzai, was described by Jose Bonaparte, Gonzalez Riga, and Sebastián Apesteguía in 2006, based on a partial skeleton. The specific name, leanzai, is dedicated to the geologist Dr. Héctor A. Leanza, who discovered the skeleton in the Lohan Cura Formation.

Longipterygidae

Longipterygidae is a family of early enantiornithean birds from the early Cretaceous Period of China. All known specimens come from the Jiufotang Formation and Yixian Formation, dating to the early Aptian age, 125-120 million years ago.

Lurdusaurus

Lurdusaurus ('heavy lizard') is a genus of large ornithopod dinosaur that lived in the Aptian stage of the Early Cretaceous, sometime between 121 and 112 million years ago.

Mnyamawamtuka

Mnyamawamtuka (pronounced Mm-nya-ma-wah-mm-too-ka; meaning "beast of the Mtuka river drainage" in Kiswahili) is a genus of lithostrotian titanosaur dinosaur from the Late Cretaceous Galula Formation in Tanzania. The type and only species is M. moyowamkia.

Neobatrachia

The Neobatrachia are a suborder of the Anura, the order of frogs and toads.

This suborder is the most advanced and apomorphic of the three anuran orders alive today, hence its name, which literally means "new frogs" (from the hellenic words neo, meaning "new" and batrachia, meaning "frogs"). It is also by far the largest of the three; its more than 5,000 different species make up over 96% of all living anurans.

The differentiation between Archaeobatrachia, Mesobatrachia, and Neobatrachia is based primarily on anatomic differences, especially the skeletal structure, as well as several visible characteristics and behaviors.

Nodosauridae

Nodosauridae is a family of ankylosaurian dinosaurs, from the Late Jurassic to the Late Cretaceous period of what are now North America, Europe, Asia, Africa, and Antarctica.

Omnivoropterygidae

Omnivoropterygidae (meaning "omnivorous wings") is a family of primitive avialans known exclusively from the Jiufotang Formation of China. They had short skeletal tails and unusual skulls with teeth in the upper, but not lower, jaws. Their unique dentition has led some scientists to suggest an omnivorous diet for them. The family was named by Stephen A. Czerkas & Qiang Ji in 2002, though its junior synonym Sapeornithidae is often used instead, though it was named four years later in 2006. It is the only named family in the order Omnivoropterygiformes.

Polycotylidae

Polycotylidae is a family of plesiosaurs from the Cretaceous, a sister group to Leptocleididae.

With their short necks and large elongated heads, they resemble the pliosaurs, but closer phylogenetic studies indicate that they share many common features with the Plesiosauridae and Elasmosauridae. They have been found worldwide, with specimens reported from New Zealand, Australia, Japan, Morocco, the US, Canada, Eastern Europe, and South America.

Protostegidae

Protostegidae is a family of extinct marine turtles that lived during the Cretaceous period. The family includes some of the largest sea turtles that ever existed. The largest, Archelon, had a head one metre (39 in) long. Like most sea turtles, they had flattened bodies and flippers for front appendages; protostegids had minimal shells like leatherback turtles of modern times.

Ranunculales

Ranunculales is an order of flowering plants. Of necessity it contains the family Ranunculaceae, the buttercup family, because the name of the order is based on the name of a genus in that family. Ranunculales belongs to a paraphyletic group known as the basal eudicots. It is the most basal clade in this group; in other words, it is sister to the remaining eudicots. Widely known members include poppies, barberries, and buttercups.

Tapuiasaurus

Tapuiasaurus (meaning "Tapuia lizard") is a genus of titanosaur which lived during the Lower Cretaceous period (Aptian age) in what is now Minas Gerais, Brazil. Its fossils, including a partial skeleton with a nearly complete skull, have been recovered from the Quiricó Formation of the São Francisco Basin in Minas Gerais, eastern Brazil. This genus was named by Hussam Zaher, Diego Pol, Alberto B. Carvalho, Paulo M. Nascimento, Claudio Riccomini, Peter Larson, Rubén Juárez Valieri, Ricardo Pires Domingues, Nelson Jorge da Silva Jr. and Diógenes de Almeida Campos in 2011, and the type species is Tapuiasaurus macedoi.

Cenozoic era
(present–66.0 Mya)
Mesozoic era
(66.0–251.902 Mya)
Paleozoic era
(251.902–541.0 Mya)
Proterozoic eon
(541.0 Mya–2.5 Gya)
Archean eon (2.5–4 Gya)
Hadean eon (4–4.6 Gya)

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