(zoology) Any of the ray-finned fish of the taxonomic class Actinopterygii.
2004, M. L. J. Stiassny, E. O, Wiley, G. D. Johnson, M. R, de Carvalho, 24: Gnathostome Fishes, Joel Cracraft, Michael J. Donoghue (editors), Assembling the Tree of Life, page 416,
The most basal of living actinopterygians are the bichirs (Polypteridae), a small group (11 spp.) of African fishes previously thought to be related to the lobefin fishes (sarcopterygians), or to form a third group.
adjective
Of the nature of fish of the class Actinopterygii.