This problem concerns prey manipulation in osteoglossomorph fishes. Most members of this family possess a suite of apomorphic morphological modifications to the feeding apparatus: a bite between the bashiyal or "tongue" and the base of the skull. If structure and function are linked closely these taxa will share a common functional novelty associated with this "tongue-bite".
The use of the tongue-bite was documented by recording the electrical activity of the muscles involved and by analyzing high-speed films of prey manipulation by these fish.
It was found that the different taxa differed significantly in the function of the tongue-bite morphology.
Diagram of the skull of Notopterus to show the teeth on the bashiyal(BH) or "tongue" and on the base of the skull. The muscles that power the tongue bite are labelled EP,SH,PIM,AM, and HY. The pharyngeal jaws to the rear of the tongue bite are controlled by the muscles labelled PCe,AD5, and LE.