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Plants & CreaturesGreekEnglish

Monotreme

/ˈmɒnətriːm/noun

An egg-laying mammal, comprising the platypus and the echidnas.

The Greek roots

μόνος
mónos
single, alone
+
τρῆμα
trêma
hole, perforation

Literally: single hole

The story of the word

The platypus and the echidnas have one opening for urine, faeces and eggs, and early nineteenth-century anatomists named the group for precisely that plumbing: μόνος plus τρῆμα. Nothing in the name mentions the far stranger fact, that these are mammals which lay eggs and then sweat milk through the skin. τρῆμα reappears in trematode, the parasitic flukes, named for the sucker they hold on with.

How it travelled
Ancient Greek → Modern Latin → English
First recorded
1830s

Same family

monopolymonotonetrematodemonk

In a sentence

Only five monotreme species are alive today, all of them in Australia and New Guinea.

A monotreme egg is leathery rather than brittle.

Built on the same root

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