Tiourarén_Formation
Tiourarén Formation
Geological Formation
The Tiourarén Formation is a geological formation in the Agadez Region of Niger whose strata were originally thought to be Early Cretaceous. However, re-interpretation of the sediments showed that they are probably Middle or Late Jurassic (Bathonian-Oxfordian) in age.[1][2] Other works suggested it reaches the Barremian.[3] It is the uppermost unit of the Irhazer Group. Dinosaur remains & other vertebrates are among the fossils that have been recovered from the formation.[4] Originally part of the "Argiles de l'Ihrazer", the Tiouaren Formation primarily comprises reddish to purple siltstones with occasional marls, limestones, and scarce channel sandstones.[1]
Quick Facts Type, Unit of ...
| Tiourarén Formation | |
|---|---|
| Stratigraphic range: Middle or Late Jurassic 170–145 Ma (Suggested post Bathonian, reaching either Oxfordian or even Barremian) | |
| Type | Geological formation |
| Unit of | Irhazer Group |
| Underlies | Tazolé Formation (Tegama Group) |
| Overlies | Irhazer Shale |
| Thickness | ~350 m (1,150 ft) |
| Lithology | |
| Primary | Siltstone, mudstone |
| Other | Sandstone, marl, limestone |
| Location | |
| Coordinates | 16.5°N 7.8°E / 16.5; 7.8 |
| Approximate paleocoordinates | 8.2°N 2.5°E / 8.2; 2.5 |
| Region | Agadez |
| Country |  Niger |
| Extent | Iullemmeden Basin |
| Type section | |
| Named for | Tiourarén hill, Agadez |
| Named by | Moody R.T.J. & Sutcliffe P.J.C. |
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The formation comprises reddish, almost solid mudstones, which also shows grey and white streaks, probably caused by alternating oxidative and reducing environments. Stromatolites are intermittently found in calcareous layers, while indications of semi-arid to arid conditions such as desiccation cracks and caliche horizons have been reported. The formation suggests a low-energy setting with expansive floodplains, temporary shallow lake development,and calcrete horizon interchanged with swamps, with seasonal flooding from a meandering, shallow river system dominated by overbanked silt. Many sandstone channels are composed of reworked sand grain-sized pebbles of mudstone, supporting the view of a predominantly low-relief environment.[2] This latter feature is suggested by the widespread occurrence freshwater ostracod accumulations and rarer unionid bivalve shells.[5]
The Early Cretaceous dating for the Tiouaren Formation was based on vertebrate fossil evidence, specially Mawsoniidae coelacanths (referred without evidence to Mawsonia lavocati), while other taxa like Hybodus? sp. and Lepidotes? sp., are either dubious or have a suggested wide temporal distribution and invertebrates (conchostracans and unionid bivalves), offer limited stratigraphic value.[1] Recent report of an ash bed and other potentially datable beds near fossil bearing horizons opens the possibility of a future age calibration.[6]
Color key
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Notes Uncertain or tentative taxa are in small text; |
Bivalves
More information Fishes, Genus ...
| Fishes | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | Location | Stratigraphic position | Material | Notes | Images |
| Adrarunio[7] | A. deserticus | Teguidda-n-Adrar | Lower Member | Shells | A Nakamuranaiadidae freshwater bivalve. One of the earliest known trigonioidoids | |
| Afrohyrioides[7] | A. jowikolensis |
|
Upper Member | Shells | An Unionidae Freshwater Bivalve | |
| Coactunio[7] | C. iguallalensis |
|
Upper Member | Shells | An Unionidae Freshwater Bivalve | |
| Paraheudeana[7] | P. soudanensis |
|
All Members | Shells | A Margaritiferidae Freshwater Bivalve | |
| Rostrunio[7] | R. lapparenti | KP-35, Zinder track | Upper Member | Shells | An Unionidae Freshwater Bivalve | |
| Saharella[7] | S. tedreftensis | Reg Tamesna | Upper Member | Shells | An Unionidae Freshwater Bivalve | |
| Tamesnella[7] | T. amatouensis |
|
Upper Member | Shells | A Tamesnelloidea Freshwater epifaunal substrate Bivalve | |
| Tamesnelloides[7] | T. lithoides | SE of In-Afer | Upper Member | Shells | A Tamesnelloidea Freshwater epifaunal substrate Bivalve | |
| Tegulaedon[7] | T. humei |
|
Upper Member | Shells | A Margaritiferidae Freshwater Bivalve | |
| Tuaregunio[7] | T. agadesensis | KP-35, Zinder track | Upper Member | Shells | An Unionidae Freshwater Bivalve | |
| Unionelloides[7] | U. globulosus |
|
Upper Member | Shells | An Unionidae Freshwater Bivalve | |
| U. (Phortunio) giganteus | 10 km E of In-Abangarit | |||||
| U. bellalensis | 35 km NE of Mount Bellal | Upper Member | Shells | |||
| Unionida[7] | Indet A | Reg Tamesna | All Members | Shells | Indeterminate Unionid Freshwater Bivalves | |
| Indet. B | Teguidda-n-Adrar | |||||
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Fishes
More information Fishes, Genus ...
