Elrhaz Formation | |
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Stratigraphic range: Early Cretaceous (Barremian to Albian), | |
Type | Geological formation |
Unit of | Tegama Group |
Underlies | Echkar Formation |
Overlies | Tazolé Formation |
Lithology | |
Primary | Sandstone |
Location | |
Coordinates | 16°48′N9°30′E / 16.8°N 9.5°E |
Approximate paleocoordinates | 3°06′N4°54′E / 3.1°N 4.9°E |
Region | Africa |
Country | Niger |
Extent | Tenere desert |
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 (Tuareg for "the place where camels fear to go") is a site within the Elrhaz Formation (located at 16°50′N9°25′E / 16.833°N 9.417°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]
Chondrichthyes | ||||
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Genus | Species | Material | Notes | Images |
Hybodus [2] | H. sp. | Dorsal spines [2] |
Sarcopterygii | ||||
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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 [7] | A small species. [8] | ||
Neoceratodus [2] | N. africanus [2] | Tooth plates. [9] | Dipnomorph fish. Originally described as Ceratodus africanus, assigned to Neoceratodus by M. Martin, 1982. [10] |
Actinopterygii | ||||
---|---|---|---|---|
Genus | Species | Material | Notes | Images |
Pliodetes [11] | P. nigeriensis [11] | Skull and postcranial material including body scales. [12] | Originally thought to be a semionotid, later assigned to Lepisosteoidei. [12] | |
Pycnodontidae indet. [2] | Indeterminate |
Testudines | ||||
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Genus | Species | Material | Notes | Images |
Francemys [13] | F. gadoufaouaensis [13] | "Shell of a juvenile individual and several articulated and disarticulated plates." [13] | Pelomedusoid turtle. Named in honour of France de Lapparent de Broin. [13] | |
Taquetochelys [14] | T. decorata [14] | A few disarticulated plates and nearly complete skeleton. [15] | Araripemydid turtle, similar in shell size to South American Araripemys (20–30 cm). Laganemys tenerensis was synonimysed with Taquetochelys by Pérez-García, 2018. [15] | |
Teneremys [14] | T. lapparenti [14] | "Several relatively complete skeletons." [13] |
Crocodyliformes | ||||
---|---|---|---|---|
Genus | Species | Material | Notes | Images |
Anatosuchus [16] | A. minor [16] | "Nearly complete skull" | ||
Araripesuchus [16] | A. wegeneri [16] | "Nearly complete skull" | ||
Sarcosuchus [17] | S. imperator | "Partial skeletons, numerous skulls" | ||
Stolokrosuchus | S. lapparenti | |||
Ornithischians | |||||
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Genus | Species | Material | Notes | Images | |
Elrhazosaurus [16] | E. nigeriensis [16] | "Femora." [18] | A dryosaurid | ||
Lurdusaurus [16] | L. arenatus [16] | "Partial skull, fragmentary postcranial skeleton." [19] | |||
Ouranosaurus [16] | O. nigeriensis [16] | "Skull and poscrania, second skeleton." [20] | |||
Theropods | |||||
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Genus | Species | Material | Notes | Images | |
Afromimus | A. tenerensis | "caudal vertebrae, chevrons and portions of the right hind limb" [21] | A Noasaurid | ||
Eocarcharia [16] | E. dinops [22] | "Partial skull and postcranial remains." [23] | Carcharodontosaurid | ||
Kryptops [16] | K. palaios [16] | Postcranial skeleton and partial skull. [24] | Abelisaurid | ||
Suchomimus [16] | S. tenerensis [16] | Partial skull and associated skeleton. [25] | A second, spinosaurid found in the formation, Cristatusaurus , is considered either a separate species or a synonym to Suchomimus [26] |
Sauropods | ||||
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Genus | Species | Material | Notes | Images |
Nigersaurus | N. taqueti | Skull and skeletal remains |
Sarcosuchus is an extinct genus of crocodyliform and distant relative of living crocodilians that lived during the Early Cretaceous, from the late Hauterivian to the early Albian, 133 to 112 million years ago of what is now Africa and South America. The genus name comes from the Greek σάρξ (sarx) meaning flesh and σοῦχος (souchus) meaning crocodile. It was one of the largest pseudosuchians, with the largest specimen of S. imperator reaching approximately 9–9.5 metres (29.5–31.2 ft) long and weighing up to 3.45–4.3 metric tons. It is known from two species; S. imperator from the early Albian Elrhaz Formation of Niger, and S. hartti from the Late Hauterivian of northeastern Brazil. Other material is known from Morocco and Tunisia and possibly Libya and Mali.
