Mammal-like occlusion in conodonts

—Conodont element function and feeding mechanisms are of considerable paleobiological importance, yet many details remain poorly understood and speculative. Analysis based on morphology, physical juxtaposition, and patterns of surface damage and microwear on pairs of Pa elements from individuals of Idiognathodus indicates that these elements crushed food by rotational closure, which brought the oral surfaces into complex interpenetrative occlusion. Other molariform conodont elements also functioned in this manner. Occlusion of this complexity is unique among nonmammalian vertebrates, and is all the more surprising given that conodonts lacked jaws. In addition to enhanced understanding of food processing in conodonts, our analysis suggests that many details of conodont Pa element morphology, which underpin taxonomy and biostratigraphy, can now be interpreted in a paleobiological, functional context. Philip C. J. Donoghue* and Mark A. Purnell. Department of Geology, University of Leicester, University Road, Leicester LE1 7RH, United Kingdom. E-mail: [email protected] and [email protected] *Previous address: School of Earth Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom Accepted: 20 September 1998