Anatomical and other traits commonly found in this superorder are: more than 24 vertebrae, epicentral cartilages, one supraorbital bone, and a mesocoracoid, an adipose fin, and (often prominent) glossohyal teeth.

However, they usually lack a protrusible upper jaw, a gular plate, and proximal forking of the intermuscular bones.

[1] As mentioned initially, one of the closest relatives of the Protacanthopterygii are the Otocephala, which include such different fishes as carp, catfish, and herrings in superorders Clupeomorpha and Ostariophysi.

[2] In recent times, a trend exists to split the Osmeriformes in two, as their supposed suborders do not seem to be particularly closely related among the Protacanthopterygii.

And as it seems, the superorders Cyclosquamata and Stenopterygii, which contain some bizarre apomorphic forms, are so closely related to the "traditional" Protacanthopterygii as to be included therein.

As regards the latter, it is an entirely fossil group and may well be an invalid paraphyletic assemblage of ancient Teleostei, and in part may indeed belong in the Protacanthopterygii sensu lato.

[5] Lepidogalaxiiformes (salamanderfish) Argentiniformes (marine smelts) Galaxiiformes (white bait and mudfishes) Esociformes (pike) Salmoniformes (salmon, trout) Stomiiformes (dragonfish) Osmeriformes (smelt) Ateleopodidae (jellynoses) Aulopiformes (lizardfish) Myctophiformes (lanternfish) Acanthomorpha