Costia necatrix vs mastigophore

Costia necatrix and mastigophore both are nouns.

Word	Noun	Adjective	Verb	Adverb
Costia necatrix	Yes	No	No	No
mastigophore	Yes	No	No	No

As nouns, mastigophore is a hypernym of Costia necatrix; that is, mastigophore is a word with a broader meaning than Costia necatrix:

Costia necatrix: a flagellate that is the cause of the frequently fatal fish disease costiasis
mastigophore: a usually nonphotosynthetic free-living protozoan with whiplike appendages; some are pathogens of humans and other animals

Other hypernyms of Costia necatrix include flagellate, flagellate protozoan, flagellated protozoan, mastigophoran.

Costia necatrix (noun)	mastigophore (noun)
a flagellate that is the cause of the frequently fatal fish disease costiasis	a usually nonphotosynthetic free-living protozoan with whiplike appendages; some are pathogens of humans and other animals