colobus vs guereza

colobus and guereza both are nouns.

Word	Noun	Adjective	Verb	Adverb
colobus	Yes	No	No	No
guereza	Yes	No	No	No

As nouns, guereza is a hyponym of colobus; that is, guereza is a word with a more specific, narrower meaning than colobus:

colobus: arboreal monkey of western and central Africa with long silky fur and reduced thumbs
guereza: a colobus monkey with a reddish brown coat and white silky fringes down both sides of the body

Other hyponyms of colobus include Colobus guereza.

colobus (noun)	guereza (noun)
arboreal monkey of western and central Africa with long silky fur and reduced thumbs	a colobus monkey with a reddish brown coat and white silky fringes down both sides of the body