Imperobator
"powerful warrior"
- Lived
- 72 to 66 million years ago, Late Cretaceous
- Diet
- Carnivore
- Group
- Theropods, Dromaeosauridae
- Found in
- Antarctica
- Named by
- Ely and Case 2019
Where its fossils were found
The evidence
Today
70 million years ago
Habitat
It lived in a forested Antarctica that was much warmer than today. Other dinosaurs from the region include Antarctopelta, Morrosaurus and Trinisaura.
Field notes
About Imperobator
What it was like
Imperobator was a feathered, two-legged hunter related to the raptors. It is known only from parts of the legs and feet, so its full size and shape are uncertain. It was first thought to be very large, but later studies suggest a more modest animal.
Its world
It lived about 72 to 66 million years ago, at the end of the Late Cretaceous, in Antarctica. The land there was forested then, and much warmer than today. Its bones come from the Snow Hill Island Formation, and other dinosaurs from the region include the armored Antarctopelta and the plant eaters Morrosaurus and Trinisaura.
How it was found
Ely and Case named Imperobator in 2019 from one find. It is one of very few meat-eating dinosaurs known from Antarctica.
Field gallery
More views of Imperobator
Scenes reconstructed from the available fossil evidence.
1 of 2
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 Imperobator.
The evidence
The science behind Imperobator
Which parts of the picture come from its own bones, and which come from its relatives.
From its own fossils
- The original find preserves weathered parts of both hind legs, ankles, foot bones and toes.
- A narrow middle foot bone supports comparisons with southern relatives such as Buitreraptor.
Borrowed from relatives
- The missing head, arms, torso and tail are restored by comparison with Buitreraptor.
- A feather covering is inferred from feathered relatives such as Anchiornis.
Still unknown
- Its full size and body proportions.
- The shape and size of the claw on its second toe.
- Its closest relatives and feather colors.
Discovery timeline
- 2015Close relativeLindgren et al.
- 2019Named itEly & Case
- 2025RedescriptionMotta et al.
Key papers
The research behind what we know of Imperobator
Close relative
Studied preserved feathers in Anchiornis, providing a comparison for the feather covering inferred in Imperobator.
Molecular composition and ultrastructure of Jurassic paravian feathers. Scientific Reports 5
Read the paper : Molecular composition and ultrastructure of Jurassic paravian feathers (opens in a new tab)Named it
Named Imperobator from Antarctic leg and foot bones, identifying a birdlike predator with an unusual combination of foot features.
Phylogeny of a new gigantic paravian (Theropoda; Coelurosauria; Maniraptora) from the Upper Cretaceous of James Ross Island, Antarctica. Cretaceous Research 101: 1-16
Read the paper : Phylogeny of a new gigantic paravian (Theropoda; Coelurosauria; Maniraptora) from the Upper Cretaceous of James Ross Island, Antarctica (opens in a new tab)Redescription
Reinterpreted several foot bones and placed Imperobator among southern birdlike predators related to Buitreraptor.
Unenlagiid Affinities for Imperobator antarcticus (Paraves: Theropoda): Paleobiogeographical Implications. Ameghiniana 62: 69-79
Read the paper : Unenlagiid Affinities for Imperobator antarcticus (Paraves: Theropoda): Paleobiogeographical Implications (opens in a new tab)
Close relatives
Other members of Dromaeosauridae
Sources: Wikidata