Duckbilled platypus and Monotreme

Duckbilled platypus noun - Small densely furred aquatic monotreme of Australia and Tasmania having a broad bill and tail and webbed feet; only species in the family Ornithorhynchidae.

Monotreme and duckbilled platypus are semantically related. In some cases you can use "Monotreme" instead a noun phrase "Duckbilled platypus".

Monotreme noun - The most primitive mammals comprising the only extant members of the subclass Prototheria.

Duckbilled platypus and monotreme are semantically related. Sometimes you can replace phrase "Duckbilled platypus" with "Monotreme", this terms are similar.