Orbitolina

Orbitolina; Temporal range: Aptian-Cenomanian; ~125–95 Ma PreꞒ Ꞓ O S D C P T J K Pg N
Scientific classification
Domain:	Eukaryota
Clade:	Diaphoretickes
Clade:	SAR
Phylum:	Retaria
Subphylum:	Foraminifera
Class:	Globothalamea
Order:	Textulariida
Family:	†Orbitolinidae
Subfamily:	†Orbitolininae
Genus:	†Orbitolina; Lamarck 1816
Species
	Orbitolina concava Lamarck, 1816; O. discoideaconoidea Gras, 1852; O. lenticulata Lamarck, 1816

Orbitolina is an extinct genus of foraminifera belonging to the order Textulariida and family Orbitolinidae. Fossils of this genus are widely found in beds deposited in the Tethys Ocean ranging from Aptian (early Cretaceous))^[4] to Cenomanian (early Late Cretaceous) in age.^[3] It has been used as a shallow carbonate platform facies marker^[4] and as a Cretaceous index fossil.^[3]

The test of the organism has the shape of a cone, with the proloculus (initial chamber) at the apex of the cone and increasingly large cuplike chambers forming the remainder of the test. Each chamber is further subdivided by numerous partitions.^[3]

References

^ Schlagintweit, F.; Wagreich, M. (2005). "Micropaleontology of "Orbitolina Beds" of Lower Austria (Branderfleck Formation, Lower Cenomanian)" (PDF). Jahbruch der Geologischen Bundenstalt. 145 (1): 115–125. Retrieved 25 October 2021.
^ Buckman, J. O. (March 1997). "An unusual new trace fossil from the Lower Carboniferous of Ireland: Intexalvichnus magnus". Journal of Paleontology. 71 (2): 316–324. doi:10.1017/S0022336000039226.
^ ^a ^b ^c ^d Douglass, R.C. (1960). "The Foraminiferal Genus Orbitolina in North America". United States Geological Survey Professional Paper. Professional Paper. 333. doi:10.3133/pp333.
^ ^a ^b Vilas, Lorenzo; Masse, Jean Pierre; Arias, Consuelo (December 1995). "Orbitolina episodes in carbonate platform evolution: the early Aptian model from SE Spain" (PDF). Palaeogeography, Palaeoclimatology, Palaeoecology. 119 (1–2): 35–45. Bibcode:1995PPP...119...35V. doi:10.1016/0031-0182(95)00058-5.

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[1] Schlagintweit, F.; Wagreich, M. (2005). "Micropaleontology of "Orbitolina Beds" of Lower Austria (Branderfleck Formation, Lower Cenomanian)" (PDF). Jahbruch der Geologischen Bundenstalt. 145 (1): 115–125. Retrieved 25 October 2021.

[2] Buckman, J. O. (March 1997). "An unusual new trace fossil from the Lower Carboniferous of Ireland: Intexalvichnus magnus". Journal of Paleontology. 71 (2): 316–324. doi:10.1017/S0022336000039226.

[Douglass-3] Douglass, R.C. (1960). "The Foraminiferal Genus Orbitolina in North America". United States Geological Survey Professional Paper. Professional Paper. 333. doi:10.3133/pp333.

[VilasMasseArias-4] Vilas, Lorenzo; Masse, Jean Pierre; Arias, Consuelo (December 1995). "Orbitolina episodes in carbonate platform evolution: the early Aptian model from SE Spain" (PDF). Palaeogeography, Palaeoclimatology, Palaeoecology. 119 (1–2): 35–45. Bibcode:1995PPP...119...35V. doi:10.1016/0031-0182(95)00058-5.

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