Evidence of the existence of specialised ancient marsupials have been found in Australia. They had teeth that were "hammer-like" for crushing snail shells. Lizards living today in rain forests have similar teeth. They had premolars like the teeth in humans located between the molars and canines. Researchers could not determine at first what the strange teeth were used for. It was the first time that such teeth had been found in marsupials. Like the Tasmanian tiger a marsupial which filled the role of native dog in Australia, so this marsupial more than 10 million years ago, lived in the niche that the pink-tongued skink holds today. This wet rain forest lizard is quite large, about 40 cm in length, so it's ancestor would have been a tough competitor. The extinct marsupial became extinct when the weather changed in Australia and inland rain forests receded toward the coast. Lizards could survive in the new environment. The marsupial could not. Riversleigh in norther...