Echidnas and Platypus
Echidnas and the platypus are part of the Monotremata family. There are only three species of monotreme in the world - the platypus and two species of echidnas, one of which is restricted to the New Guinea highlands.
Monotremes have lower body temperatures than other mammals and have legs which extend out, then vertically below them. These features, together with their egg-laying, are more like that of a lizard than a mammal.
Read about a fungal infection affecting the platypus in Tasmania.