Monotreme (7)

I believe the answer is:

echidna

'monotreme' is the definition.
(echidna is a kind of monotreme)

This is all the clue.

(Other definitions for echidna that I've seen before include "This insectivore" , "Toothless type" , "Little animal" , "Prickly creature" , "Insectivorous mammal" .)

I've seen this clue in the Sydney Morning Herald.

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