Imperobator ("powerful warrior") is a genus of probable unenlagiid paravian theropod dinosaurs, that lived during the Maastrichtian age of the Late Cretaceous in what is now James Ross Island in Antarctica.

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.

These belong to the Cape Lamb Member of the Snow Hill Island Formation, which dates to the early Maastrictian age of the Late Cretaceous (~71 mya).

However, additional fossils were located in the facilities of Eastern Washington University and the South Dakota School of Mines and Technology that pertain to UCMP 276000 including skull fragments which may be from the premaxilla, maxilla, and/or dentary as well as a caudal vertebra, more teeth, and pedal elements.

[4] The third Antarctic Peninsula Paleontology Project expedition in 2011 and 2016 to the same locality found even more fossils from the UCMP 276000 individual, such as a tooth, incomplete pedal ungual, cranial fragments, and indeterminate bone shards, now in the collections of the American Museum of Natural History under number AMNH FARB 30894.

[4] The fossils were first reported in published literature in 2005, with the authors theorizing that the specimen was of a "primitive holdover of the original Gondwanan dinosaur assemblage", noting its less derived characteristics compared to other Maastrichtian dromaeosaurs.

[2][1] The specimen was formally described as the holotype of a new genus and species, Imperobator antarcticus, by American paleontologists Ricardo Ely and Judd Case in 2019.

The distal portion of the left tibia (shin bone) and some of the astragalus are preserved, though much of their characteristic features are missing due to erosion and frost.

[2][10] Before Imperobator was officially described, a paper published in 2007 announced the specimen and assigned it to the clade Dromaeosauridae; it was nicknamed the "Naze dromaeosaur".

[15][16] From the site in which Imperobator was found, pollen grains from Asteraceae, the group containing sunflowers and daisies, are the oldest records of the family that were collected.

[18] The Cape Lamb Member of the formation has yielded several other fossil remains, such as the herbivorous ornithopod Morrosaurus, an indeterminate hypsilophodontid ornithopod,[14] the avian Antarcticavis,[19] an indeterminate neornithine,[20] an unnamed pterosaur,[21] the elasmosaurid Vegasaurus;[22] the mosasaurs Taniwhasaurus,[23] Liodon,[24] Plioplatecarpus,[23] and Mosasaurus,[24] sharks such as Notidanodon,[14] and several bony fishes from the groups Teleostei,[14] Actinopterygii,[25] Ichthyodectiformes,[14] and Sphenocephalidae.