methanogen vs archaeobacteria

methanogen and archaeobacteria both are nouns.

Word	Noun	Adjective	Verb	Adverb
methanogen	Yes	No	No	No
archaeobacteria	Yes	No	No	No

As nouns, archaeobacteria is a hypernym of methanogen; that is, archaeobacteria is a word with a broader meaning than methanogen:

methanogen: archaebacteria found in anaerobic environments such as animal intestinal tracts or sediments or sewage and capable of producing methane; a source of natural gas
archaeobacteria: considered ancient life forms that evolved separately from bacteria and blue-green algae

Other hypernyms of methanogen include archaebacteria, archaebacterium, archeobacteria.

methanogen (noun)	archaeobacteria (noun)
archaebacteria found in anaerobic environments such as animal intestinal tracts or sediments or sewage and capable of producing methane; a source of natural gas	considered ancient life forms that evolved separately from bacteria and blue-green algae