( Figs 1–7)
Material examined. Holotype, 1 ♀, CHINA: Tibet, Changdu City, Mangkang County, Rumei Town, Jueba Village, 29°34′51″N, 98°18′12″E, 3240m, 23.VII.2014, Tingjing Li & Chunfa Chen. Paratype: 1 ♀, same label as holotype.
Diagnosis. Female ( Fig. 1). This species differs from other members of the genus by the following combination of characters: clypeus punctate and interspaces between punctures on lateral side somewhat striate ( Fig. 2), dorsal surface of propodeum ( Fig. 6) with thin longitudinal striae on the basal and lateral half and irregularly reticulate on the apical portion (dorsal surface of propodeum almost uniform and regularly reticulate in D. aurantiacus) and T2–T4 with apical lamella short, not reflexed ( Fig. 7).
Description. Female ( Fig. 1). Body length 12.4–14.2 mm, fore wing length 11.2–12.2 mm. Black, with the following parts orange: two spots on the base of mandible and inner upper margin of antennal socket, large spot on apical half of clypeus, half of dorsolateral surface of pronotum, apical bands on both T1 and T2 ( Figs 1, 2); wings brown, veins dark brown ( Fig. 1).
Head. Head in frontal view as wide as high ( Fig. 2), with brown setae and dense punctures, length of setae about 2× as long as posterior ocellar diameter ( Fig. 3); mandible with four teeth; clypeus punctate and interspaces between punctures on lateral side somewhat striate, 1.5× as wide as high, its apical margin almost truncated, width of truncation 0.3× width of clypeus between inner eye ( Fig. 2); gena as wide as eye; punctures on vertex and gena slightly sparser than those on frons; occipital carina developed at lateral side ( Fig. 3); antennal scape with small punctures, 2.7× as long as its width, A3 1.1× as long as its maximum width, A4–A11 wider than long, A12 bullet-shaped ( Fig. 4).
Mesosoma. Mesosoma about 1.5× as long as wide, with setae and punctures; pronotal carina complete, pronotum with coarse punctures, its lateral low surface with weak striae ( Fig. 5); mesoscutum in lateral view weakly convex ( Fig. 5), with dense punctures and area between punctures slightly striate ( Fig. 1); notaulix complete, posterior area between the notaulices weakly punctate ( Fig. 1); tegula smooth on center portion, its anterior and posterior lobes punctate, and its posterior lobe sharp and developed exceeding parategula posteriorly; scutellum with medial longitudinal furrow and punctures ( Fig. 6); dorsal portion of mesopleuron coarsely punctate and area between punctures more or less carinate and ventral one sparsely punctate and area between punctures smooth ( Fig. 5); metapleuron with weak and oblique striae in dorsal portion and without distinctly striae and punctures in ventral one ( Fig. 5); propodeum dull, bearing lateral carina, with densely longitudinal and thin striae on basal half of dorsal surface and irregularly reticulate striae on apical half, posterior surface with median longitudinal carina and irregular striae ( Fig. 6), and its lateral surface with dense, weak and oblique striae ( Fig. 5).
Metasoma. T1 with coarse punctures, those on lateral side denser and bigger, and interspaces between punctures somewhat striate ( Figs 1, 7), T1 about 2× as long as its maximum width, widening at one-fifth of the tergum from base, in lateral view abruptly swollen from near base; apexes of T2–T4 with very short lamellae, not reflexed ( Fig. 7); T2 about 1.1× as long as wide dorsally, punctures on T2 minute and distinctly smaller than those of T1, those on basal portion dense and then gradually sparser from base to apex, T2 not petiolate at base ( Figs 1, 7); punctures on S2 larger than those on T2, and those on lateral portion slightly denser; punctures on T3–T6 slightly larger than those on T2.
Variation. S2 with apical interrupted band in paratype.
Male. Unknown.
Distribution. China ( Tibet).
Remarks. This species is allied to D. aurantiacus Nguyen, 2016 from Vietnam by similar color pattern, mesoscutum with dense punctures ( Fig. 1), and T 1 in lateral view abruptly swollen from near base.
Etymology. The specific name brevilamellatus is from the Latin brev- (= short) + lamellatus (= lamella), which refers to T2 – T4 with apical short lamellae.