Rapator was a large meat-eater—maybe—from Australia. It was a theropod dinosaur that lived during the early Cretaceous period, from 113 -97.5 million years ago. To date, only one hand bone has been found but it is enough for scientists to determine the basic type of dinosaur from which the bone came. This is a good example of how a little clue can provide a lot of information. Rapator was probably about as large as Allosaurus, but it isn't known if they were related.Australia is not known for its dinosaur discoveries, so Rapator represents a rare and interesting bit of prehistory. It has been suggested that Rapator was a large ornitholestid, a carnosaur, or even a very large bird-like dinosaur. Some have envisioned this creature as feathered and belonging to the alvarezsauria. A single opalised hand bone was described and named by Friederich von Huene in 1932.

It so closely resembled that of the coelurosaur Ornitholestes hermani from North America that it was given the species name ornitholestoides, meaning 'like Ornitholestes'. Rapator was named by von Huene in 1932. The name is probably derived from the Latin word 'raptor', which means 'that which seizes', or for a more modern short-hand translation, 'thief' or 'plunderer'.

Rapator may have been up to 9 metres in length, depending on its exact body shape. Other theropod bone fragments from Lightning Ridge, NSW, could also belong with Rapator. The exact relationships of Rapator are unclear, although it appears to be completely different from other families known at this time, such as the Allosaurids or Carcharodontosaurids. It has been suggested that Rapator could have belonged to the Abelisaurs, although this seems to have been based on biogeographic grounds alone.

More recent examination of the bone has led to the idea that it may actually be phalanx 1 of manual digit I of a large alvarezsaur, a group of extremely bird-like theropods known from South America and Mongolia. If so, then this would bring its overall length down to about 6 metres.

Rapator is characterised by its first metacarpal bone having an elongated posteromedial process, a feature otherwise seen only in Ornitholestes. It differs from that genus, however, in that the first metacarpal bone in Rapator is considerably larger, broader relative to length, more robust, and with the posteromedial process more prominently developed.