Parvimyrma Eguchi & Bui, 2007

Eguchi, K., Viet, B. T. & Yamane, S., 2011, Generic synopsis of the Formicidae of Vietnam (Insecta: Hymenoptera), Part I - Myrmicinae and Pseudomyrmicinae., Zootaxa 2878, pp. 1-61 : 23

Parvimyrma Eguchi & Bui , 2007

Taxonomy. The genus Parvimyrma was established for a single species, P. sangi , is placed in the Solenopsis genus group (sensu Bolton 1987, 2003). The 11-segmented antenna and the distinctly 5-toothed triangular mandible are the only features that distinguish Parvimyrma from Solenopsis , the morphologically closest genus.

Worker monomorphic; frontal lobe in full-face view only partially concealing torulus, not extending posteriorly as a frontal carina; antennal scrobe absent; posteromedian portion of clypeus narrowly inserted between frontal lobes; median clypeal seta well developed; 1st paracarinal seta well developed; mandible triangular, overlapping but not crossing over at full closure, with 5 distinct teeth on masticatory margin but without any teeth/ denticles on basal margin; trulleum open; hypostoma with a conspicuous lateral tooth just mesal to each mandibular base; anterior margin of labrum broadly concave medially; palpal formula 2,2; antenna 11-segmented, with 2- segmented club; apical antennal segment much longer than preapical segment; eye completely absent; promesonotum in lateral view low and almost flat or very weakly convex dorsally; promesonotal suture completely absent dorsally; metanotal groove relatively shallowly impressed dorsally; meso- and metatibial spur absent; propodeum unarmed but with a narrow cuticular rim on each posterolateral corner of dorsum; rim running downward and connecting with propodeal lobe; propodeal lobe low and round; propodeal spiracle small; metapleural gland large; petiole pedunculate anteriorly and with distinct node; peduncle with a small anteroventral process; postpetiole much shorter than petiole, in dorsal view a little broader than petiolar node, narrowly attached to anteriormost end of gaster; abdominal tergite IV (= gastral tergite I) broadly overlapping sternite IV on ventral surface of abdomen; gastral shoulder present; sting poorly developed.

The worker of Parvimyrma is similar to those of Solenopsis and Oligomyrmex (see distinguishing characters under Oligomyrmex ). However, in the worker of Solenopsis the masticatory margin of the mandible bears an apical tooth followed by 2 distinct teeth and then one or more small or inconspicuous denticles, and the antenna is 9- or 10-segmented.

Vietnamese species. Only one species has been described from Vietnam: sangi Eguchi & Bui (Type locality: Tay Yen Tu).

Bionomics. The type series of Parvimyrma sangi was collected with a bait trap (small plastic tubes with several entrances containing powdered cheese as bait) buried approximately 10 cm underground in a well-developed forest at around 435 m alt. This circumstantial evidence as well as the species morphological features (depigmentation, a flat body and no eyes) suggests that this species is a subterranean nester and forager (Eguchi & Bui 2007).