| Imperobator Temporal range: Late Cretaceous (Maastrichtian)
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|---|---|
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| Left hind limb and full body reconstruction | |
Scientific classification 
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| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Clade: | Dinosauria |
| Clade: | Saurischia |
| Clade: | Theropoda |
| Clade: | Paraves |
| Genus: | โ Imperobator Ely & Case, 2019 |
| Species: | †I. antarcticus
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| Binomial name | |
| †Imperobator antarcticus Ely & Case, 2019
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Imperobator ("powerful warrior") is a genus of paravian theropod, a group of large, three-toed carnivorous dinosaurs, that lived during the Maastrichtian age of the Late Cretaceous period in what is now James Ross Island in Antarctica. Imperobator is one of only two non-avian theropods known from Antarctica, crossing over to the landmass when it was part of Gondwana. The only described specimen was found in 2003 by an expedition launched by the University of California Museum of Paleontology and initially described as a dromaeosaur in 2007. However, later searches reported more fossils from the site including teeth and skull bones. The fossils were formally described as a new genus of giant paravian in 2019.
Imperobator is one of the largest known paravians, with an estimated height of 2 metres (6 ft 7 in), making it of comparable size to the gigantic dromaeosaurs such as Utahraptor. Because its fossils lack the characteristic "sickle claw" of dromaeosaurs on the second digit, Imperobator is provisionally classified as a basal paravian of uncertain affinities.
It was discovered in the Cape Lamb Member strata of the Snow Hill Island Formation, which bears a variety of other fossils, many of them unique as they evolved in the isolation of Antarctica after the breakup of Gondwana. Imperobator coexisted with the ornithopod dinosaur Morrosaurus and bird Antarcticavis in addition to a menagerie of mosasaurs, plesiosaurs, and a pterosaur.