it’s only ordinary on the outside. The skull is unique, but like al vertebrates shares a long list of traits with related taxa.
Gadus morhua (Linneaus 1758) is the Atlantic cod, nesting between two open ocean predators, Coryphaena and Rachycentron. Instead of one long dorsal fin, it is split in three. The anal fin is split in two. The chin has a barbel. The postparietal forms a long crest that divides the parietal. The naris is a long opening from snout tip nearly to the orbit. Note the elongate postfrontal (orange) and hyomandibular (dark green) with accessory processes.
Linnaeus C von 1758. Systema naturæ per regna tria naturæ, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Tomus I. Editio decima, reformata.