Mitogenomics and the sister of Salmonidae

Salmon, trout, char, grayling, whitefish and ciscoes are all members of Family Salmonidae and, whilst the monophyly of this group is not in doubt, determining which fishes are their closest relatives is a different story altogether. A new topology based on a mitogenomic study by Ishiguro et al. supports the hypothesis that the sister group of Salmonidae is Esociformes (e.g. pike, pickerel and mudminnows) rather than Osmeroidei (e.g. smelts, galaxiids and icefishes). This surprising discovery gives a new perspective on the evolution of many salmonid traits, including anadromy (the migration of fish from seawater to freshwater to spawn), the distribution of salmonid ancestors and previous morphology-based phylogenetic analyses.