Crossopterygian \Cros*sop`ter*yg"i*an\ (kr?s-s?p`t?r-?j?-a]/>n), a. (Zo["o]l.) Of or pertaining to the Crossopterygii. -- n. One of the Crossopterygii.
crossopterygian n : any fish of the order Crossopterygii; most known only in fossil form [syn: {lobefin}, {lobe-finned fish}]