How do gadiform fishes differ in body shape and fin spines from many other paracanthopterygians?

Gadiform fishes, which include codfishes, differ from many other paracanthopterygians primarily through their body shape and the reduction of their fin spines.1

Regarding their physical structure, gadiforms are characterized by an elongate body shape. In contrast, other members of the superorder exhibit more diverse forms, such as the flattened heads of Batrachoidiformes or the specialized, often globular or compressed shapes found in Lophiiformes. Additionally, while some paracanthopterygians possess distinct spinous dorsal fins—such as the small anterior fin with spines found in toadfishes—gadiforms are noted for having very reduced fin spines.12

Furthermore, the arrangement of their fins is often distinct; for example, some deep-sea cods and codfishes feature a unique configuration of three dorsal fins and two anal fins, whereas other groups like the macrourids are distinguished by a long, tapering tail.2