acanthopterygious,a.Zool.|əˌkænθɒptəˈrɪdʒəs| [f. acanthopterygii + -ous.] Having spine-like rays in the dorsal fin; spiny-finned:—an epithet of a group of fishes. 1833Pen. Cycl.s.v.Acanthopterygii, M. Cuvier divided the Acanthopterygious Fishes into fifteen families.