Elrhaz Formation

The Elrhaz Formation is a geological formation in Niger, central Africa.

Elrhaz Formation
Stratigraphic range: Aptian-Albian
~112 Ma
Outcrops of the formation near Gadoufaoua
TypeGeological formation
Unit ofTegama Group
UnderliesEchkar Formation
OverliesTazolé Formation
Coordinates16.8°N 9.5°E / 16.8; 9.5
Approximate paleocoordinates3.1°N 4.9°E / 3.1; 4.9
Country Niger
ExtentTenere desert

Its strata date back to the Early Cretaceous (late Aptian to early Albian stages, about 112 million years ago). Dinosaur remains are among the fossils that have been recovered from the formation, alongside those of multiple species of crocodyliformes.


Gadoufaoua (Touareg for "the place where camels fear to go") is a site within the Elrhaz Formation (located at 16°50′N 9°25′E) in the Tenere desert of Niger known for its extensive fossil graveyard. It is where remains of Sarcosuchus imperator, popularly known as SuperCroc, were found (by Paul Sereno in 1997, for example), including vertebrae, limb bones, armor plates, jaws, and a nearly complete 6 feet (1.8 m) skull.

Gadoufaoua is very hot and dry. However, it is supposed that millions of years ago, Gadoufaoua had trees, plants and wide rivers. The river covered the remains of dead animals, the fossilized remains of which were protected by the drying rivers over millions of years.[1]

Vertebrate paleofauna

Fossils of the turtle Taquetochelys decorata were found in the formation.[2]


Crocodyliformes reported from the Elrhaz Formation
Genus Species Material Notes Images


A. wegeneri[3]


"nearly complete skull" - Sereno & Larsson (1999)

Pseudonym. Dog-Croc


A. minor[3]


"nearly complete skull" - Sereno & Larsson (1999)

Pseudonym. Duck-Croc
Sarcosuchus[4] S. imperator "partial skeletons, numerous skulls" (1966)


Ornithischians reported from the Elrhaz Formation
Genus Species Stratigraphic position Material Notes Images


L. arenatus[3]


"Partial skull, fragmentary postcranial skeleton."[5]


O. nigeriensis[3]


"Skull and poscrania, second skeleton."[6]


E. nigeriensis[3]



A dryosaurid


Theropods reported from the Elrhaz Formation
Genus Species Stratigraphic position Material Notes Images
Afromimus A. tenerensis (2017) "caudal vertebrae, chevrons and portions of the right hind limb"[8] An Ornithomimosaur


E. dinops[9]


"Partial skull and postcranial remains."[10]



S. tenerensis[3]


Partial skull and associated skeleton.[11]

A second, possible spinosaurid found in the formation, Cristatusaurus, is considered either a separate species or a synonym to Suchomimus[12]


K. palaios[3]


Postcranial skeleton and partial skull.[13]



Sauropods reported from Elrhaz Formation
Genus Species Material Images
Nigersaurus N. taqueti The limited understanding of the genus was the result of poor preservation of its remains, which arises from the delicate and highly pneumatic construction of the skull and skeleton, in turn causing disarticulation of the fossils. Some of the skull fossils were so thin that a strong light beam was visible through them. Therefore, no intact skulls or articulated skeletons have been found, and these specimens represent the most complete known rebbachisaurid remains.

See also


  1. SCIENCE IN THE NEWS - Nov. 13: Digest - 12 November 2001 Voice of America
  2. Laganemys type, Gadoufaoua at Fossilworks.org
  3. "68.1 Departement D'Agedez, Niger; 1. Elrhaz Formation," in Weishampel, et al. (2004). Page 572
  4. Sereno et al., 2011
  5. "Table 19.1," in Weishampel, et al. (2004). Page 416.
  6. "Table 19.1," in Weishampel, et al. (2004). Page 417.
  7. "Table 19.1," in Weishampel, et al. (2004). Page 415.
  8. Sereno, P. (2017). "Early Cretaceous ornithomimosaurs (Dinosauria: Coelurosauria) from Africa". Ameghiniana. 54 (5): 576–616. doi:10.5710/AMGH.23.10.2017.3155.
  9. Sereno & Brusatte, 2008
  10. "Table 4.1," in Weishampel, et al. (2004). Page 73.
  11. "Table 4.1," in Weishampel, et al. (2004). Page 72.
  12. Rauhut, O.W.M. (2003). "The interrelationships and evolution of basal theropod dinosaurs". Special Papers in Palaeontology 69: 1-213.
  13. "Table 4.1," in Weishampel, et al. (2008). Page 72.


  • Sereno, P. C.; H. C. Larsson; C. A. Sidor, and B. Gado. 2001. The giant crocodyliform Sarcosuchus from the Cretaceous of Africa. Science 294. 1516–1519. doi:10.1126/science.1066521ISSN 0036-8075PMID 11679634
  • Sereno, Paul C., and Stephen L. Brusatte. 2008. Basal abelisaurid and carcharodontosaurid theropods from the Lower Cretaceous Elrhaz Formation of Niger. Acta Palaeontologica Polonica 53. 15–49. Accessed 2018-10-06.
  • Weishampel, David B.; Dodson, Peter; and Osmólska, Halszka (eds.): The Dinosauria, 2nd, Berkeley: University of California Press. 861 pp. ISBN 0-520-24209-2

Further reading

  • P. M. Galton and P. Taquet. 1982. Valdosaurus, a hypsilophodontid dinosaur from the Lower Cretaceous of Europe and Africa. Géobios 15(2):147-159
  • H. C. E. Larsson and B. Gado. 2000. A new Early Cretaceous crocodyliform from Niger. Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen 217(1):131-141
  • P. C. Sereno and S. J. ElShafie. 2013. A New Long-Necked Turtle, Laganemys tenerensis (Pleurodira: Araripemydidae), from the Elrhaz Formation (Aptian–Albian) of Niger. In D. B. Brinkman, P. A. Holroyd, J. D. Gardner (eds.), Morphology and Evolution of Turtles 215-250
  • P. C. Sereno and H. C. E. Larsson. 2009. Cretaceous crocodyliformes from the Sahara. ZooKeys 28:1-143
  • P. C. Sereno, A. L. Beck, D. B. Dutheil, B. Gado, H. C. E. Larsson, G. H. Lyon, J. D. Marcot, O. W. M. Rauhut, R. W. Sadleir, C. A. Sidor, D. D. Varricchio, G. P. Wilson, and J. A. Wilson. 1998. A long-snouted predatory dinosaur from Africa and the evolution of spinosaurids. Science 282:1298-1302
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