Suchomimus is a genus of spinosaurid dinosaur that lived between 125 and 112 million years ago in what is now Niger, West Africa, during the Aptian to early Albian stages of the Early Cretaceous period. It was named and described by paleontologist Paul Sereno and colleagues in 1998, based on a partial skeleton from the Elrhaz Formation. Suchomimus's long and shallow skull, similar to that of a crocodile, earns it its generic name, while the specific name Suchomimus tenerensis alludes to the locality of its first remains, the Ténéré Desert.
Ouranosaurus is a genus of herbivorous basal hadrosauriform dinosaur that lived during the Aptian stage of the Early Cretaceous of modern-day Niger and Cameroon. Ouranosaurus measured about 7–8.3 metres (23–27 ft) long and weighed 2.2 metric tons. Two rather complete fossils were found in the Elrhaz Formation, Gadoufaoua deposits, Agadez, Niger, in 1965 and 1970, with a third indeterminate specimen known from the Koum Formation of Cameroon. The animal was named in 1976 by French paleontologist Philippe Taquet; the type species being Ouranosaurus nigeriensis. The generic name is a combination of ourane, a word with multiple meanings, and sauros, the Greek word for lizard. The specific epithet nigeriensis alludes to Niger, its country of discovery. And so, Ouranosaurus nigeriensis could be interpreted as "brave lizard originating from Niger".
Cristatusaurus is a genus of theropod dinosaur that lived during the Early Cretaceous Period of what is now Niger, 112 million years ago. It was a baryonychine member of the Spinosauridae, a group of large bipedal carnivores with well-built forelimbs and elongated, crocodile-like skulls. The type species Cristatusaurus lapparenti was named in 1998 by scientists Philippe Taquet and Dale Russell, on the basis of jaw bones and some vertebrae. Two claw fossils were also later assigned to Cristatusaurus. The animal's generic name, which means "crested reptile", alludes to a sagittal crest on top of its snout; while the specific name is in honor of the French paleontologist Albert-Félix de Lapparent. Cristatusaurus is known from the Albian to Aptian Elrhaz Formation, where it would have coexisted with sauropod and iguanodontian dinosaurs, other theropods, and various crocodylomorphs.
Lurdusaurus is a genus of massive and unusually shaped iguanodont dinosaur from the Elrhaz Formation in Niger. It contains one species, L. arenatus. The formation dates to the Early Cretaceous, roughly 112 million years ago. Lurdusaurus has a highly atypical body plan for an iguanodont, with a small skull, long neck, rotund torso, and powerful forelimbs and claws, somewhat reminiscent of a ground sloth. Its metacarpals are fused and reinforced into a large block, and the thumb spike is remarkably enormous. These would have allowed the hand to have functioned almost like a ball-and-chain flail. Lurdusaurus is estimated to have been 7–9 m (23–30 ft) long and 2 m high when on all-fours, but its stomach would have been only 70 cm off the ground. It may have weighed 2.5–5.5 t, conspicuously heavy for an iguanodontid this size.
Comahuesuchus is an extinct genus of notosuchian crocodylomorphs from the late Cretaceous of Argentina. It was described by palaeontologist José Bonaparte in 1991. The type species is C. brachybuccalis from the Santonian Bajo de la Carpa Formation. In 2023 another species, C. bonapartei from the Sierra Barrosa Formation and Portezuelo Formation, was assigned to the genus.
Elosuchus is an extinct genus of neosuchian crocodyliform that lived during the Middle Cretaceous of what is now Africa.
