Inter‐ocean dispersal is an important mechanism in the zoogeography of hakes (Pisces: Merlucciusspp.)

• Published in: Journal of Biogeography
• Main Authors: Grant, W. Stewart, Leslie, Robin W.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2001
• Subjects: Hake; Pacific; Southern Ocean; North Atlantic
• Online Access: http://dx.doi.org/10.1046/j.1365-2699.2001.00585.x; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1046%2Fj.1365-2699.2001.00585.x; https://onlinelibrary.wiley.com/doi/pdf/10.1046/j.1365-2699.2001.00585.x

Aim To present new genetic data and to review available published genetic data that bear on the phylogeny of hakes in the genus Merluccius . To construct a zoogeographical model from a summary phylogenetic tree with dated nodes. To search for an explanation of antitropical distributions in hakes. To assess peripheral isolate, centrifugal and vicariance models of speciation in view of the molecular phylogeny and zoogeography of hakes. Locations Northern and southern Atlantic Ocean, eastern Pacific Ocean, South Pacific Ocean. Methods Electrophoretic analysis of 20 allozyme loci in 10 species of hakes. Phylogenetic tree construction with parsimony and bootstrap methods. Reanalysis of previous genetic data. Analysis of zoogeographical patterns with geographical distributions of molecular genetic markers. Results Phylogenetic analyses of new and previous allozyme data and previous mitochondrial DNA data indicate a deep genetic partition between Old‐ and New‐World hakes with genetic distances corresponding to 10–15 Myr of separation. This time marks a widening rift between Europe and North America and a rapid drop in ocean temperatures that subdivided an ancestral population of North Atlantic hake. Two Old‐World clades spanning the equator include pairs of sister taxa separated by tropical waters. Divergence times between these pairs of sister‐taxa variously date to the early Pliocene and late Pleistocene. Amongst New‐World hakes, pairs of sister taxa are separated by equatorial waters, by the Southern Ocean, and by the Panama Isthmus. These genetic separations reflect isolation by the rise of the Isthmus 3–4 Ma and by Pliocene and Pleistocene dispersals. Pairs of species occurring in sympatry or parapatry in six regions do not reflect sister‐species relationships, but appear to reflect allopatric divergence and back dispersals of descendent species. Some geographically isolated regional populations originating within the last few hundreds of thousands of years merit subspecies designations. Conclusions Vicariance ...