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单词 monotreme
释义

monotreme

/ˈmɒnə(ʊ)triːm /
noun Zoology
A primitive mammal that lays large yolky eggs and has a common opening for the urogenital and digestive systems. Monotremes are now restricted to Australia and New Guinea, and comprise the platypus and the echidnas.
  • Order Monotremata and subclass Prototheria: two families.
There are only three living monotremes, the duck-billed platypus and two species of echidna, or ‘spiny anteaters’, such as the one shown at right....
  • Placental and marsupial mammals are more closely related to one another than to the third living group of mammals, the monotremes.
  • The Australian fossil record of monotremes also includes some quite good Miocene and Pleistocene fossils of giant echidnas.

Origin

Mid 19th century: from mono- 'single' + Greek trēma 'hole'.

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更新时间:2024/11/13 15:22:54