Elrhazosaurus
"Elrhaz lizard"
- Lived
- 121 to 113 million years ago, Early Cretaceous
- Diet
- Herbivore
- Group
- Ornithopods, Dryosauridae
- Found in
- Niger
- Named by
- Galton 2009
Where its fossils were found
The evidence
Today
115 million years ago
Habitat
It lived in the river landscape recorded by the Elrhaz Formation in Niger. Ouranosaurus, Nigersaurus and Suchomimus are known from the same rocks.
Field notes
About Elrhazosaurus
What it was like
Elrhazosaurus was a small, two-legged plant eater from the dryosaur family, relatives of Dryosaurus. It is known from a few bones, including a thigh bone.
Its world
It lived in the Early Cretaceous in what is now Niger. Its bones come from the Elrhaz Formation, a land of rivers shared with the sail-backed Ouranosaurus, the long-necked Nigersaurus and the fish-eating Suchomimus.
How it was found
Its bones were first described as a species of Valdosaurus. Galton gave it its own genus in 2009.
Field gallery
More views of Elrhazosaurus
Scenes reconstructed from the available fossil evidence.
Lived alongside
Found in the same rock formations
A rock formation can hold fossils laid down millions of years apart, so not every animal here met Elrhazosaurus.
The evidence
The science behind Elrhazosaurus
Which parts of the picture come from its own bones, and which come from its relatives.
From its own fossils
- The genus is based on an isolated thigh bone.
- The thigh bone has a pit on its inner side and a deep, slanting groove at the knee end.
- The upper end of another thigh bone was referred to Elrhazosaurus.
Borrowed from relatives
- Its missing head and body are reconstructed from general dryosaurid anatomy.
Still unknown
- The shape of its skull.
- Its skin texture and color.
- Experts disagree over whether its thigh-bone features distinguish a valid species: one reassessment judged them too widely shared among early plant-eating dinosaurs.
Discovery timeline
- 1982Full descriptionGalton & Taquet
- 2009Named itGalton
- 2022Family treePoole
Key papers
The research behind what we know of Elrhazosaurus
Full description
First described the species from Niger as a member of Valdosaurus and compared it with fossils from England.
Valdosaurus, a hypsilophodontid dinosaur from the Lower Cretaceous of Europe and Africa. Geobios 15: 147-159
Read the paper : Valdosaurus, a hypsilophodontid dinosaur from the Lower Cretaceous of Europe and Africa (opens in a new tab)Named it
Separated the dinosaur from Valdosaurus using the shape of its thigh bone and the different ages of the rocks.
Notes on Neocomian (Lower Cretaceous) ornithopod dinosaurs from England - Hypsilophodon, Valdosaurus, "Camptosaurus", "Iguanodon" - and referred specimens from Romania and elsewhere. Revue de Paléobiologie, Genève 28: 211-273
No link available
Family tree
Questioned whether the thigh bone has distinctive enough features to identify Elrhazosaurus as a valid species.
Phylogeny of iguanodontian dinosaurs and the evolution of quadrupedality. Palaeontologia Electronica
Read the paper : Phylogeny of iguanodontian dinosaurs and the evolution of quadrupedality (opens in a new tab)
Close relatives
Other members of Dryosauridae
Sources: Wikidata