Arkansaurus
"Arkansas lizard"
Type species Arkansaurus fridayi
- Lived
- 113 to 101 million years ago, Early Cretaceous
- Diet
- Omnivore
- Group
- Theropods
- Found in
- United States
- Named by
- Hunt and Quinn 2018
Where its fossils were found
The evidence
Today
105 million years ago
Habitat
Streams crossed a low coastal landscape in what is now Arkansas. Other dinosaurs from the region's Early Cretaceous rocks include Acrocanthosaurus and Deinonychus.
Field notes
About Arkansaurus
What it was like
Arkansaurus was an ornithomimosaur, one of the lightly built, long-legged theropods related to the ostrich-like dinosaurs. It is known only from a foot, so its size and look are uncertain.
Its world
It lived in the Early Cretaceous, in what is now Arkansas.
How it was found
Hunt and Quinn named Arkansaurus in 2018, decades after the foot bones were found. The type species is Arkansaurus fridayi. It is the first dinosaur known from Arkansas and is the state dinosaur.
Field gallery
More views of Arkansaurus
Scenes reconstructed from the available fossil evidence.
1 of 3
The evidence
The science behind Arkansaurus
Which parts of the picture come from its own bones, and which come from its relatives.
From its own fossils
- A nearly complete right foot, with long bones leading to the toes.
- The toe claws differ in shape, helping distinguish it from other ostrich-like dinosaurs.
Borrowed from relatives
- Shenzhousaurus provides a comparison for the missing head, trunk and hips.
- Pelecanimimus helps restore the long neck and arms.
- It may have worn a coat of feathers like those preserved in Ornithomimus.
Still unknown
- Its full size and body proportions.
- Whether its jaws carried teeth.
- Its color and the extent of any feather covering.
Discovery timeline
- 2012Close relativeZelenitsky et al.
- 2018Named itHunt & Quinn
- 2018Close relativeMcFeeters, Ryan & Cullen
Key papers
The research behind what we know of Arkansaurus
Close relative
Found feathers in Ornithomimus, providing a comparison for the possible covering of Arkansaurus.
Feathered Non-Avian Dinosaurs from North America Provide Insight into Wing Origins. Science 338: 510-514
Read the paper : Feathered Non-Avian Dinosaurs from North America Provide Insight into Wing Origins (opens in a new tab)Named it
Named Arkansaurus from a nearly complete foot and identified it as an early member of the ostrich-like dinosaurs.
A new ornithomimosaur from the Lower Cretaceous Trinity Group of Arkansas. Journal of Vertebrate Paleontology 38: e1421209
Read the paper : A new ornithomimosaur from the Lower Cretaceous Trinity Group of Arkansas (opens in a new tab)Close relative
Showed that toe-claw shape varies within a foot, a useful caution when comparing the differently shaped claws of Arkansaurus.
Positional Variation in Pedal Ungulas of North American Ornithomimids (Dinosauria, Theropoda): A Response to Brownstein (2017). Vertebrate Anatomy Morphology Palaeontology 5
Read the paper : Positional Variation in Pedal Ungulas of North American Ornithomimids (Dinosauria, Theropoda): A Response to Brownstein (2017) (opens in a new tab)
Close relatives
Other members of Ornithomimosauria
Sources: Wikidata