Widespread sympatry in a species-rich clade of marine fishes (Carangoidei)

Abstract The patterns of speciation in marine fishes are largely unknown, in part due to the deficiency of species-level phylogenies and information on species’ distributions, and partly due to conflicting relationships between species’ dispersal, range size, and patterns of co- occurrence. Most research on global patterns of marine fish speciation has focused on coral reef or pelagic species. Carangoidei is a clade of marine fishes including the trevallies, remoras, and dolphinfishes that utilize both coral reef and pelagic environments, spanning the ecologies of coral reef obligate and open-ocean species. We used sequence capture of 1314 ultraconserved elements (UCEs) from 154 taxa to generate a phylogeny of Carangoidei and its parent clade, Carangiformes. Age-range correlation analyses of the geographic distributions and divergence times of sister species pairs reveal widespread sympatry, with 73% of sister species pairs exhibiting a sympatric geographic distribution, regardless of node age, and most species pairs co-existing across large portions of their ranges. We also observe greater disparity in body size and water column depth utilization between sympatric than allopatric sister species. These and other ecological or behavioral attributes likely facilitate sympatry among the most closely related carangoid species, which exhibit sympatry at a larger taxonomic scale than has previously been described in marine fishes.