Coniacian

The Coniacian is an age or stage in the geologic timescale. It is a subdivision of the Late Cretaceous epoch or Upper Cretaceous series and spans the time between 89.8 ± 1 Ma and 86.3 ± 0.7 Ma (million years ago). The Coniacian is preceded by the Turonian and followed by the Santonian.[2]

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 Coniacian is named after the city of Cognac in the French region of Saintonge. It was first defined by French geologist Henri Coquand in 1857.

The base of the Coniacian stage is at the first appearance of the inoceramid bivalve species Cremnoceramus rotundatus. An official reference profile for the base (a GSSP) had in 2009 not yet been appointed.

The top of the Coniacian (the base of the Santonian stage) is defined by the appearance of the inoceramid bivalve Cladoceramus undulatoplicatus.

The Coniacian overlaps the regional Emscherian stage of Germany, which is roughly coeval with the Coniacian and Santonian stages. In magnetostratigraphy, the Coniacian is part of magnetic chronozone C34, the so-called Cretaceous Magnetic Quiet Zone, a relatively long period with normal polarity.

Sequence stratigraphy and geochemistry

After a maximum of the global sea level during the early Turonian, the Coniacian was characterized by a gradual fall of the sea level. This cycle is in sequence stratigraphy seen as a first order cycle. During the middle Coniacian a shorter, second order cycle, caused a temporary rise of the sea level (and global transgressions) on top of the longer first order trend. The following regression (Co1, at 87,0 Ma) separates the Middle from the Upper Coniacian substage. An even shorter third order cycle caused a new transgression during the Late Coniacian.

Beginning in the Middle Coniacian, an anoxic event (OAE-3) occurred in the Atlantic Ocean, causing large scale deposition of black shales in the Atlantic domain. The anoxic event lasted till the Middle Santonian (from 87.3 to 84.6 Ma) and is the longest and last such event during the Cretaceous period.[3]

Subdivision

The Coniacian is often subdivided into Lower, Middle and Upper substages. It encompasses three ammonite biozones in the Tethys domain:

In the boreal domain the Coniacian overlaps just one ammonite biozone: that of Forresteria petrocoriensis

Palaeontology

†Ornithischians

†Sauropods

†Plesiosaurs

Plesiosaurs of the Coniacian
Taxa Presence Location Description Images

Dravidosaurus

Coniacian Trichinopoly Group, India A small plesiosaur of undeterminate length.

Theropods

References

Notes

  1. ^ Super User. "ICS - Chart/Time Scale". www.stratigraphy.org.
  2. ^ See Gradstein et al. (2004) for a detailed version of the ICS' geologic timescale
  3. ^ See Meyers et al. (2006)

Literature

  • Gradstein, F.M.; Ogg, J.G. & Smith, A.G.; 2004: A Geologic Time Scale 2004, Cambridge University Press.
  • Meyers, P.A.; Bernasconi, S.M. & Forster, A.; 2006: Origins and accumulation of organic matter in expanded Albian to Santonian black shale sequences on the Demerara Rise, South American margin, Organic Geochemistry 37, pp 1816–1830.

External links

Baalsaurus

Baalsaurus (named after the dinosaur fossil site Baal in Argentina, which in turn is named after the ancient Phoenician god Baal) is a genus of titanosaurian sauropod dinosaur from the Late Cretaceous of Neuquén Province, Patagonia, Argentina. The type and only known species is B. mansillai, with the specific name honoring the discoverer Juan Eduardo Mansilla, a museum technician at the Geology and Paleontology Museum of the National University of Comahue.

The holotype specimen, MUCPv-1460, is a mostly complete right dentary that was found in rocks of the upper Portezuelo Formation. The dentary is squared-off instead of curved when viewed from above or below, with the teeth crowded into the front of the jaw, making it similar to the jaw of Antarctosaurus, Brasilotitan, and to a lesser extent Bonitasaura. The specimen is currently held at the Geology and Paleontology Museum of the National University of Comahue, Parque Natural Geo-Paleontológico Proyecto Dino, Barreales Lake.

Cynodontosuchus

Cynodontosuchus is an extinct genus of baurusuchid mesoeucrocodylian. Fossils have been found from Argentina of Late Cretaceous age from the Bajo de la Carpa Formation (dating back to the Santonian) as well as the Pichi Picun Leufu Formation (dating back to the Coniacian and Santonian). Fossils also have been found in the Tiupampan Santa Lucía Formation of Bolivia.

Futalognkosaurus

Futalognkosaurus ( FOO-tə-long-ko-SAW-rəs; meaning "giant chief lizard") is a genus of titanosaurian dinosaur. The herbivorous Futalognkosaurus lived approximately 87 million years ago in the Portezuelo Formation, in what is now Argentina, of the Coniacian stage of the late Cretaceous Period. The fish and fossilized leaf debris on the site, together with other dinosaur remains, suggest a warm tropical climate in Patagonia during this period.

Goniopholididae

Goniopholididae is an extinct family of moderate-sized semi-aquatic crocodyliforms superficially similar to living crocodiles (but see below). They lived between the Early Jurassic and the Late Cretaceous.

Iguanidae

The Iguanidae are a family of lizards composed of iguanas and related species.

