epixylon vs benthos

epixylon and benthos both are nouns.

Word	Noun	Adjective	Verb	Adverb
epixylon	Yes	No	No	No
benthos	Yes	No	No	No

As nouns, benthos is a hypernym of epixylon; that is, benthos is a word with a broader meaning than epixylon:

epixylon: organisms that are attached to submerged wood surfaces in aquatic ecosystems.
benthos: organisms (plants and animals) that live at or near the bottom of a sea, lake, river or stream

epixylon (noun)	benthos (noun)
organisms that are attached to submerged wood surfaces in aquatic ecosystems.	organisms (plants and animals) that live at or near the bottom of a sea, lake, river or stream
	a region including the bottom of the sea and the littoral zones