| Fishes | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | Location | Stratigraphic position | Material | Notes | Images |
| Asiatoceratodus[1][8] | A. tiguidensis |
|
Upper Member | Isolated tooth plates & other remains | An Asiatoceratodontidae Lungfish | |
| Ceratodus[9] | C. sp. | Tuiguidit foreland | Upper Member | tooth plates | A Ceratodontidae Lungfish | |
| Holostei[9] | Indeterminate | Tuiguidit foreland | Upper Member | "scales of ganoid fishes" | Indeterminate fish remains | |
| Hybodus?[1] | H.? spp. |
|
Upper Member | Teeth | A Hybodontiform Chondrichthyan | |
| Mawsoniidae[1][10] | Indeterminate | Upper Member | Teeth, isolated scales & partially articulated remains of the caudal fin | A Coelacanth, previously referred to Mawsonia | ||
| Lepidotes?[1] | L. spp. | Upper Member | Isolated scales | A Lepisosteiformes bony fish | ||
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Testudinata
"Turtle Bones" where quoted in the OR description of the unit.[5]
More information Turtles, Genus ...
| Turtles | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | Location | Stratigraphic position | Material | Notes | Images |
|
Indeterminate |
Irhazer Plain |
Upper Member |
Isolated Egg |
Based on the "small size, spherical shape, and small pores" was suggested it belonged to a turtle |
||
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Crocodrylomorphs
"Crocodiles" where quoted in the OR description of the unit.[5]
More information Crocodrylomorphs, Genus ...
| Crocodrylomorphs | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | Location | Stratigraphic position | Material | Notes | Images |
| Crocodylomorpha[9] | Indeterminate | Tuiguidit foreland | Upper Member | teeth, osteoderms | Indeterminate crocodrylomorph remains | |
| Goniopholididae[12] | Gen et sp. nov A | Irhazer Plain | Upper Member | Complete skull | The first African goniopholidids, suggesting connections with Laurasia | |
| Gen et sp. nov B | Irhazer Plain | Upper Member | Narrow cranium with elongated snout | |||
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Avemetarsalia
"Rare (in abundance) Pterosaurs" where quoted in the OR description of the unit.[5]
More information Dinosaurs, Genus ...
| Dinosaurs | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | Location | Stratigraphic position | Material | Notes | Images |
| Afrovenator[13][14] |
|
|
Upper Member |
|
An Afrovenatorinae Megalosauroidean | |
| Averostra[14] | Indeterminate | NE of Tadibene | Upper Member | TP4-6; TP4-7, Isolated teeth | An indeterminate Theropod | |
| Ceratosauria[14] | Indeterminate | NE of Tadibene | Upper Member | TP4-4, isolated teeth | An indeterminate Ceratosaur | |
| Eusauropoda[6] | Gen et sp. nov | Irhazer Plain | Lower Member | Skull and multiple articulated postcranial skeletons | A notoriously complete taxon with stocky proportions, robust skull and short neck | |
| Jobaria[15] | J. tiguidensis |
|
Upper Member | "Skull [and] several skeletons." | A Sauropod, maybe an Eusauropod. Among the most abundant terrestrial vertebrates in the formation | |
| Megalosauridae[14] | Indeterminate | NE of Tadibene | Upper Member | TP4-5, TP4-8, TP4-10, teeth | An indeterminate Megalosaur | |
|
"R." tamesnensis[13] |
Tamerát, Agadez |
Upper Member |
dorsal vertebrae and scapula |
An Indeterminate Sauropod, also reported from younger Cretaceous beds, representing likely different taxa. |
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| Sauropoda[17][9] | Indeterminate |
|
Upper Member |
|
Indeterminate or unnamed Sauropod remains | |
|
Indeterminate |
NE of Tadibene |
Upper Member |
