Tachypeza vietnamensis Grootaert & Shamshev, 2009, sp. nov.

Tachypeza vietnamensis sp. nov.

(Figs. 7–9)

Diagnosis. Recognized by shining anepisternum and katepisternum, palpus with short pale setae, 1 notopleural seta; in male fore leg with complicated color pattern including anterior black patch on fore coxa, maculate fore femur and tibia.

Description. Male. Body 3.0 mm, wing 2.9 mm. Head black. Eyes extending beyond ocellar tubercle. Frons densely pollinose, rather narrow and only slightly widened toward ocellar tubercle. Ocellars minute. Occiput entirely pollinose; with 2 pairs of strong black setae on upper part and numerous pale hair-like setae near neck and on lower part. Antenna with postpedicel yellow, scape and pedicel brownish yellow, style brownish; postpedicel short, elongate oval; stylus subapical, very long, short pubescent. Proboscis brownish, rather long. Palpus unmodified, short, elongate oval, yellow, with several pale short setae.

Thorax black brown, largely densely tomentose, anepisternum (= mesopleuron) and katepisternum (= sternopleuron) shining, anepimeron (= pteropleuron), meron (= hypopleuron) and laterotergite (= metapleuron) finely tomentose, subshining. Postpronotal lobe large, with some minute setulae. Mesonotum with 1 short strong notopleural and 2 similar wide apart scutellar setae; acrostichals and dorsocentrals minute, scattered; the former arranged in 2 broad rows, lacking on prescutellar depression, the latter uniserial, uniform including prescutellar pair; additionally, some minute setulae present on notopleural depression.

Legs with complicated color pattern; fore coxa yellow but with subapical contrastingly black patch anteriorly, mid coxa yellowish brown, hind coxa yellow; fore trochanter blackish ventrally, mid and hind trochanters yellow; fore femur largely yellow, maculate, with rather small black subapical patch posteriorly, similar but larger patch anteriorly and trident-like patch on middle part anteriorly; mid femur with indistinct pattern, brownish yellow apically, otherwise yellowish; hind femur almost entirely brownish, paler on middle part and narrowly yellow basally; fore tibia maculate, with anterior and posterior brown stripes interrupted on middle part by yellow space; mid tibia largely brownish, yellowish to brownish yellow on middle part dorsally and ventrally; hind tibia largely pale yellow, contrastingly black on about apical 1/6; fore basitarsus brown ventrally (except subapical part), tarsomere 5 entirely brown, otherwise fore tarsomeres yellowish; mid basitarsus almost entirely yellow (except for narrow brownish subapical space), remaining hind tarsomeres brownish, hind tarsi with similar pattern but paler on yellow part and darker on brown part. Fore coxa with unmodified setation, clothed in scattered pale thin setae anteriorly. Mid coxa with short pale seta on outer face. Mid and hind trochanters with short setae. Fore femur strongly thickened, with minute anteroventral and posteroventral setulae more numerous basally, bearing row of several setulae (2 longer) on middle part anteriorly. Fore tibia spindle-shaped, almost lacking setulae on dorsal face. Fore basitarsus with rows of ventral spinules. Mid femur slender, with regular rows of minute anteroventral and longer and stronger posteroventral setulae, near extreme base armed with tubercle bearing 2 brownish yellow spines. Mid tibia almost lacking setulae on dorsal face, with rather large subapical ventral excision, bearing ventral spinules and 1 long black curved subapical posteroventral seta. Mid tarsus unmodified. Hind legs long, slender, with inconspicuous setation; hind tibia slightly thickened and with denser setulae on black subapical part.

Wing normally developed, rounded at apex, more or less uniformly finely brownish infuscate, somewhat paler basally and darker along veins R2+3 and R4+5. Basal costal seta inconspicuous. Vein R1 meeting costa near wing midway. Proximal section of vein R4+5 slightly longer than Rs. Vein R2+3 slightly sinuate. Veins R4+5 and M1+2 parallel toward wing-apex but both evenly bowed. Crossveins r-m and bm-cu separated. Cells br and bm extending to wing midway. Squama pale colored and fringed. Halter pale yellow.

Abdomen with tergites 1–3 paler, brownish to yellowish brown, remaining tergites black, matt, with scattered dark minute setulae; sternites 1–3 brownish yellow, sternites 4–5 brown, remaining sternites black, with scattered minute setulae longer on pregenital segments. Segment 8 asymmetrical, with strongly sclerotised, entirely fused sclerites, tergite 8 narrowed and lacking setation medially.

Terminalia (Figs. 7–9) rather large, brown. Right cercus digitiform, with short unmodified setae. Left cercus short, broad, somewhat produced on left margin and with short apical projection on upper margin, covered with numerous spinule-like setulae on produced part subapically and with several unmodified moderately long setae on upper margin. Right epandrial lamella with scattered, short, unmodified setae, lacking ventral projection. Right surstylus differentiated from epandrium, of complicated structure as in Figure 7, with subapical part weakly sclerotised, sculptured and bent inwards, bearing scattered unmodified setulae. Left epandrial lamella rather small, with several very long setae. Left surstylus completely differentiated from epandrium, subtriangular, with several long marginal and subapical setae. Hypandrium strongly humped, bare.

Female. Primarily differing from male in color of fore legs; fore coxa and fore trochanter entirely yellow; fore femur with indistinct color pattern, almost entirely reddish yellow, brownish yellow on apical part posteriorly; fore basitarsus entirely yellowish; mid femur and tibia unmodified; cercus brown, long, slender.

Material examined. Holotype male, VIET NAM: Lao Cai Prov., Sa Pa, Sin Chai, c. 1900 m, 11.09– 21.10.1999, Malaise trap, leg. R. de Vries [Naturalis].

Paratype: 1 female [RBINS], same data as in holotype.

Derivatio nominis. The specific epithet refers to the state of the origin of the new species, Viet Nam.

Distribution. Viet Nam.

Remarks. Comparing with Palaearctic species of Tachypeza the new species resembles T. heeri Zetterstedt and T. fennica Tuomikoski (Chvála, 1975). Besides distinct differences in the male terminalia, T. vietnamensis sp. nov. can be readily distinguished from these species by broadly tomentose mesothoracic pleuron and details of color and armature of the male fore legs. More problematic may be distinguishing the new species from T. nigra Yang & Yang described from a single female from Hubei Province of China (Yang & Yang 1997). According to the original description in T. nigra, the fore tibiae are dark brown (except base) and hind femora are black (except base).