Molecular data support separate scombroid and xiphioid clades

Molecular data (single copy nuclear DNA Tmo-4C4 and combined Tmo-4C4 and mitochondrial DNA cytochrome b) lead to the following conclusions about the inter-relationships of "scombroid" fishes. In both the single copy nuclear DNA (scnDNA) and combined molecular data sets, billfishes (Xiphioidei) and tunas and mackerels (Scombroidei) are separate clades. In the scnDNA parsimony clade, Pomatomus is basal to other scombroids. Sphyraena is excluded from the scombroids in all analyses, but only in the scnDNA analysis is Gasterochisma the basal scombrid. The sub-families Gasterochismatinae and Scombrinae and the tribe Scombrini (mackerels) are supported by both data sets, but the tribes Scomberomorini, Sardini, and Thunnini do not have molecular support. Morphological data place Allothunnus at the base of the Thunnini but the molecular data do not support this.