Pamphilius histrio group

The members of this species group are characterized as follows: upper part of head glabrous; facial crest in male very strongly swollen, rounded or very bluntly carinate; antennal flagellomere 1 1.0–2.5 × length of flagellomere 2; right mandible tridentate but incision between middle and apical teeth very shallow, or bidentate with only basal shoulder to apical tooth; left mandible tridentate with low middle tooth; wings hyaline, with dark marking only in P. betulae subgroup; forewing with cell C glabrous; femora entirely pale. Ovipositor sheath and its appendage various in shape. Male genitalia (e.g., Figs 67g, h, 103g, h, 122g, h): proximal ventral arm of gonostipes normal; apiceps broad and flattened; valviceps in lateral view rather long, apex directed straight or below, ventral margin more or less concave, with conspicuous dorsoapical process.

Eleven known species, one represented by two subspecies, are classified into five subgroups (Shinohara 2002b). In the Russian Far East and Korea, six species of four subgroups have been found.

Twenty-four sequences of six species (four subgroups) were treated in the COI analysis and six sequences of two species (two subgroups) were treated in the NaK analysis. In the COI analysis (Fig. 142), the P. brevicornis and P. gyllenhali subgroups were each retrieved as monophyletic with 100% UFBoot support and they formed a clade with 99% UFBoot support. However, two other subgroups ( P. betulae and P. histrio subgroups), though each recovered as monophyletic with 100% UFBoot support, did not form a monophyletic group with the P. brevicornis + P. gyllenhali subgroups. The sister group of the clade ( P. brevicornis + P. gyllenhali subgroups) was the P. inanitus group with 91% UFBoot support and the P. betulae subgroup was retrieved as having the sister relationship with the clade (( P. brevicornis + P. gyllenhali subgroups) + P. inanitus group) but with low UFBoot value of 84%. The P. histrio subgroup was distant from the other three subgroups and had the sister relationship with the P. lethierryi subgroup of the P. alternans group with very low UFBoot support (63%). In the NaK analysis (Fig. 156), two species (belonging to the P. brevicornis and P. gyllenhali subgroups) were recovered as a clade with 100% UFBoot support. In conclusion, the monophyly and the sister relationships of the P. brevicornis and P. gyllenhali subgroups were strongly supported but the monophyly of the P. histrio group as a whole was not supported by the present analyses.

The known host plants of this species group are Salicaceae ( Salix and Populus) and Betulaceae (Betula) .