Kaijutitan

Kaijutitan (meaning "Kaiju titan" after the type of Japanese movie monsters) is a genus of basal titanosaur dinosaur from the Sierra Barrosa Formation from Neuquén Province in Argentina. The type and only species is Kaijutitan maui.

Macrogryphosaurus

Macrogryphosaurus (meaning "big enigmatic lizard") is a genus of basal iguanodont dinosaur from the Coniacian age Upper Cretaceous Sierra Barrosa Formation (Neuquén Group) of Patagonia, Argentina. It was described by Jorge Calvo and colleagues, with M. gondwanicus as type species (referring to the animal coming from Gondwana).

Malarguesaurus

Malarguesaurus is a genus of titanosauriform sauropod dinosaur from the Late Cretaceous of Mendoza Province, Argentina. Its fossils, consisting of tail vertebrae, chevrons, ribs, and limb bones, were found in the late Turonian-early Coniacian-age (~89 million years old) Portezuelo Formation of the Neuquén Group. The type species, described by González Riga et al. in 2008, is M. florenciae.

Megaraptor

Megaraptor ("giant thief") is a genus of large theropod dinosaur that lived in the Turonian to Coniacian ages of the Late Cretaceous. Its fossils have been discovered in the Patagonian Portezuelo Formation of Argentina. Initially thought to have been a giant dromaeosaur-like coelurosaur, it was classified as a neovenatorid allosauroid in previous phylogenies, but more recent phylogeny and discoveries of related megaraptoran genera has placed it as either a basal tyrannosauroid or a basal coelurosaur.

Mendozasaurus

Mendozasaurus is a genus of sauropod dinosaur. It was a member of Titanosauria, which were massive sauropods that were common on the southern landmasses during the Cretaceous period. The titanosaurian sauropod dinosaur Mendozasaurus neguyelap is represented by several partial skeletons from a single locality within the Coniacian (lower Upper Cretaceous) Sierra Barrosa Formation in the south of Mendoza Province, northern Neuquén Basin, Argentina.

The type species, Mendozasaurus neguyelap, was described by Argentine paleontologist Bernardo Javier González Riga in 2003. Mendozasaurus is the first dinosaur named from Mendoza Province, Argentina.

Mitsukurinidae

Mitsukurinidae is a family of sharks with one living genus, Mitsukurina, and five fossil genera: Anomotodon, Protoscapanorhynchus, Pseudoscapanorhynchus and Scapanorhynchus, and Woellsteinia, though some taxonomists consider Scapanorhynchus to be a synonym of Mitsukurina. The only known living species is the goblin shark, Mitsukurina owstoni.

This family of sharks is named in honour of Kakichi Mitsukuri who bought the holotype of the only species in this family to David Starr Jordon to be scientifically described.The most distinctive characteristic of the goblin sharks is the long, trowel-shaped, beak-like snout, much longer than those of other sharks. The snout contains sensory organs to detect the electrical signals given off by the shark's prey. They also possess long, protrusible jaws. When the jaws are retracted, the shark resembles a grey nurse shark, Carcharias taurus, with an unusually long nose. Its nose resembles the nose of a goblin, which is how it received its name. These sharks have only been seen about 50 times since their discovery in 1897.

Muyelensaurus

Muyelensaurus is a genus of titanosaurian sauropod dinosaur from the Late Cretaceous of Argentina. It was more slender than other titanosaurs. Fossils have been recovered from the Portezuelo Formation in the Neuquén province of Patagonia. The type species is M. pecheni. The name Muyelensaurus first appeared in a 2007 paper by Argentine paleontologists Jorge Calvo of the Universidad Nacional del Comahue and Bernardo González Riga of the Laboratorio de Paleovertebrados, and Brazilian paleontologist Juan Porfiri of the Universidade Federal do Rio de Janeiro.

Nodosauridae

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Notocolossus

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Ornithomimidae

Ornithomimidae (meaning "bird-mimics") is a group of theropod dinosaurs which bore a superficial resemblance to modern ostriches. They were fast, omnivorous or herbivorous dinosaurs from the Cretaceous Period of Laurasia (now Asia and North America), though they have also been reported from the Wonthaggi Formation of Australia. The group first appeared in the Early Cretaceous.

Prochelidella

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P. argentinae Lapparent de Broin & de la Fuente 2001

P. cerrobarcinae De la Fuente et al. 2011

P. portezuelae De la Fuente 2003

Santonian

The Santonian is an age in the geologic timescale or a chronostratigraphic stage. It is a subdivision of the Late Cretaceous epoch or Upper Cretaceous series. It spans the time between 86.3 ± 0.7 mya (million years ago) and 83.6 ± 0.7 mya. The Santonian is preceded by the Coniacian and is followed by the Campanian.

Turonian

The Turonian is, in the ICS' geologic timescale, the second age in the Late Cretaceous epoch, or a stage in the Upper Cretaceous series. It spans the time between 93.9 ± 0.8 Ma and 89.8 ± 1 Ma (million years ago). The Turonian is preceded by the Cenomanian stage and underlies the Coniacian stage.At the beginning of the Turonian an anoxic event took place which is called the Cenomanian-Turonian boundary event or the "Bonarelli Event".

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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