How are the swim bladder and inner ear connected in notopterids and hiodontids?

In notopterids and hiodontids, the swim bladder is connected to the auditory region of the skull through paired extensions. These extensions serve as a mechanism that likely improves the fish's hearing.1

In the African notopterid genus Papyrocranus, these extensions take the form of diverticula—outpocketings of the swim bladder—that actually penetrate the skull. This anatomical arrangement is a distinct feature within the osteoglossomorph group, contrasting with other members such as the suborder Osteoglossoidei, where the swim bladder is not connected to the skull.12