THE INS AND OUTS OF CONIFORM CONODONTS: INSIGHTS INTO FEEDING BEHAVIOR USING 2D AND 3D ANALYSIS

Predation is potentially one of the most impactful evolutionary traits to have ever developed. Conodonts, an extinct group of early vertebrates, developed the first phosphatic dental tools, known as elements. Elements ranged from simple coniform types to more complex morphologies, predominantly in more derived species. Unlike the teeth of other vertebrates, these continuously grew throughout their lifetime by the periodic accretion of new lamellar tissues. This unique growth process continuously records chemical and physical characteristics throughout the animal´s lifespan which, when accessed, gives insight into the animal’s ecology. Multiple lines of evidence, such as microwear studies and growth allometry, indicate that adult- derived conodonts fed as predators and/or scavengers. There is little indication how this feeding strategy developed in their evolution. This can be only elucidated by reaching to the earliest conodonts, which had coniform elements. Previous modelling of element position and mechanical properties indicate they were capable of processing or manipulation of food. A direct test would be provided through evidence of tissue damage and its chemical composition. This research focuses on samples of the coniform genus Proconodontus (Cambrian and Ordovician) and Panderodus (Silurian). Here we employ Backscatter electron (BSE) imaging, energy-dispersive X-Ray spectroscopy (EDX) and synchrotron radiation X-ray tomographic microscopy (SRXTM) data to identify and compare growth dynamics, microwear and chemical sclerochronology recorded within their unique mode of growth. Our results have direct implications not just for understanding the feeding mode of early conodonts but also the origination of predation in the earliest vertebrates in the fossil record.