Taxonomic review of Argentine mackerel Scomber japonicus (Houttuyn, 1782) by phylogenetic analysis

Taxonomically, Argentine mackerels were first considered as Scomber japonicus marplatensis and later as Scomber japonicus Houttuyn 1782, although, in the last years, different studies have suggested that South Atlantic mackerel species belongs to Scomber colias Gmelin 1789. These latter results, incorporated in the main fish databases (FishBase and Catalog of Fishes), promoted a phylogenetic study using cytochrome c oxidase I (COI) gene sequences taken from the Barcode of Life (FISH-BOL) database. Thus, 76 sequences of S. japonicus, S. colias, S. australasicus and S. scombrus from different regions were used; including 3 from Sarda sarda as outgroup. Among S. japonicus selected sequences are those corresponding to the Argentine mackerels collected in 2007. Phylogenetic trees were obtained by neighbor joining and maximum likelihood methods and a network of haplotypes was reconstructed to analyze the relationship between species. The results showed the clear differentiation of S. australasicus, S. scombrus and S. japonicus from the Pacific while S. japonicus from Argentina was included in the S. colias group, with genetic differences corresponding to conspecific populations (0.1%). Four of the five Argentine specimens shared the same haplotype with S. colias, and none were shared with S. japonicus from the Pacific. These results suggest that the current specific name of Argentine mackerel S. japonicus should be changed to S. colias, in agreement with several genetic studies carried out with species of the genus Scomber.