Taxonomic revision of the T uberculatus quercicola group ( H emiptera: A phididae: D repanosiphinae), myrmecophilous aphids associated with Q uercus species, based on morphometric and molecular phylogenetic studies

In this paper, we revised the taxonomy of the T uberculatus quercicola group, myrmecophilous drepanosiphine aphids that are associated with Q uercus dentata and Q . crispula in J apan, based on morphometry and molecular phylogeny. This species group has been recognized as T . quercicola with some junior synonyms. Morphometric analysis of 11 morphological characters divided the group into three clusters: (i) the Q . crispula ‐associated population; (ii) the central H okkaido group of the Q . dentata ‐associated population; and (iii) the eastern H okkaido group of the Q . dentata ‐associated population. Most parsimony and maximum likelihood analyses of the mitochondrial cytochrome oxidase subunit I COI gene indicated that samples of the T . quercicola group are separated, with high bootstrap supports, into two monophyletic groups that are associated with either Q . dentata or Q . crispula . However, no genetic differentiation was detected between the central Hokkaido group and the eastern Hokkaido group of the Q . dentata ‐associated population. These results led us to conclude that populations associated with Q . dentata are genetically and morphologically distinct from those associated with Q . crispula , and thus they are in a full specific status. On the other hand, we treated the two local groups of the Q . dentata ‐associated population as local races based on morphology. We formally redescribed the Q . crispula ‐associated and Q . dentata ‐associated populations under the names T . quercicola and T . macrotuberculatus stat. rev., respectively.