Dukamaje Formation

The Dukamaje Formation is a geological formation in Niger whose strata date back to the Late Cretaceous. Dinosaur remains are among the fossils that have been recovered from the formation.[1] A wealth of Mosasaur fossils have also been recovered from this formation, particularly from the area around Mt. Igdaman.[2]

Dukamaje Formation Stratigraphic range: Maastrichtian[1]
Type	Geological formation
Sub-units	Gypsiferous shale Member
Lithology
Primary	Mudstone, shale
Other	Siltstone, marl, gypsum
Location
Coordinates	15.4°N 5.8°E
Approximate paleocoordinates	5.1°N 0.6°E
Region	Tahoua Sokoto
Country	Niger  Nigeria
Extent	Iullemmeden Basin
Type section
Named for	Dukamaje, Sokoto, Nigeria
Dukamaje Formation (Niger)

Fossil content

Dinosaurs of the Dukamaje Formation
Taxa	Presence	Description	Images
Genus: ?Bahariasaurus[1] ?B. ingens.[1]	Geographically present in Département De Tahoua, Niger.[1]

Mosasaurs of the Dukamaje Formation
Taxa	Presence	Description	Images
Genus: Igdamanosaurus[2] I. aegyptiacus[2]	Geographically present on Mt. Igdaman, near the village of Igdaman (or In Daman).[2]	Mid-sized globidensine mosasaur.[3] Originally described as a plioplatecarpine. Durophagous.[2]	Goronyosaurus and juvenile elasmosaurs
Genus: Goronyosaurus[2] G. nigeriensis G. sp.[2]	Type locality unknown. From the portion of the Dukamaje Formation located in Nigeria. Geographically present on Mt. Igdaman. From the portion of the Dukamaje Formation located in Niger.[2]	Large mosasaur of uncertain affiliations. High number of foramina on the snout and small eyes indicate a murky-water hunter.[4]
Genus: ?Angolasaurus[2] ?A. sp.[2]	Geographically present on Mt. Igdaman.[2]	Represented here by four vertebrae, one from a juvenile. Fragmentary state makes identification difficult.[2]
Genus: Halisaurus[2] H. sp.[2]	Geographically present on Mt. Igdaman.[2]	Mid-sized mosasaur. Represented here by four vertebrae.[2]
Genus: Plioplatecarpus[2] P. sp.[2]	Geographically present on Mt. Igdaman.[2]	Mid-sized plioplatecarpine mosasaur. Represented here by several vertebrae.[2]
Genus: Platecarpus[2] P. sp.[2]	Geographically present on Mt. Igdaman.[2]	Mid-sized plioplatecarpine mosasaur. Represented here by a single fragmentary vertebrae.[2]
Genus: Mosasaurus[2] cf. M. hoffmannii[2]	Geographically present on Mt. Igdaman.[2]	Massive mosasaurine mosasaur. Represented here by a fragmentary tooth crown. The first example of Mosasaurus from Niger and Nigeria.[2]

Other reptiles

• Sokotosuchus ianwilsoni[5]
• Palaeophis sp.[6]
• Podocnemis sp.
• Trematochampsa taqueti
• Libycosuchus sp.

Fishes

• Asteracanthus aegyptiacus[7]
• Igdabatis sigmodon
• Lamna nigeriana
• Schizorhiza stromeri
• Stephanodus lybicus
• Stratodus apicalis
• Ischyrhiza nigeriensis
• Ceratodus sp.
• Ginglymostoma sp.
• Pycnodus sp.

See also

• List of dinosaur-bearing rock formations
• Lists of fossiliferous stratigraphic units in Africa
  • List of fossiliferous stratigraphic units in Niger
• Geology of Niger
• Geology of Nigeria

References

1. Weishampel, David B; et al. (2004). "Dinosaur distribution (Late Cretaceous, Africa)." In: Weishampel, David B.; Dodson, Peter; and Osmólska, Halszka (eds.): The Dinosauria, 2nd, Berkeley: University of California Press. Pp. 604-605. ISBN 0-520-24209-2.
2. Lingham-Soliar, Theagarten (1991). "Mosasaurs from the upper Cretaceous of Niger". Palaeontology. 34: 653–670.
3. Lindgren, Johan (2005). "Dental and vertebral morphology of the enigmatic mosasaur Dollosaurus (Reptilia, Mosasauridae) from the lower Campanian (Upper Cretaceous) of southern Sweden". Bulletin of the Geological Society of Denmark.
4. "Tongues, venom glands, and the changing face of Goronyosaurus". Tetrapod Zoology. Retrieved 2017-01-11.
5. Gilbedi Hills, Rima River at Fossilworks.org
6. Mont Igdaman (bed 25) at Fossilworks.org
7. In Touhout (bed 4) at Fossilworks.org

Further reading

• R. T. J. Moody and P. J. C. Suttcliffe. 1991. The Cretaceous deposits of the Iullemmeden Basin of Niger, central West Africa. Cretaceous Research 12:137-157