Microstructural variation in conodont enamel is a functional adaptation

Recognition that conodonts were the earliest vertebrate group to experiment with skeletal biomineralization provides a window in which to study the or igin and early evolution of this developmental system. It has been contende d that the conodont skeleton comprised a classic suite of vertebrate hard t issues, while others suggest that conodont hard tissues represent divergent specializations within the early diversification of vertebrate hard tissue s, supporting a view that the hard tissues of conodonts. particularly ename l, exhibit a range of microstructural variation beyond that seen in vertebr ates. New evidence reveals that, although variable, conodont enamel microst ructure is consistent between homologous portions of homologous dentitions, Although there is a correlation between morphology and microstructure, thi s belies a stronger correlation between the commonality of microstructure a nd dental function. The enamel of conodonts evolved in response to changes in dental function and differentiation of the microstructural layer into a number of enamel types and can be linked to dental occlusion, heterodonty, a permanent dentition, enamel thickness and, probably above all, the small size of the dental elements.