Elrhaz Formation

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°48′N 9°30′E / 16.8°N 9.5°E / 16.8; 9.5
Approximate paleocoordinates3°06′N 4°54′E / 3.1°N 4.9°E / 3.1; 4.9
RegionAfrica
CountryNiger
ExtentTenere desert
Elrhaz Formation (Niger)

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

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

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 / 16.833°N 9.417°E / 16.833; 9.417) 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. Based on the sedimentary and fossil record, Gadoufaoua had trees, plants, and wide rivers 112 million years ago. 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
Genus Species Material Notes Images
Hybodus[2] H. sp. Dorsal spines[2]

Sarcopterygii

Sarcopterygii
Genus Species Material Notes Images
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[6] A small species.[7]
Neoceratodus[2] N. africanus[2] Tooth plates.[8] Dipnomorph fish. Originally described as Ceratodus africanus, assigned to Neoceratodus by M. Martin, 1982.[9]

Actinopterygii

Actinopterygii
Genus Species Material Notes Images
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
Genus Species Material Notes Images
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 synonymysed with Taquetochelys by Pérez-García, 2018.[14]
Teneremys[13] T. lapparenti[13] "Several relatively complete skeletons."[12]

Crocodyliformes

Crocodyliformes
Genus Species Material Notes Images
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

Dinosaurs

Ornithischians

Ornithischians
Genus Species Material Notes Images
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
Genus Species Material Notes Images
Afromimus A. tenerensis "caudal vertebrae, chevrons and portions of the right hind limb"[20] A putative noasaurid[21]
Cristatusaurus[22] C. lapparenti[22] Jaw bones and vertebral fragments.[22] A spinosaurid potentially synonymous with Suchomimus[23]
Eocarcharia[15] E. dinops[24] "Partial skull and postcranial remains."[25] Known from chimaeric remains; the holotype and skull roof material likely derive from a baryonychine spinosaurid, while the referred maxilla is from a carcharodontosaurid.[26]
Kryptops[15] K. palaios[15] Postcranial skeleton and partial skull.[27] An abelisaurid
Suchomimus[15] S. tenerensis[15] Partial skull and associated skeleton.[28] A baryonychine spinosaurid

Sauropods

Sauropods
Genus Species Material Notes Images
Nigersaurus N. taqueti Skull and skeletal remains A rebbachisaurid.

Flora

Plants
Genus Species Material Notes Images
Paradoxopteris[29] P. stromeri A tree fern and member of Matoniaceae.
Protophyllocladoxylon P.chudeaui A conifer[29]

See also

References

  1. ^ SCIENCE IN THE NEWS - Nov. 13: Digest - 12 November 2001 Voice of America
  2. ^ a b c d e f g "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. ^ a b "Fossilworks: Gateway to the Paleobiology Database". Paleobiology Database. Retrieved 2022-05-16.
  7. ^ Taquet, Philippe (1998). Dinosaur impressions : postcards from a paleontologist. Internet Archive. Cambridge; New York : Cambridge University Press. ISBN 978-0-521-58372-5.
  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 Rendus de l'Académie des Sciences, Paris, Série II 294:611-614
  10. ^ a b 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 b A. López-Arbarello. 2012. Phylogenetic interrelationships of ginglymodian fishes (Actinopterygii: Neopterygii). PLoS ONE
  12. ^ a b c d e 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. Bibcode:2019CrRes.102..112P. doi:10.1016/j.cretres.2019.06.003. ISSN 0195-6671.
  13. ^ a b c d 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. ^ a b 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. ^ a b c d e f g h i j k l m n o "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. ^ Cerroni, M.A.; Agnolin, F.L.; Brissón Egli, F.; Novas, F.E. (2019). "The phylogenetic position of Afromimus tenerensis Sereno, 2017 and its paleobiogeographical implications". Journal of African Earth Sciences. 159: 103572. Bibcode:2019JAfES.15903572C. doi:10.1016/j.jafrearsci.2019.103572. S2CID 201352476.
  22. ^ a b c Taquet, Philippe; Russell, Dale A (1998). "New data on spinosaurid dinosaurs from the early cretaceous of the Sahara". Comptes Rendus de l'Académie des Sciences, Série IIA. 327 (5): 347–353. Bibcode:1998CRASE.327..347T. doi:10.1016/S1251-8050(98)80054-2. ISSN 1251-8050.
  23. ^ Rauhut, O.W.M. (2003). "The interrelationships and evolution of basal theropod dinosaurs". Special Papers in Palaeontology 69: 1-213.
  24. ^ Sereno & Brusatte, 2008
  25. ^ "Table 4.1," in Weishampel, et al. (2004). Page 73.
  26. ^ Cau, Andrea; Paterna, Alessandro (May 2025). "Beyond the Stromer's Riddle: the impact of lumping and splitting hypotheses on the systematics of the giant predatory dinosaurs from northern Africa". Italian Journal of Geosciences. 144 (2): 1–24. doi:10.3301/IJG.2025.10.
  27. ^ "Table 4.1," in Weishampel, et al. (2008). Page 72.
  28. ^ "Table 4.1," in Weishampel, et al. (2004). Page 72.
  29. ^ a b "Niveau des Innocents, Gadoufaoua (Cretaceous of Niger)". paleobiodb.org. Retrieved 2025-05-29.

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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