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.[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]

At the beginning of the Turonian an anoxic event took place which is called the Cenomanian-Turonian boundary event or the "Bonarelli Event".

Stratigraphic definition
Lithographic limestone from the Gerofit Formation (Turonian) north of Makhtesh Ramon, southern Israel; a variety of Jerusalem stone (meleke).

The Turonian (French: Turonien) was defined by the French paleontologist Alcide d'Orbigny (1802–1857) in 1842. Orbigny named it after the French city of Tours in the region of Touraine (department Indre-et-Loire), which is the original type locality.

The base of the Turonian stage is defined as the place where the ammonite species Wutinoceras devonense first appears in the stratigraphic column. The official reference profile (the GSSP) for the base of the Turonian is located in the Rock Canyon anticline near Pueblo, Colorado (United States, coordinates: 38° 16' 56" N, 104° 43' 39" W).[3]

The top of the Turonian stage (the base of the Coniacian) is defined as the place in the stratigraphic column where the inoceramid bivalve species Cremnoceramus rotundatus first appears.

Subdivision

The Turonian is sometimes subdivided in Lower/Early, Middle and Upper/Late substages or subages. In the Tethys domain, it contains the following ammonite biozones:

Other important index fossils are species of the inoceramid genus Inoceramus (I. schloenbachi, I. lamarcki and I. labiatus). Inoceramids are bivalve Mollusca related to today's mussels.

Palaeontology

Ankylosaurs
Ankylosaurs of the Turonian
Taxa Presence Location Description Images
Mongolia
Talarurus
Bayan Shireh Formation, Mongolia

Avialans
Avialans of the Turonian
Taxa Presence Location Description Images

Catenoleimus

 Bissekty Formation, Uzbekistan A mid-sized enantiornithine, perhaps 20–25 cm long in life
Ichthyornis

Explorornis

 Bissekty Formation, Uzbekistan

Ichthyornis

 Turonian - Campanian Alberta and Saskatchewan, Canada; Alabama, Kansas, New Mexico and Texas, USA; Argentina; Central Asia The Cretaceous ecological equivalent of modern seabirds such as gulls, petrels, and skimmers. At 60 cm (2.0 ft), it was the size of a gull. Although the wings and breastbone are very modern in appearance (suggesting strong flight ability), the jaws retained numerous small, sharp teeth

Ceratopsians
Ceratopsia of the Turonian
Taxa Presence Location Description Images

Zuniceratops

 Moreno Hill Formation, New Mexico, USA The earliest-known ceratopsian to have eyebrow horns and the oldest-known ceratopsian from North America, appears to have been roughly 3 to 3.5 meters (9.8 to 11.5 ft) long and 1 meter (3.3 feet) tall at the hips.
Zuniceratops

Crocodylomorphs
Crocodylomorpha of the Turonian
Taxa Presence Location Description Images

Baurusuchus

 Brazil
Baurusuchus

Montealtosuchus

 Turonian to Santonian Adamantina Formation, São Paulo, Brazil A terrestrial peirosaurid

Stratiosuchus

 Brazil

Tadzhikosuchus

 Fergana Basin, Tajikistan; Bissekty Formation, Dzharakhuduk, Uzbekistan An early alligatoroid very similar to Diplocynodon from the Cenozoic.

Mammals
Mammalia of the Turonian
Taxa Presence Location Description Images

Bryceomys

 Straight Cliffs Formation of Utah, US. Smaller than a mouse, thought to behave somewhat similar.

Ornithopods
Ornithopoda of the Turonian
Taxa Presence Location Description Images

Anabisetia

 Cerro Lisandro Formation, Neuquén Province, Patagonia, Argentina A 2 metres (6.6 ft) long elasmarian
Anabisetia
Bactrosaurus

Bactrosaurus

 Turonian to Coniacian Gobi Desert, Mongolia and China Would have been 6 m (20 ft) long[1] and 2 m (6.6 ft) high when in the quadrupedal stance, and weighed 1,100–1,500 kg (2,400–3,300 lb). Like many hadrosaurs, it could switch between bipedal and quadrupedal stances, but unusually it had large spines protruding from the vertebrae.
Jeyawati Turonian Moreno Hill Formation, New Mexico A basal hadrosauroid

Macrogryphosaurus

 Turonian to early Coniacian Portezuelo Formation, Argentina A genus of basal iguanodont, a large bipedal herbivore

Notohypsilophodon

 Cenomanian-Turonian Bajo Barreal Formation, Chubut, Argentina A hypsilophodontid or other basal ornithopod, Notohypsilophodon would have been a bipedal herbivore. Its size has not been estimated

Shuangmiaosaurus

 Cenomanian-Turonian China A poorly known iguanodont

Plesiosaurs
Plesiosauria of the Turonian
Taxa Presence Location Description Images

Brachauchenius

 Ottawa County, Kansas Brachauchenius represents the last known occurrence of a pliosaur in North America.
Libonectes
Polyptychodon
Thililua

Libonectes

 Britton Formation (Cedar Hill), Texas, USA A 7–14 m (23–46 ft) long creature, was very similar to the related Elasmosaurus. It had a compact body with a short tail and large flippers. Its small skull had long, forward-facing teeth ideal for catching slippery fish and squid that came together outside of its mouth when the mouth was closed, and was placed atop a very long neck.

Manemergus

 Morocco A genus of polycotylid plesiosaur

Megacephalosaurus

 Carlile Shale, Russell County, Kansas

Polyptychodon hudsoni

 Texas, USA A 10 metres (33 ft) long Brachaucheniin pliosaurid

Thililua

 High Atlas, Morocco A genus of polycotylid plesiosaur, the estimated total length of Thililua is 5.5 to 6 metres.

Pterosaurs
Pterosaurs of the Turonian
Taxa Presence Location Description Images

Lonchodectes

 Upper Chalk, Kent, England

Lonchodraco

 Albian-Turonian Chalk Formation, Kent and Cambridge Greensand, England

Squamatans
Squamata of the Turonian
Taxa Presence Location Description Images

Dallasaurus

 Arcadia Park Shale, Texas, USA A basal, small, plesiopedal mososauroid

Russellosaurus

 Arcadia Park Shale, Texas, USA A basal, small, lightly built mosasaur

Theropods (non-avialan)
Theropods of the Turonian
Taxa Presence Location Description Images
  • Bayosaurus
 Neuquén, Argentina
Mapusaurus
Nothronychus
Timurlengia
Khara Khutul, Mongolia
Bayan Shireh Formation of Mongolia
Huincul Formation, Argentina
New Mexico, USA
Khan-Bogdsomona, Mongolia
Kyzylkum Desert, Uzbekistan A small (250 kg) tyrannosauroid.
Uzbekistan
Bajo Barreal Formation, Chubut Province, Argentina
New Mexico
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References
  1. Super User. "ICS - Chart/Time Scale". www.stratigraphy.org.
  2. See Gradstein et al. (2004) for a detailed description of the ICS' timescale
  3. The GSSP was established by Kennedy et al. (2005)

Literature
  • Gradstein, F.M.; Ogg, J.G. & Smith, A.G.; 2004: A Geologic Time Scale 2004, Cambridge University Press.
  • Kennedy, W.J.; Walaszczyk, I. & Cobban, W.A.; 2005: The Global Boundary Stratotype Section and Point for the base of the Turonian Stage of the Cretaceous: Pueblo, Colorado, U.S.A., Episodes 28(2): pp 93–104.
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