TP4-2, TP4-3 , teeth |
Referred to Spinosaurs, can be of ceratosaur origin instead |
||
| Spinostropheus[18] | S. gautieri |
|
Upper Member | (many individuals) cervical, dorsal, posterior dorsal & caudal vertebra, four dorsal, three sacral & two caudal fragments, partial left humerus, ulna, distal right pubis, distal femur, incomplete right tibia, distal fibula incomplete fibula, proximal metatarsals, four metatarsal fragments, pedal phalangeal fragments, pedal phalanx (single individual), three manual unguals[19] | Either a basal Ceratosaurian, a basal Abelisauroidean or even a Noasaur | |
| Thyreophora[20] | Gen et sp. nov | Abaka, Agadez | Upper Member | "Associated, but disarticulated, bones, teeth, and abundant scutes from many individuals ranging in maturity from subadult to adult" | A basal thyreophoran, suggested to be related to Scutellosaurus. A relatively common taxon, with a bonebed of up to twenty individuals.[10] | |
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- Rauhut, Oliver W.M.; López-Arbarello, Adriana (2009). "Considerations on the age of the Tiouaren Formation (Iullemmeden Basin, Niger, Africa): Implications for Gondwanan Mesozoic terrestrial vertebrate faunas". Palaeogeography, Palaeoclimatology, Palaeoecology. 271 (3–4): 259–267. doi:10.1016/j.palaeo.2008.10.019. ISSN 0031-0182.
- Tuiguidit foreland at Fossilworks.org
- Le Loeuff, J.; Läng, E.; Cavin, L.; Buffetaut, E. (2012). "Between Tendaguru and Bahariya: on the age of the Early Cretaceous dinosaur sites from the Continental Intercalaire and other African formations" (PDF). Journal of Stratigraphy. 36 (486): 584–601.
- Weishampel, David B; et al. (2004). "Dinosaur distribution (Early Cretaceous, Africa)." In: Weishampel, David B.; Dodson, Peter; and Osmólska, Halszka (eds.): The Dinosauria, 2nd, Berkeley: University of California Press. Pp. 571-573. ISBN 0-520-24209-2.
- Moody, R.T.J.; Sutcliffe, P.J.C. (1991). "The Cretaceous deposits of the Iullemmeden Basin of Niger, central West Africa". Cretaceous Research. 12 (2): 137–157. doi:10.1016/s0195-6671(05)80021-7. ISSN 0195-6671.
- Vidal, Daniel; Sereno, Paul C.; Myhrvold, Nathan (2023). "Temporal Sequence And Diversity Of Sauropod Dinosaurs In The Middle To Late Jurassic Irhazer Series Of Niger" (PDF). SVP 2023 PROGRAM GUIDE. 83rd Annual Meeting. 83 (1): 433–434.
- Van Damme, Dirk; Bogan, Arthur E.; Dierick, Manuel (2015). "A revision of the Mesozoic naiads (Unionoida) of Africa and the biogeographic implications". Earth-Science Reviews. 147: 141–200. doi:10.1016/j.earscirev.2015.04.011. ISSN 0012-8252.
- López-Arbarello, A.; Rauhut, O. W.; Moser, K. (2008). "Jurassic fishes of Gondwana". Revista de la Asociación Geológica Argentina. 63 (4): 586–612. Retrieved 29 July 2022.
- Witzmann, Florian; Hampe, Oliver; Rothschild, Bruce M.; Joger, Ulrich; Kosma, Ralf; Schwarz, Daniela; Asbach, Patrick (2016-01-25). "Subchondral cysts at synovial vertebral joints as analogies of Schmorl's nodes in a sauropod dinosaur from Niger". Journal of Vertebrate Paleontology. 36 (2): e1080719. doi:10.1080/02724634.2016.1080719. ISSN 0272-4634.
- DeVries, Raina; Sereno, Paul; Gamonal, Arturo; Fontela, Noelia (2023). "Small-Bodied Armored Dinosaur From Niger (Irhazer Series: Tiourarén Formation) Documents The Basal Acquisition Of Quadrupedal Posture And Subadult Herding Behavior Among Thyreophorans (Dinosauria: Ornithischia)" (PDF). SVP 2023 Program Guide. 83 (1): 143–144.
- Mezak, Curren K; Choi, Seung (2021). "Using Ebsd For The Identification Of A Fossilized Egg Found In The Middle Jurassic Tiouraren Formation Of Niger, Africa". SVPA 81st Annual Meeting. 81 (1): 188.