Kryptops is a genus of abelisaurid theropod dinosaur from the Early Cretaceous of Niger. It is known from a partial skeleton found at the Gadoufaoua locality in the western Ténéré Desert, in rocks of the Aptian–Albian-age Elrhaz Formation. This dinosaur was described by paleontologists Paul Sereno and Stephen Brusatte in 2008. The genus name means "covered face", in reference to evidence that the face bore a tightly adhering covering. The type species is K. palaios, which means "old".
Asiatoceratodus is an extinct genus of lungfish which lived during the Middle-Late Triassic, Jurassic and Cretaceous periods in what is now Asia (Kyrgyzstan), Africa and South America.
The Echkar Formation is a geological formation comprising sandstones and claystones in the Agadez Region of Niger, central Africa.
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-Late Jurassic (Bathonian-Oxfordian) in age. It is the uppermost unit of the Irhazer Group. Dinosaur remains are among the fossils that have been recovered from the formation.
Nigersaurus is a genus of rebbachisaurid sauropod dinosaur that lived during the middle Cretaceous period, about 115 to 105 million years ago. It was discovered in the Elrhaz Formation in an area called Gadoufaoua, in Niger. Fossils of this dinosaur were first described in 1976, but it was only named Nigersaurus taqueti in 1999, after further and more complete remains were found and described. The genus name means "Niger reptile", and the specific name honours the palaeontologist Philippe Taquet, who discovered the first remains.
Crocodyliformes is a clade of crurotarsan archosaurs, the group often traditionally referred to as "crocodilians". They are the first members of Crocodylomorpha to possess many of the features that define later relatives. They are the only pseudosuchians to survive the K-Pg extinction event.
The In Beceten Formation, also Beceten or Ibecten is a Coniacian to Santonian geologic formation in the Iullemmeden Basin of Niger. Dinosaur remains are among the fossils that have been recovered from the formation, although none have yet been referred to a specific genus. The lithology primarily consists of clays, fine limestones and sandy clays.
Metasuchia is a major clade within the superorder Crocodylomorpha. It is split into two main groups, Ziphosuchia and Neosuchia. Notosuchia is an extinct group that contains primarily small-bodied Cretaceous taxa with heterodont dentition. Neosuchia includes the extant crocodylians and basal taxa, such as peirosaurids and pholidosaurids. It is phylogenetically defined by Sereno et al. (2001) as a clade containing Notosuchus terrestris, Crocodylus niloticus, and all descendants of their common ancestor.
Elrhazosaurus is a genus of basal iguanodontian dinosaur, known from isolated bones found in Early Cretaceous rocks of Niger. These bones were initially thought to belong to a species of the related dryosaurid Valdosaurus, but have since been reclassified.
Araripemydidae is a family of freshwater aquatic turtles belonging to the order Pleurodira, known from the Early Cretaceous of South America and Africa. The family contains two recognised monotypic genera, Araripemys and Taquetochelys, from the Santana Group of Brazil and the Elrhaz Formation of Niger, respectively, which date to the Aptian-Albian stages of the Early Cretaceous. They are consider to be the most basal lineage within the Pelomedusoides. They are thought to have been specialised suction feeders. Laganemys was named in 2013 but was later determined to be synonymous with Taquetochelys.
Afromimus is a genus of theropod dinosaur from the Early Cretaceous Elrhaz Formation of Niger. It contains a single species, A. tenerensis, named in 2017 by Paul Sereno from parts of the right leg, vertebrae, and ribs found in the Ténéré Desert. It was originally classified as an ornithomimosaurian, but subsequently it was argued to be an abelisauroid.
Baryonychinae is an extinct clade or subfamily of spinosaurids from the Early Cretaceous (Valanginian-Albian) of Britain, Portugal, and Niger. In 2023, it consisted of seven genera: Ceratosuchops, Cristatusaurus, Protathlitis, Riparovenator, Suchomimus, Suchosaurus, and Baryonyx, the nominal genus. The clade was named by Charig & Milner in 1986 and defined by Sereno et al. in 1998 and Holtz et al. in 2004 as all taxa more closely related to Baryonyx walkeri than to Spinosaurus aegyptiacus.