Fig. 4.

Frequency of terms generated through searches of references database used here, embedded within six categories (A–F) considered here to represent a range of primary foci of continental comparative phylogeography. Those followed by an asterisk denote root terms that find any variation (e.g., allopat* will find allopatric, allopatry, allopatrically). The total frequencies of the six primary foci (G and H) differ because the latter was generated after removing three terms of overriding frequency, showing a more even distribution across the primary foci.