Habropoda sinensis, Alfken, 1937

Tran, Ngat Thi, Engel, & Michael S., 2025, A contribution to the knowledge of Habropoda from Vietnam (Hymenoptera: Apidae), Raffles Bulletin of Zoology 73, pp. 125-152 : 131-132

sinensis species complex

Diagnosis. In both sexes, clypeus strongly convex medially; labrum subrectangular with small, shallow emargination; tergum I completely with long, dense, plumose setae; terga I–V with setal bands of dense plumose setae on apical border apically, those of females broader, thicker than those of males. In female, clypeus with T-inverted yellowish mark medially; pygidial plate with lateral margins gradually narrowed to basal ⅔, then slender on the remaining part and apex nearly rounded. In males, sternum VII strongly constricted at about midlength; discal (distal) portion diamond-shaped and covered with fine, short setae; sternum VIII concave apically and with some short setae. Male gonostylus with the dorsal process long, expanded gradually from base to apex, round apically with long setal tuft, and the ventral process obovate-shape, with dense setae.

Distribution. China, Taiwan, and Vietnam.

Included species. Habropoda sinensis Alfken, 1937 and H. taiwana Dubitzky, 2007 , new status (elevated to species rank owing to the significant differences in the hidden male sterna and morphological traits outlined in the key below).

Remarks. This is a complex of exceedingly similar species and which were previously considered subspecies of a single species ( Dubitzky, 2007). The discovery of a new form of this group from Vietnam clearly intermingled some of the more minor external morphological features but has a wholly unique form of the male terminalia, and is described as a new species. This led us to reinterpret the subspecies of H. sinensis , in which the male terminalia among the mainland and Taiwanese forms also differ significantly. We therefore believe this is a complex of three closely related species. Based on differences in illustrations from existing publications ( Lieftinck, 1974; Dubitzky, 2007), the Vietnamese population superficially resembles H. sinensis from mainland China in most characters but has the male antennal form of H. taiwana from Taiwan. Distinctions between the forms are outlined by Dubitzky (2007: 55–56) and it is clear that each population has unique forms to the male sterna VII and VIII. We consider the Vietnamese population a new species, raise the other two forms to species rank within the sinensis complex, and present here a key to the three species.