Parvimyrma sangi ^HNS sp. nov.

(Figs. 1-10)

Holotype worker: Tay Yen Tu N. P., 21°10’11”N, 106°43’06”E, 435 m alt., Bac Giang Prov., N. Vietnam, 28 May 2004 (K. Eguchi leg., colony Eg04-VN-138) [IEBR]. Paratypes: 42 pinned and 2 slide-mounted workers from the same colony as holotype [IEBR, BMNH, MCZC, MHNG, MNHA, ACEG].

Worker description. Tiny species with characteristics given in the generic diagnosis. Body pale yellowish brown, much depigmented, covered with short standing hairs. Head in full-face view roughly elongaterectangular, in profile thin dorsoventrally with flattened dorsal and ventral margin; the dorsum of head weakly rugoso-reticulate except almost smooth anteromedian part of frons; the lateral face of head weakly rugosoreticulate; clypeus largely smooth, with its anteromedian margin truncate; outer surface of mandible smooth; mandibular teeth triangular and sharp, gradually reduced in size from the apical teeth to the basal teeth; antennal scape short, reaching only 7/10-3/4 of the distance from the anterior margin of clypeus to the posterior margin of head (Fig. 2); antennal segments III -IX much shorter than broad; the apical antennal segment ca. 3 times as long as the preapical segment; mesosoma smooth except lower part of mesopleuron which is very weakly reticulate; gaster entirely smooth.

Worker measurements and indices. Holotype: HL 0.37 mm, HW 0.26 mm, SL 0.21 mm, ML 0.42 mm, FL 0.19 mm, CI 71, SI 81, FI 71. Paratypes (n=4): HL 0.37 mm, HW 0.26-0.27 mm, SL 0.21 mm, ML 0.40-0.41 mm, FL 0.19-0.20 mm, CI 71-73, SI 78-79, FI 71-74.

Bionomics. The type series was obtained from one of ten cheese bait traps (small plastic tubes with several entrances containing powdered cheese as bait) buried ca. 10 cm underground in a well-developed forest at ca. 435 m alt. The circumstantial evidence as well as its morphological features (depigmentation and flat body without eyes) suggest that Parvimyrma sangi ^HNS is a subterranean nester and forager.