Mammals of Australia introductions of placental mammals into Australian fauna were about (rats), several thousand years ago (dingo), and 200 years ago (many species); the last two were made by humans. Some claims were made about placental mammal fossils from the Eocene of Australia, called "Tingamarra". These claims are based on only one found tooth having some characteristic features of condylarth, and were discussed widely. But both the age and placental nature of these fossils were challenged by other researchers. Monotremes are mammals with a unique method of reproduction: they lay eggs instead of giving birth to live young. Two of the five
Australia (continent) to the Australian mainland. As the continent drifted north from Antarctica, a unique fauna, flora and mycobiota developed. Marsupials and monotremes also existed on other continents, but only in Australia–New Guinea did they out-compete the placental mammals and come to dominate. New Guinea has 284 species and six orders of mammals: monotremes, three orders of marsupials, rodents and bats; 195 of the mammal species (69%) are endemic. New Guinea has a rich diversity of coral life and 1,200 species of fish have been found. Also about 600 species of reef-building coral—the latter equal to 75 percent of the world’s known