Tachydromia annamensis, Grootaert, Patrick & Shamshev, Igor, 2009

Grootaert, Patrick & Shamshev, Igor, 2009, First records of Tachydromia Meigen and Tachypeza Meigen (Diptera: Hybotidae) from Viet Nam, with descriptions of four new species, Zootaxa 2249, pp. 33-43 : 36-38

Tachydromia annamensis sp. nov.

( Figs. 4–6 )

Diagnosis. Palpus yellow. Legs with complicated color pattern; fore femur posteriorly black. Wing almost entirely finely brownish infuscate, paler near base and hyaline on tip, dark brown along anterior margin. Halter with brown knob, pale stem. Male: fore tibia unmodified.

Description. Male. Body 3.5-3.8 mm, wing 2.4-2.5 mm. Head black in ground-color. Eyes extending beyond ocellar tubercle. Frons subshining, slightly widened toward ocellar tubercle, above antennae nearly 1.5 times as broad as anterior ocellus. Ocellars minute. Occiput largely finely pollinose, narrowly shining in upper part beyond eyes; with 2 short strong black setae in upper part, 2 similar setae on middle part laterally and numerous pale hair-like setae near neck and on lower part. All antennal segments brownish; postpedicel short, elongate oval; stylus at least four times as long as pedicel and postpedicel together, brownish, short pubescent. Proboscis black, yellow proximally. Palpus unmodified, short, elongate oval, yellow, with 1 black, longer than palpus and 1 subequal but thinner brown subapical setae and 4–5 black setae basally, dorsal one as long as palpus.

Thorax black in ground-color, largely subshining; prominent setae black; prothoracic sclerites (except postpronotal lobe) silvery pollinose. Postpronotal lobe large, lacking conspicuous setae. Mesonotum with 2 notopleural (posterior one longer) and 2 scutellar setae; Acrostichals and dorsocentrals minute, the former multiseriate anteriorly, lacking on prescutellar depression, the latter uniserial.

Legs long, with complicated color pattern; fore coxa entirely black, mid coxa almost entirely brownish, hind coxa entirely yellow; all trochanters yellow; fore femur brownish-black dorsally, anteriorly and posteriorly, ventrally yellowish brown; mid femur black, but ventrally brownish; hind femur pale yellow on basal 1/5, otherwise completely black; fore and mid tibiae brownish, hind tibia yellowish on basal 1/3–1/2, otherwise black; fore and mid tarsus yellowish brown, apical two tarsomeres brown; hind tarsus almost completely brownish, except for the basal half of hind basitarsus that is paler brown. Coxae anteriorly near tip with black bristles, further mostly with pale hair-like setae; hind coxa without strong black curved seta anteriorly; pale hair-like setae present between mid and hind coxae. Fore femur strongly thickened, mostly with minute anteroventral and posteroventral setulae, bearing 4–5 stronger spinule-like anteroventral setulae near middle. Fore tibia slightly swollen, with inconspicuous setation. Mid femur slender, with anteroventral and posteroventral very short (the latter longer) hair-like setae becoming somewhat longer toward base of femur, a long brown ventral seta near base. Mid tibia slender, lacking prominent bristles with some ventral spinule-like setulae. Hind femur slender, with rows of short strong anteroventral and posteroventral setae becoming shorter and thinner basally. Hind tibia slender, lacking prominent bristles, with narrow pointed posterior apical comb. Tarsi of all legs unmodified.

Wing normally developed, rounded at apex, with typical venation for genus; largely finely brownish infuscate, paler near base and hyaline on tip, dark brown along anterior margin. One short basal costal seta present. Vein R1 meeting costa beyond wing midway. Proximal section of vein R4+5 considerably longer than Rs. Vein R2+3 straight. Veins R4+5 and M1+2 parallel toward wing-apex. Crossveins r-m and bm-cu separated. Cells br and bm extending to wing midway. Halter with pale stem and black knob.

Abdomen with segment 1 pale, otherwise brown, covered mostly with scattered, short, black setulae; segments 7 and 8 with moderately long setae.

Terminalia ( Figs. 4–6 ) large, dark brown, elongate oval. Right cercus long, tapered apically, covered with numerous unmodified setae of different length, bearing a number of long apical setae. Left cercus about halflength of right cercus, pointed apically, covered with scattered short setae. Right epandrial lamella subtriangular (viewed laterally), with large rounded ventral process in subapical part, bearing numerous setae of different lengths. Right surstylus long, narrow, bent inward, with several unmodified setae of different length apically and on inner side. Left epandrial lamella subtriangular, bearing several unmodified setae of different lengths. Left surstylus completely differentiated from epandrium, short, subrectangular, with 1 very long subapical seta, several strong flattened setae on upper margin and some short setae apically.

Female. Body: 3.7–3.8mm, wing: 2.4–2.5mm. Fore femur lacking stronger anteroventral spinules near middle. Mid and hind femora lacking prominent anteroventral and posteroventral setae. Otherwise as in male. Cercus brownish, rather short.

Material examined: Holotype male, VIET NAM: Dak Lak Prov., Chuo Yang Sin NP c. 50 km S. Buôn Mê Thuot, Krong K’Mar 590–840 m, Mal. 13–23, 22– 26.10.2005, rain forest nr river. Leg. C. van Achterberg & R. de Vries (Naturalis). Paratypes: 3 males, 4 females, same provenance as holotype.

Derivatio nominis. The specific epithet refers to the Annam Highlands in which the species was found.

Distribution. Viet Nam.

Remarks. The new species is very closely related to T. phanensis Shamshev & Grootaert, 2008 . However it is much larger. Additional differences are mainly found in coloration, they are minor in genitalia structure. Postpedicel is brownish and has the same color as the scape and pedicel. Postpedicel in T. phanensis is much paler than the basal segments. Palpus has long black basal setae as long as palpus. The basal setae in T. phanensis are shorter and paler. Fore coxae have mainly a black setation, being pale in T. phanensis . Hind coxae have a black anterior bristle in T. phanensis , absent in T. annamensis sp. nov. Fore femur is posteriorly black, in T. phanensis , basal half of fore femur is yellow posteriorly. Fore femur anteriorly near middle with about four spine-like bristles, these bristles are much weaker in T. phanensis . Hind tibia is yellow on basal half and black on apical half. This character is the same in T. phanensis although it was not mentioned clearly in the original description. Re-examination of the male genitalia in T. phanensis also showed that the black bristles bordering the left surstylus are quite comparable to T. annamensis sp. nov. The latter species however lacks a very long apical bristle on the tip of the right cercus, replaces with a brush of long bristles. There were probably a few more bristles on the right cercus in T. phanensis that are lost as indicated by the insertions. The main differences of T. annamensis sp. nov. from other species of the Oriental Tachydromia can be found in the key.

Figures

FIGURES 4 – 6. Tachydromia annamensis sp. nov. 4. right epandrial lamella, lateral view. 5. hypopygium, dorsal view. 6. left epandrial lamella, lateral view.