title: Microstructural variation in conodont enamel is a functional adaptation.
abstract: Recognition that conodonts were the earliest vertebrate group to experiment with skeletal biomineralization provides a window in which to study the origin and early evolution of this developmental system. It has been contended that the conodont skeleton comprised a classic suite of vertebrate hard tissues, while others suggest that conodont hard tissues represent divergent specializations within the early diversification of vertebrate hard tissues, supporting a view that the hard tissues of conodonts, particularly enamel, exhibit a range of microstructural variation beyond that seen in vertebrates. New evidence reveals that, although variable, conodont enamel microstructure is consistent between homologous portions of homologous dentitions. Although there is a correlation between morphology and microstructure, this belies a stronger correlation between the commonality of microstructure and 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.
authors.affiliation: School of Earth Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK. p.c.j.donoghue@bham.ac.uk
authors.forename: P C
authors.initials: PC
authors.lastname: Donoghue
mesh_terms: D000222:Adaptation, Physiological; D000818:Animals; D003743:Dental Enamel / Q000648:ultrastructure*; D008954:Models, Biological; D009805:Odontogenesis; D014714:Vertebrates / Q000502:physiology*