Fig. 1.

(A) Six terrestrial biogeographic regions of the world, basically dating to Wallace (2), but this depiction (map modified with permission from ref. 4) with boundaries modified modestly and with proposed subregions (see original paper for additional terminology). Numbers refer to distribution of comparative phylogeographic studies of continental biotas using references database described further in text. (B) Growth of continental comparative phylogeographic studies 1992–2015, total and tabulated by biogeographic region using references database described further in text (numbers for 2015 not complete because database was downloaded from Web of Science in December 2015).