10900
20
1279 species
More than 4400 species
There are 22 different species of Tsetse flies in the world.
There is 60 different species of Kangaroo in Australia
Yes. There are many different species of kangaroos in Western Australia. Red kangaroos, in particular, are found throughout Western Australia.
No. Some dolphin species are common around Australia... but they are not Australian as such. There are many different dolphin species (over 40) But none of these are 'Australian'.
There are about 400 species of cockroaches in Australia, most of which are native to the continent. see the related link below for more information.
Yes there are many species of amphibians in Australia. Australia has about 230 species of native frogs, but no salamanders, newts or axolotls.
1
There are over 30 species of yabby, a type of freshwater crayfish, in Australia. Different species may be known by various other names, such as marron, koonacs and gilgies. In addition there are another 70 or so freshwater crayfish which do not belong to the yabby genus.
There are about 3000 species worldwide and 150 species in Australia.
Over a million species or instects are described and many more are not. The answer is probably millions. A link is provided to the Wikipedia article on insects. Surf on over and at least read the first paragraph.