Some scientists regard with skepticism the contention that "Megalania" was the only, or even principal, predator of the Australian Pleistocene megafauna. They note that the "marsupial lion" ("Thylacoleo carnifex") has been implicated with the butchery of very large Pleistocene mammals, while "Megalania" has not. In addition, they note that "Megalania" fossils are extremely uncommon, in contrast to "T. carnifex" with its wide distribution across Australian Pleistocene deposits. "Quinkana", a genus of terrestrial crocodiles that grew up to 6 m and was present until around 40,000 years ago, has also been marked as another apex predator of Australian megafauna.