Criteria (adopted from Bolnick and Fitzpatrick (2007))

Strategy

1) Sister Species

Phylogenetic analysis

2) Complete reproductive isolation

Ratio of reproductive events leading to hybrid offspring

3) Overlapping geographic ranges

Calculating average geographic distance between all individuals of sister species

4) Allopatric/Parapatric alternative hypotheses

Rejecting alternative hypotheses using the combination of phylogenetic tracking and biogeographic data