protacanthopterygian adjective 1noun 1forms 1 adjective1 •Of or from the superorder Protacanthopterygii of ray-finned fish.Rosen (1973) separated the stomiiforms (= Stomiatoidei) from other protacanthopterygian groups, placing them as the sister-group of all other neoteleosts (Eurypterygii). — 1996 noun1 •A fish of this superorder. formsprotacanthopterygians
