monotreme

[ mon-uh-treem ]

noun

any animal of the Monotremata, the most primitive order of mammals, characterized by certain birdlike and reptilian features, as hatching young from eggs, and having a single opening for the digestive, urinary, and genital organs, comprising only the duckbill and the echidnas of Australia and New Guinea.

Origin of monotreme

1825–35; <French monotrème<New Latin monotrema, assumed singular of Monotremata, neuter plural of monotrematusmonotrematous

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

How to use monotreme in a sentence

A wide interval seems to separate these intelligent mammals from the lower placentals, the marsupials and monotremes.
The Wonders of Life | Ernst Haeckel
With the exception of the atlas of Echidna the cervical vertebrae of Monotremes are without zygapophyses.
The Vertebrate Skeleton | Sidney H. Reynolds
Of the Monotremes Echidna has twelve caudal vertebrae, two of which bear irregular chevron bones.
The Vertebrate Skeleton | Sidney H. Reynolds
In Monotremes the ossicles, though distinctly mammalian in character, show a very low type of development.
The Vertebrate Skeleton | Sidney H. Reynolds
In Monotremes and most Marsupials the sternum does not present any characters of special importance.
The Vertebrate Skeleton | Sidney H. Reynolds

British Dictionary definitions for monotreme

monotreme

/ (ˈmɒnəʊˌtriːm) /

noun

any mammal of the primitive order Monotremata, of Australia and New Guinea: egg-laying toothless animals with a single opening (cloaca) for the passage of eggs or sperm, faeces, and urine. The group contains only the echidnas and the platypus

Origin of monotreme

C19: via New Latin from mono- + Greek trēma hole

Derived forms of monotreme

monotrematous (ˌmɒnəʊˈtriːmətəs), adjective

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Scientific definitions for monotreme

monotreme

[ mŏn′ə-trēm′ ]

Any of various mammals of the order Monotremata. Monotremes are the most primitive type of living mammal. They lay eggs and have a single opening (cloaca) for reproduction and elimination of wastes. The females have no teats but provide milk directly through the skin to their young. The only living monotremes are the duck-billed platypus, found in Australia and New Guinea, and the echidnas, found in New Guinea. Monotremes may have evolved already in the Jurassic Period, but the precise nature of their relationship to marsupials and placental mammals is disputed.

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