- Pol, D.; Sereno, P.C. (2019). "New Jurassic and Cretaceous neosuchians from the Sahara add to Africa´s remarkable crocodyliform diversity and its paleogeographic connection with northern landmasses". Congreso; 79° Annual Meeting of the Society of Vertebrate Paleontology. 79 (1): 171.
- Sereno, P.C.; Wilson, J.A.; Larsson, H.C.; Dutheil, D.B.; Sues, H.D. (1994). "Early cretaceous dinosaurs from the Sahara". Science. 266 (5183): 267–271. doi:10.1126/science.266.5183.267. PMID 17771449. S2CID 36090994.
- Serrano-Martínez, Alejandro; Ortega, Francisco; Sciscio, Lara; Tent-Manclús, José Enrique; Fierro Bandera, Ignacio; Knoll, Fabien (2015). "New theropod remains from the Tiourarén Formation (?Middle Jurassic, Niger) and their bearing on the dental evolution in basal tetanurans". Proceedings of the Geologists' Association. 126 (1): 107–118. doi:10.1016/j.pgeola.2014.10.005. ISSN 0016-7878.
- Sereno, Paul C.; Beck, Allison L.; Dutheil, Didier B.; Larsson, Hans C. E.; Lyon, Gabrielle H.; Moussa, Bourahima; Sadleir, Rudyard W.; Sidor, Christian A.; Varricchio, David J.; Wilson, Gregory P.; Wilson, Jeffrey A. (1999-11-12). "Cretaceous Sauropods from the Sahara and the Uneven Rate of Skeletal Evolution Among Dinosaurs". Science. 286 (5443): 1342–1347. doi:10.1126/science.286.5443.1342. ISSN 0036-8075. PMID 10558986.
- Olshevsky, G. (1995-03-24). "African Dinosaur Discoveries". Science. 267 (5205): 1750. doi:10.1126/science.267.5205.1750. ISSN 0036-8075. PMID 17775786.
- Lapparent, A. F. d. (1960). "Les Dinosauriens du "Continental intercalaire" du Saharal central [The dinosaurs of the "Continental Intercalaire" of the central Sahara]". Mémoires de la Société géologique de France, nouvelle série (A). 39 (88): 1–57.
- Sereno, Paul C.; Wilson, Jeffrey A.; Conrad, Jack L. (2004-07-07). "New dinosaurs link southern landmasses in the Mid–Cretaceous". Proceedings of the Royal Society of London. Series B: Biological Sciences. 271 (1546): 1325–1330. doi:10.1098/rspb.2004.2692. ISSN 0962-8452. PMC 1691741. PMID 15306329.
- Souza-Júnior, André Luis de; Candeiro, Carlos Roberto dos Anjos; Vidal, Luciano da Silva; Brusatte, Stephen Louis; Mortimer, Mickey (2023-07-05). "Abelisauroidea (Theropoda, Dinosauria) from Africa: a review of the fossil record". Papéis Avulsos de Zoologia. 63: e202363019. doi:10.11606/1807-0205/2023.63.019. ISSN 1807-0205.
- Ridgwell, Nicole; Sereno, Paul (2010). "A basal Thyreophoran (Dinosauria, Ornithischia) from the Tiouraren Formation of Niger". 70th Anniversary Meeting of the Society of Vertebrate Paleontology, Program and Abstracts. Society of Vertebrate Paleontology: 150A–151A.
- A. F. d. Lapparent. 1960. Les Dinosauriens du "Continental intercalaire" du Saharal central [The dinosaurs of the "Continental Intercalaire" of the central Sahara]. Mémoires de la Société géologique de France, nouvelle série 39(88A):1-57
- P. C. Sereno, A. L. Beck, D. B. Dutheil, H. C. E. Larsson, G. H. Lyon, B. Moussa, R. W. Sadleir, C. A. Sidor, D. J. Varricchio, G. P. Wilson, and J. A. Wilson. 1999. Cretaceous sauropods from the Sahara and the uneven rate of skeletal evolution among dinosaurs. Science 286:1342-1347
- P. C. Sereno, J. A. Wilson, H. C. E. Larsson, D. B. Dutheil, and H.-D. Sues. 1994. Early Cretaceous dinosaurs from the Sahara. Science 266(5183):267-271
- F. Witzmann, O. Hampe, B. M. Rothschild, U. Joger, R. Kosma, D. Schwarz, and P. Asbach. 2016. Subchondral cysts at synovial vertebral joints as analogies of Schmorl's Nodes in a sauropod dinosaur from Niger. Journal of Vertebrate Paleontology 36(2):e1080719:1-11