Revision of the Japanese species of Metanipponaphis (Hemiptera: Aphididae) and its allied genera

Species of the aphid genus Metanipponaphis (Hormaphidinae: Nipponaphidini) form galls on Distylium racemosum and migrate to Castanopsis trees. Japanese species of Metanipponaphis and its allied genera were revised based on molecular phylogenetic analyses. The genera Monzenia and Lithoaphis were united with Metanipponaphis, and Metanipponaphis was adopted as the valid name for the genus. Neonipponaphis shiiae was found belonging to another clade containing Nipponaphis species. The gall or primary-host generation of M. shiicola was recorded for the first time. Little difference was found in their nucleotide sequences between M. cuspidatae, a host-alternating species, and M. ihai, a monoecious species on D. racemosum. The molecular phylogenetic analyses also showed that the monoecious M. globuli is a sister species of the host-alternating M. shiicola. The taxonomy and biology of six Metanipponaphis species and N. shiiae were reviewed, with keys to the species based on the apterous adults and first-instar nymphs on Castanopsis spp.