ostracoderm vs jawless fish

ostracoderm and jawless fish both are nouns.

Word	Noun	Adjective	Verb	Adverb
ostracoderm	Yes	No	No	No
jawless fish	Yes	No	No	No

As nouns, jawless fish is a hypernym of ostracoderm; that is, jawless fish is a word with a broader meaning than ostracoderm:

ostracoderm: extinct fish-like jawless vertebrate having a heavily armored body; of the Paleozoic
jawless fish: eel-shaped vertebrate without jaws or paired appendages including the cyclostomes and some extinct forms

Other hypernyms of ostracoderm include agnathan, jawless vertebrate.

ostracoderm (noun)	jawless fish (noun)
extinct fish-like jawless vertebrate having a heavily armored body; of the Paleozoic	eel-shaped vertebrate without jaws or paired appendages including the cyclostomes and some extinct forms