Elrhaz Formation

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

Elrhaz Formation
Stratigraphic range: Early Cretaceous (Barremian to Albian),
Outcrops of the formation near Gadoufaoua
TypeGeological formation
Unit ofTegama Group
UnderliesEchkar Formation
OverliesTazolé Formation
Lithology
PrimarySandstone
Location
Coordinates16.8°N 9.5°E / 16.8; 9.5
Approximate paleocoordinates3.1°N 4.9°E / 3.1; 4.9
RegionAfrica
Country Niger
ExtentTenere desert

Its strata date back to the Early Cretaceous, about 125 to 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
Reconstructed skeleton of an anhanguerid from the formation

Gadoufaoua (Tuareg 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.

Dinosaurs of Elrhaz formation

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

Chondrichthyes
Chondrichthyes
GenusSpeciesMaterialNotesImages
Hybodus[2] H. sp. Dorsal spines[2]

Sarcopterygii
Sarcopterygii
GenusSpeciesMaterialNotesImages
Asiatoceratodus[2] A. tiguidiensis[2] Dipnomorph fish. Originally described as Ceratodus tiguidiensis,[3] assigned to Arganodus by M. Martin (1984)[4] and reassigned by Kemp (1998) to the genus Asiatoceratodus.[5]
Mawsonia[6] M. tegamensis[7]
Neoceratodus[2] N. africanus[2] Tooth plates.[8] Dipnomorph fish. Originally described as Ceratodus africanus, assigned to Neoceratodus by M. Martin, 1982.[9]
Neoceratodus forsteri, a modern species

Actinopterygii
Actinopterygii
GenusSpeciesMaterialNotesImages
Pliodetes[10] P. nigeriensis[10] Skull and postcranial material including body scales.[11] Originally thought to be a semionotid, later assigned to Lepisosteoidei.[11]
Pycnodontidae indet.[2] Indeterminate

Testudines
Testudines
GenusSpeciesMaterialNotesImages
Francemys[12] F. gadoufaouaensis[12] "Shell of a juvenile individual and several articulated and disarticulated plates."[12] Pelomedusoid turtle. Named in honour of France de Lapparent de Broin.[12]
Taquetochelys[13] T. decorata[13] A few disarticulated plates and nearly complete skeleton.[14] Araripemydid turtle, similar in shell size to South American Araripemys (20–30 cm). Laganemys tenerensis was synonimysed with Taquetochelys by Pérez-García, 2018.[14]
Teneremys[13] T. lapparenti[13] "Several relatively complete skeletons."[12]

Crocodyliformes
Crocodyliformes
GenusSpeciesMaterialNotesImages
Anatosuchus[15] A. minor[15] "Nearly complete skull"
Araripesuchus[15] A. wegeneri[15] "Nearly complete skull"
Sarcosuchus[16] S. imperator "Partial skeletons, numerous skulls"
Stolokrosuchus S. lapparenti

Ornithischians
Ornithischians
GenusSpeciesMaterialNotesImages
Elrhazosaurus[15] E. nigeriensis[15] "Femora."[17] A dryosaurid
Lurdusaurus[15] L. arenatus[15] "Partial skull, fragmentary postcranial skeleton."[18]
Ouranosaurus[15] O. nigeriensis[15] "Skull and poscrania, second skeleton."[19]

Theropods
Theropods
GenusSpeciesMaterialNotesImages
Afromimus A. tenerensis "caudal vertebrae, chevrons and portions of the right hind limb"[20] A Noasaurid
Eocarcharia[15] E. dinops[21] "Partial skull and postcranial remains."[22] Carcharodontosaurid
Kryptops[15] K. palaios[15] Postcranial skeleton and partial skull.[23] Abelisaurid
Suchomimus[15] S. tenerensis[15] Partial skull and associated skeleton.[24] A second, spinosaurid found in the formation, Cristatusaurus, is considered either a separate species or a synonym to Suchomimus[25]

Sauropods
Sauropods
GenusSpeciesMaterialNotesImages
Nigersaurus N. taqueti Skull and skeletal remains

