Variation in quantitative measures of enamel prisms from different species as assessed using confocal microscopy

This study presents a statistical analysis of variability in six measures of enamel prism and ameloblast size and spacing gathered using confocal microscopy, and applies the results to a consideration of appropriate sampling strategies for taxonomic analyses. Variability within individuals was examined within depth series. Individual variability was also assessed within a nested analysis of variation for prism measurements between micrographs, specimens and species. While sample depth was not often significantly associated with differences in prism and ameloblast measures, there was significant variation between micrographs taken from the same region of a tooth. The highest levels of variation were found between species, while variation between conspecific individuals was relatively small. These results demonstrate that data gathered from several micrographs are likely to be representative of a specimen, but that several micrographs of a single specimen will rarely illustrate the range of variation contained within a species. It is essential for systematic and taxonomic analyses that several micrographs be used to characterize an individual. It is also recommended that samples from several individuals be used to characterize species. While data from isolated specimens is often of great interest, taxonomic or systematic conclusions based on isolated individuals should be approached cautiously.