An order of actinopterygian (ray-finned) fishes that comprise, with the Beloniformes and Cyprinodonti-formes, the series Artherinomorpha. Atherinimorphs are more or less intermediate between typical soft-rayed and spiny-rayed fishes, but are not thought to be the ancestry of the latter. The order Atheriniformes, consisting of about 285 species in six families, are relatively small fishes, usually with an elongate body; opercular and preopercular margins lacking spines or serrations; lateral line absent or nearly so; usually two dorsal fins, with the first, if present, having weak spines; an anal fin larger than the soft dorsal fin and usually preceded by one spine; and usually abdominal pelvic fins, but subthoracic or absent in some (see family Phallostethidae below).