Tongue bite apparatus highlights functional innovation in a 310-million-year-old ray- finned fish

The paradigm is the established understanding of the evolution of feeding mechanisms in ray-finned fishes, specifically focusing on the development of the tongue bite. This includes the existing knowledge of the timing, anatomical variations, and phylogenetic distribution of this adaptation across different lineages.

This preprint presents a discovery within the existing paradigm of fish feeding evolution. The identification of a tongue bite apparatus in the Early Pennsylvanian †Platysomus parvulus extends the known occurrence of this feature earlier in the fossil record than previously documented. This discovery doesn't challenge the current paradigm but refines it by adding a new data point and prompting a re-evaluation of the evolutionary timeline and potential precursors to the more developed tongue bites seen in later lineages, like the †bobasatraniids. The research uses standard methods of comparative anatomy and phylogenetic analysis, operating within the accepted framework of evolutionary biology. The authors explicitly discuss their findings within the context of existing evolutionary models and propose a step-wise evolutionary trajectory for the tongue bite, illustrating how this research contributes to "normal science" by filling in gaps in our understanding and refining existing hypotheses within the dominant paradigm. The discovery has the potential to shift our understanding of early fish evolution and feeding adaptations within the broader paradigm, but does not constitute a paradigm shift itself.