monotreme

[ mon-uh-treem ]

noun

1. 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.

monotreme

/ ˈmɒnəʊˌtriːm; ˌmɒnəʊˈtriːmətəs /

noun

1. 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

monotreme

/ mŏn′ə-trēm′ /

1. 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.

Derived Forms

• monotrematous, adjective

Word History and Origins

Origin of monotreme¹

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

Word History and Origins

Origin of monotreme¹

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

Example Sentences

Professor Flannery said the research reveals that 100 million years ago, Australia was home to a diversity of monotremes, of which the platypus and the echidna are the only surviving descendants.

From Science Daily

Fossilised pieces of the animal's jaw bone were found in opal fields in northern New South Wales, alongside evidence of several other ancient and now extinct monotreme species.

From BBC

This echidna species is so special because it is one of only five remaining species of monotremes, the sole guardians of this remarkable branch of the tree of life.

From Science Daily

The southern tribosphenic mammals, he says, either died out or became monotremes, a family of mammals that includes the platypus and echidna.

From New York Times

The findings, detailed in 11 studies published in the journal Science, involved placentals, by far the world's most common mammalian assemblage, known for giving birth to well-developed babies, and not egg-laying monotremes or pouched marsupials.

From Reuters