Elrhazosaurus

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Elrhazosaurus
Temporal range: Early Cretaceous, ~115  Ma
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Valdosaurus nigeriensis.JPG
Femur of Elrhazosaurus nigeriensis.
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Clade: Ornithischia
Clade: Ornithopoda
Family: Dryosauridae
Genus: Elrhazosaurus
Galton, 2009
Species:
E. nigeriensis
Binomial name
Elrhazosaurus nigeriensis
Galton, 2009 (Galton and Taquet, 1982)
Synonyms

Elrhazosaurus (meaning "Elrhaz lizard") 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.

Contents

Discovery and history

Elrhazosaurus is based on MNHN  GDF 332, a left thigh bone collected by Philippe Taquet from the upper part of the Elrhaz Formation of Gadoufaoua in the Ténéré Desert, Agadez, Niger. This rock unit dates to the late Aptian stage, approximately 115 million years ago. The bone was designated as the type specimen of a new species of Valdosaurus (V. nigeriensis) by Peter Galton and Taquet in 1982. It was differentiated from the type species V. canaliculatus by the locations of trochanters and other details. Because V. canaliculatus is known from Europe, the presence of a related species in central Africa was interpreted as evidence for a land connection between the two continents. [1]

V. nigeriensis was given its own genus, Elrhazosaurus, by Galton in 2009. This was done on the grounds of differing morphology and geologic age versus V. canaliculatus. He retained it as a dryosaurid. [2] While Elrhazosaurus is sometimes described as only known from thigh bones, [3] at least one upper arm bone has been assigned to the genus. [2]

Paleoecology and paleobiology

Life restoration of E. nigeriensis Elrhazosaurus NT.png
Life restoration of E. nigeriensis

The Elrhaz Formation is mostly made up of fluvial sandstones. A diverse assemblage of fossil animals has been recovered, including freshwater bivalves, hybodont sharks, bony fish, turtles, several genera of crocodylomorphs ( Anatosuchus , Araripesuchus , Sarcosuchus , and Stolokrosuchus ), undescribed ornithocheirid pterosaurs, the theropod dinosaurs Eocarcharia , Kryptops , Suchomimus , and an undescribed noasaurid (possibly Bahariasaurus ), the sauropods Nigersaurus and an undescribed titanosaurian (possibly Malawisaurus ), and the iguanodontians Lurdusaurus and Ouranosaurus . [4] As a dryosaurid iguanodontian, Elrhazosaurus would have been a lightly built herbivorous bipedal runner. [3]

Related Research Articles

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<i>Sarcosuchus</i> Extinct genus of reptiles

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.

<i>Suchomimus</i> Extinct genus of dinosaurs

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.

<i>Valdosaurus</i> Extinct genus of dinosaurs

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<i>Ouranosaurus</i> Extinct genus of dinosaurs

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".

<i>Camptosaurus</i> Extinct genus of dinosaurs

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<i>Cristatusaurus</i> Extinct genus of dinosaurs

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.

<i>Kangnasaurus</i> Extinct genus of dinosaurs

Kangnasaurus is a genus of iguanodontian ornithopod dinosaur found in supposedly Early Cretaceous rocks of South Africa. It is known from a tooth and possibly some postcranial remains found in the early-Aptian Kalahari Deposits Formation. It was probably similar to Dryosaurus.

<i>Lurdusaurus</i> Extinct genus of dinosaurs

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.

<i>Nanosaurus</i> Extinct genus of dinosaurs

Nanosaurus is the name given to a genus of neornithischian dinosaur that lived about 155 to 148 million years ago, during the Late Jurassic-age. Its fossils are known from the Morrison Formation of the south-western United States. The type and only species, Nanosaurus agilis, was described and named by Othniel Charles Marsh in 1877. The taxon has a complicated taxonomic history, largely the work of Marsh and Peter M. Galton, involving the genera Laosaurus, Hallopus, Drinker, Othnielia, and Othnielosaurus, the latter three now being considered to be synonyms of Nanosaurus. It had historically been classified as a hypsilophodont or fabrosaur, types of generalized small bipedal herbivore, but more recent research has abandoned these groupings as paraphyletic and Nanosaurus is today considered a basal member of Neornithischia.

<span class="mw-page-title-main">Dryosauridae</span> Extinct family of dinosaurs

Dryosauridae was a family of primitive iguanodonts, first proposed by Milner & Norman in 1984. They are known from Middle Jurassic to Early Cretaceous rocks of Africa, Europe, and North America.

<i>Kryptops</i> Extinct genus of dinosaurs

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".

<i>Eocarcharia</i> Extinct genus of reptiles

Eocarcharia is a genus of carcharodontosaurid theropod dinosaur from the Early Cretaceous Elrhaz Formation that lived in the Sahara 112 million years ago, in what today is the country of Niger. It was discovered in 2000 on an expedition led by University of Chicago paleontologist Paul Sereno. The type and only species is Eocarcharia dinops. Its teeth were shaped like blades and were used for disabling live prey and ripping apart body parts. Eocarcharia’s brow is swollen into a massive band of bone, giving it a menacing glare. It may have reached lengths of 6–8 m (19.7–26.2 ft).

<i>Nigersaurus</i> Genus of reptiles (fossil)

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.

<span class="mw-page-title-main">Elrhaz Formation</span>

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

<i>Owenodon</i> Extinct genus of dinosaurs

Owenodon is a genus of iguanodontian dinosaur known from a partial lower jaw discovered in Early Cretaceous-age rocks of Durlston Bay, Dorset, United Kingdom, and possibly also Romania and Spain. The specimen, NHM R2998, comes from the Purbeck Limestone, dating to the middle Berriasian stage. It was first described by Richard Owen, who in 1874 assigned it to Iguanodon as the type specimen of the new species I. hoggii, the specific name honouring naturalist A.J. Hogg who had originally collected the fossil in 1860. The bone was damaged during initial preparation but was freed from the surrounding rock matrix by an acid bath between 1975 and 1977. David Norman and Paul Barrett subsequently transferred the species to Camptosaurus in 2002, but this was challenged, and in 2009 Peter Galton assigned the species to the new genus Owenodon, meaning "Owen's tooth", named after Sir Richard Owen. Galton interpreted the genus as an iguanodontoid more derived than Camptosaurus but less derived than Lurdusaurus.

References

  1. Galton, Peter M.; Taquet, Philippe (1982). "Valdosaurus, a hypsilophodontid dinosaur from the Lower Cretaceous of Europe and Africa". Géobios. 15 (2): 147–159. doi:10.1016/s0016-6995(82)80017-x.
  2. 1 2 Galton, Peter M. (2009). "Notes on Neocomian (Late Cretaceous) ornithopod dinosaurs from England – Hypsilophodon, Valdosaurus, "Camptosaurus", "Iguanodon" – and referred specimens from Romania and elsewhere" (PDF). Revue de Paléobiologie. 28 (1): 211–273.
  3. 1 2 Norman, David B. (2004). "Basal Iguanodontia". In Weishampel, D.B.; Dodson, P.; Osmólska H. (eds.). The Dinosauria (2nd ed.). Berkeley: University of California Press. pp. 413–437. ISBN   0-520-24209-2.
  4. Sereno, Paul C.; Brusatte, Stephen L. (2008). "Basal abelisaurid and carcharodontosaurid theropods from the Lower Cretaceous Elrhaz Formation of Niger" (PDF). Acta Palaeontologica Polonica. 53 (1): 15–46. doi: 10.4202/app.2008.0102 .