Antarctica wasn't always a frozen wasteland -- 250 million years ago, it was covered in forests and rivers and the temperature rarely dipped below freezing. It was also home to diverse wildlife, including early relatives of the dinosaurs. Scientists have just discovered the newest member of that family -- an iguana-sized reptile. The fossil skeleton is incomplete, but paleontologists still have a good feel for the animal, named Antarctanax shackletoni (the former means "Antarctic king," the latter is a nod to polar explorer Ernest Shackleton). Based on its similarities to other fossil animals, the researchers surmise that Antarctanax was a carnivore that hunted bugs, early mammal relatives and amphibians. About 2 million years before Antarctanax lived -- the blink of an eye in geologic time -- Earth underwent its largest mass extinction ever. Climate change, caused by volcanic eruptions, killed 90 percent of all animal life. The fact that scientists have found Antarctanax helps bolster the idea that Antarctica was a place of rapid evolution and diversification after the mass extinction.