pygmy chimpanzee vs chimpanzee

pygmy chimpanzee and chimpanzee both are nouns.

Word	Noun	Adjective	Verb	Adverb
pygmy chimpanzee	Yes	No	No	No
chimpanzee	Yes	No	No	No

As nouns, chimpanzee is a hypernym of pygmy chimpanzee; that is, chimpanzee is a word with a broader meaning than pygmy chimpanzee:

pygmy chimpanzee: small chimpanzee of swamp forests in Zaire; a threatened species
chimpanzee: intelligent somewhat arboreal ape of equatorial African forests

Other hypernyms of pygmy chimpanzee include chimp, Pan troglodytes.

pygmy chimpanzee (noun)	chimpanzee (noun)
small chimpanzee of swamp forests in Zaire; a threatened species	intelligent somewhat arboreal ape of equatorial African forests