‘Enormously exciting’ fossils found in NSW opal field suggest Australia had ‘age of monotremes’

Discovery of ‘echidnapus’ and two more species show the furry egg-layers predated marsupials

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Some time about 100m years ago in what is now an Australian opal field, a weird, furry, egg-laying, rabbit-sized mammal was gliding through a waterhole across a massive polar floodplain.

This mammal – Opalius splendens but which scientists have thankfully blessed with the nickname “echidnapus” – was among the ancient descendants of one of the planet’s most unique orders of animals, the monotremes.