  We derive an invertible transform linking two widely used measures of species
diversity: phylogenetic diversity and the expected proportions of segregating
(non-constant) sites. We assume a bi-allelic, symmetric, finite site model of
substitution. Like the Hadamard transform of Hendy and Penny, the transform can
be expressed completely independent of the underlying phylogeny. Our results
bridge work on diversity from two quite distinct scientific communities.
