How are protacanthopterygians different from lower teleost fishes and neoteleosts?

The superorder Protacanthopterygii occupies a distinct evolutionary position as a basal stock of modern bony fishes. Their classification relative to other groups is defined by their intermediate level of advancement.1

• Compared to lower teleosts: Protacanthopterygians are considered more advanced than "lower" teleosts, such as osteoglossomorphs and ostariophysans.1
• Compared to neoteleosts: While they represent a foundational group that provided the evolutionary raw material for many modern lineages, they are not as advanced as the [neoteleosts].1

The group, which includes salmons, trouts, and pikes, is characterized by a generalized morphology, such as streamlined bodies and fins supported by soft rays rather than spines. Their evolutionary significance lies in the trends that developed during the Late Mesozoic Era, which served as a precursor to the diversity seen in most modern bony fishes.231