Mammal-like occlusion in conodonts

Conodont element function and feeding mechanisms are of considerable paleob iological importance, yet many details remain poorly understood and specula tive. Analysis based on morphology, physical juxtaposition, and patterns of surface damage and microwear on pairs of Pa elements from individuals of I diognathodus indicates that these elements crushed food by rotational closu re, which brought the oral surfaces into complex interpenetrative occlusion . Other molariform conodont elements also functioned in this manner. Occlus ion of this complexity is unique among nonmammalian vertebrates, and is all the more surprising given that conodonts lacked jaws. In addition to enhan ced understanding of food processing in conodonts, our analysis suggests th at many details of conodont Pa element morphology, which underpin taxonomy and biostratigraphy, can now be interpreted in a paleobiological, functiona l context.