Almost every tyrannosaur ever discovered, from the feather-covered Dilong to the gargantuan
As reported by paleontologists Roger Benson, Paul Barrett, Tom Rich and Pat Vickers-Rich, a partial hip found at the appropriately-named Dinosaur Cove site in southern Australia appears to have belonged to an approximately 100 million year old tyrannosauroid dinosaur. Even though it is not much to go on, and the authors refrain from naming the dinosaur in their brief report, the specimen shows several traits that are seen only among tyrant dinosaurs (including a rough, or "rugose," patch near the top). It is entirely possible that the bone could represent some hitherto unknown type of dinosaur, but based upon what paleontologists have discovered so far the simplest explanation is that the bones denote the presence of a southern-hemisphere tyrannosaur.
What is particularly interesting, though, is that 100 million years ago Dinosaur Cove was very close to the South Pole. Whatever this dinosaur was, it was living in a place that was probably cooler (at least seasonally) than places inhabited by other dinosaurs at the time. Many dinosaurs, including tyrannosaurs, have been discovered in Arctic deposits, and if further discoveries help us to understand this new southern dinosaur we may learn more about the lives of Antarctic dinosaurs, too.
For more on this discovery, see Darren Naish's Tetrapod Zoology and a post from Roger Benson on Dave Hone's Archosaur Musings.
Benson, R., Barrett, P., Rich, T., & Vickers-Rich, P. (2010). A Southern Tyrant Reptile Science, 327 (5973), 1613-1613 DOI: 10.1126/science.1187456