See also

References
  1. SCIENCE IN THE NEWS - Nov. 13: Digest - 12 November 2001 Voice of America
  2. "On the dinosaurian and crocodilian locality of Gadoufaoua (Republic of Niger)" (PDF). From Mr. Philippe Taquet (1970), presented by Mr. Jean Piveteau.
  3. N. Tabaste. 1963. Étude derestes de poissons du Crétacé saharien [Study of fish remains from the Saharan Cretaceous]. Mélanges Ichthyologiques Dédiés à la Mémoire d’Achille Valenciennes (1794–1865). Mémoires de l’Institute Français d’Afrique Noire 68:437-485
  4. Martin, M., 1984. Révision des Arganodontidés et des Néocératodontidés (Dipnoi, Ceratodontiformes) du Crétacé africain. Neues Jb. Geol. Paläontol. Abh. 169, 225–260.
  5. Kemp, A. 1998. Skull structure in post-paleozoic lungfish. Journal of Vertebrate Paleontology, 18(1): 43-63.
  6. "Fossilworks: Gateway to the Paleobiology Database". www.fossilworks.org. Retrieved 2022-05-16.
  7. "Fossilworks: Gateway to the Paleobiology Database". www.fossilworks.org. Retrieved 2022-05-16.
  8. Federico Fanti, Gabriele Larocca Conte, Luana Angelicola, Andrea Cau, 2016. "Why so many dipnoans? A multidisciplinary approach on the Lower Cretaceous lungfish record from Tunisia." Palaeogeography, Palaeoclimatology, Palaeoecology. 449: 255-265. DOI:10.1016/j.palaeo.2016.02.024
  9. M. Martin. 1982. Nouvelles données sur la phylogénie et la systématique des dipneustes postpaléozoïques [New data on the phylogeny and systematics of post-Paleozoic dipnoans]. Comptes Rendues de l'Academie des Sciences, Paris, Série II 294:611-614
  10. S. Wenz. 1999. Pliodetes nigeriensis, gen. nov. et. sp. nov., a new semionotid fish from the Lower Cretaceous of Gadoufaoua (Niger Republic): phylogenetic comments. In G. Arratia & H.-P. Schultz (ed.), Mesozoic Fishes 2—Systematics and Fossil Record 107-120
  11. A. López-Arbarello. 2012. Phylogenetic interrelationships of ginglymodian fishes (Actinopterygii: Neopterygii). PLoS ONE
  12. Pérez-García, Adán (1 October 2019). "The African Aptian Francemys gadoufaouaensis gen. et sp. nov.: New data on the early diversification of Pelomedusoides (Testudines, Pleurodira) in northern Gondwana". Cretaceous Research. 102: 112–126. doi:10.1016/j.cretres.2019.06.003. ISSN 0195-6671.
  13. F. de Broin. 1980. Les tortues de Gadoufaoua (Aptien du Niger); aperçu sur la Paléobiogéographie des Pelomedusidae (Pleurodira). Mémoires de la Société Géologique de France
  14. Pérez-García, Adán (2018). "Identification of the Lower Cretaceous pleurodiran turtle Taquetochelys decorata as the only African araripemydid species". Comptes Rendus Palevol. 18: 24–32. doi:10.1016/j.crpv.2018.04.004. ISSN 1631-0683.
  15. "68.1 Departement D'Agedez, Niger; 1. Elrhaz Formation," in Weishampel, et al. (2004). Page 572
  16. Sereno et al., 2011
  17. "Table 19.1," in Weishampel, et al. (2004). Page 415.
  18. "Table 19.1," in Weishampel, et al. (2004). Page 416.
  19. "Table 19.1," in Weishampel, et al. (2004). Page 417.
  20. Sereno, P. (2017). "Early Cretaceous ornithomimosaurs (Dinosauria: Coelurosauria) from Africa". Ameghiniana. 54 (5): 576–616. doi:10.5710/AMGH.23.10.2017.3155.
  21. Sereno & Brusatte, 2008
  22. "Table 4.1," in Weishampel, et al. (2004). Page 73.
  23. "Table 4.1," in Weishampel, et al. (2008). Page 72.
  24. "Table 4.1," in Weishampel, et al. (2004). Page 72.
  25. Rauhut, O.W.M. (2003). "The interrelationships and evolution of basal theropod dinosaurs". Special Papers in Palaeontology 69: 1-213.

Bibliography

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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