Looking for patterns through time and space
Figure modified from Hodge et al., 2014 showing recent divergence estimates for sister-species from different ocean basins (grey bar) and biogeographical regions (coloured circles correspond to coloured regions on map).
My research has identified temporal and biogeographical patterns of species-level divergence that are consistent across four of the major coral reef fish families, the Chaetodontidae, Epinephelidae (formerly Serranidae), Labridae, and Pomacanthidae. For example, despite differing geological histories, all major ocean basins have supported recent species divergence. In contrast, species endemic to the Red Sea and Hawaiian Islands have vastly different age structures, suggesting different underlying evolutionary processes.
Figure from Hodge et al., 2014 showing steady divergence of species endemic to the Red Sea over the past ~16 million years (top) in contrast to two waves of divergence of species endemic to the Hawaiian Islands (bottom).
In a forthcoming article, my co-author and I outline the relative importance of biogeographical barriers in the divergence of reef fish species and map areas of geographical range overlap among sister-species. We describe the likely mechanism of a previously understudied biogeographical barrier in the Indian Ocean and show that it accounts for a substantial portion of recent reef fish divergences. Additionally, this work showed that the area of highest coral reef fish biodiversity also contains the largest number of sympatric sister-species. This supports the area as a centre of overlap and a evolutionarily dynamic region with a complex environment capable of sustaining closely related species in sympatry.
Figure from a forthcoming paper showing biogeographical barriers with corresponding splits between allopatric sister-species.
Figure excerpt from a forthcoming paper showing the concentration of sympatry among sister-species in the area concordant with the centre of coral reef fish biodiversity.