Definition of prototherian in English:

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Pronunciation: /ˌprəʊtə(ʊ)ˈθɪərɪən/


A mammal of the group Prototheria, which comprises the monotremes and their extinct relatives.
Example sentences
  • Extant mammals, including prototherians (egg-laying mammals) and therians (marsupial and placental mammals), probably last shared a common ancestor about 160 million years ago.


Relating to or denoting prototherians.
Example sentences
  • They had a common ancestor more recently than either had with the monotremes or, probably, any other prototherian group.
  • In his classification of prototherian mammals Hopson queried the allocation of Haramiyidae to the Multituberculata.
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