crossopterygian vs lobefin

crossopterygian and lobefin both are nouns.

Word	Noun	Adjective	Verb	Adverb
crossopterygian	Yes	No	No	No
lobefin	Yes	No	No	No

As nouns, crossopterygian and lobefin are synonyms defined as:

crossopterygian and lobefin: any fish of the order Crossopterygii; most known only in fossil form

Other synonyms of crossopterygian include lobe-finned fish.

crossopterygian (noun)	lobefin (noun)
any fish of the order Crossopterygii; most known only in fossil form	any fish of the order Crossopterygii; most known only in fossil form