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]

Turonian
93.9 – 89.8 ± 0.3 Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓
Paleogeography of the late Turonian (90 Ma), showing the high sea level at the time
Chronology
Key events in the Cretaceous -140 — – -130 — – -120 — – -110 — – -100 — – -90 — – -80 — – -70 — – M e s o z o i c C Z J C r e t a c e o u s P g L J E a r l y L a t e P C Tithonian Berriasian Valanginian Hauterivian Barremian Aptian Albian Cenoman. Turonian Coniacian Santonian Campanian Maastricht. Danian       ← K-Pg mass extinction An approximate timescale of key Cretaceous events. Axis scale: millions of years ago.
Etymology
Name formality	Formal
Usage Information
Celestial body	Earth
Regional Usage	Global (ICS)
Time scale(s) used	ICS Time Scale
Definition
Chronological unit	Age
Stratigraphic unit	Stage
Time span formality	Formal
Lower boundary definition	FAD of the Ammonite Watinoceras devonense
Lower boundary GSSP	Rock Canyon, Colorado, USA 38.2822°N 104.7275°W
GSSP ratified	September 2003[1]
Upper boundary definition	Not formally defined
Upper boundary definition candidates	FAD of the Inoceramid Bivalve Cremnoceramus rotundatus
Upper boundary GSSP candidate section(s)	Słupia Nadbrzeżna, Poland Pueblo, Colorado, USA Salzgitter-Salder quarry, Germany

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:

• zone of Subprionocyclus neptuni (in the Upper Turonian)
• zone of Collignoniceras woollgari (in the Middle Turonian)
• zone of Mammites nodosoides
• zone of Watinoceras coloradoense or Watinoceras devonense (last two both in the Lower Turonian)

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
Maleevus		Mongolia		Talarurus
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	An informally named abelisauroid ceratosaur.	Mapusaurus Nothronychus Timurlengia
Enigmosaurus		Khara Khutul, Mongolia	A therizinosaur.
Erlikosaurus		Bayan Shireh Formation of Mongolia	A therizinosaur.
Mapusaurus		Huincul Formation, Argentina	A gigantic carcharodontosaurid carnosaur.
Nothronychus		New Mexico, USA	A therizinosaur.
Segnosaurus	Albian to Coniacian Ages	Khan-Bogdsomona, Mongolia	A large therizinosaur and one the first described.
Timurlengia		Kyzylkum Desert, Uzbekistan	A small (250 kg) tyrannosauroid.
Urbacodon		Uzbekistan	A troodontid.
Xenotarsosaurus		Bajo Barreal Formation, Chubut Province, Argentina	A medium-sized abelisaurid ceratosaur.
Suskityrannus		New Mexico	A small basal tyrannosauroid.

References

1. Kennedy, W. J.; I. Walaszczyk; W. A. Cobban (2005). "The Global Boundary Stratotype Section and Point for the base of the Turonian Stage of the Cretaceous: Pueblo, Colorado, U.S.A." (PDF). Episodes. 28 (2): 93–104. doi:10.18814/epiiugs/2005/v28i2/003.
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.

External links

• GeoWhen Database - Turonian
• Late Cretaceous timescale, at the website of the subcommission for stratigraphic information of the ICS
• Stratigraphic charts of the Cretaceous: and , at the website of Norges Network of offshore records of geology and stratigraphy
• Turonian Microfossils: 48 images of Foraminifera