Biodiversity measurement is necessary to evaluate conservation alternatives and understand how to maximize biodiversity returns on conservation budgets. In the economics literature, most studies focus on species level diversity. Existing measures based on species' pairwise genetic differences do not perform optimally. This paper develops two new biodiversity measures within the same genetic framework. An axiomatic diagnosis for this class of measures is proposed and four biodiversity measures are then compared. Though the axiomatic comparison points towards a single "best" measure, it also indicates that the choice of measure should be dependent on the conservation problem at hand.