[mon-uh-treem] 
| 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. |
| mon·o·treme (mŏn'ə-trēm') n. A member of the Monotremata, an order of primitive egg-laying mammals restricted to Australia and New Guinea and consisting of only the platypus and the echidna. [From New Latin Monotrēmata, order name : mono- + Greek trēma, trēmat-, perforation; see terə-1 in Indo-European roots.] mon'o·trem'a·tous (-trěm'ə-təs) adj. |
| monotreme (mŏn'ə-trēm') Pronunciation Key
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. |