What animals are Australian placental mammals?

Answer 1

No, echidnas are not placental mammals. They are classified as monotremes. They are mammals as they feed their young on mothers' milk, but they lay eggs. The echidna is unique in this way as there is only one other monotreme known, the platypus. Echidnas do not have teats, but a milk patch through which milk seeps when they are feeding their hatched young.

Answer 2

Most of Australia's native mammals are marsupials, and it also has two species of monotremes (egg-laying mammals).

There are many marine mammals and all of these are placental. They include dolphins, and the dugong, or sea-cow.

The only terrestrial placental mammals native to Australia are bats, of which there are over 80 species, bush rats and native hopping mice (rodents, not marsupials), of which there are several species.

Dingoes are not truly native, not having originated here: they came with the Aborigines thousands of years ago, and for this reason are not necessarily considered to be truly native.