Hybos yungyak, PLANT, 2013

PLANT, ADRIAN R., 2013, The genus Hybos Meigen (Diptera: Empidoidea: Hybotidae) in Thailand, Zootaxa 3690 (1), pp. 1-98 : 80-82

Hybos yungyak sp. nov.

( Figs 214–218 , 281 )

Type material. HOLOTYPE ♂: THAILAND, Chiang Mai Province, Doi Phahompok National Park , Doi Phaluang , 20°1.06'N, 99°9.581'E, 1449 m, 21–28.iii.2008, Malaise trap, P.Wongchai, [ T6284 ] ( QSBG). PARATYPES: 19♂, 17♀, same data as holotype, 14–21.iii.2008, 21–28.iii.2008, 21–28.iii.2008. 28.iii.-7.iv.2008, 28.iv.-7.v.2008 ; 21♂, 42♀ same data as holotype, Kiewlom 1/montane forest, 20°3.549'N, 99°8.552'E, 2174 m, 7– 14.iii.2008, 14–21.iii.2008, 21–28.iii.2008, 28.iii.-7.iv.2008, 14–21.iv.2008, 21–28.iv.2008, 28.iv.-7.v.2008, 14– 21.v.2008 ; 3♂. 3♀, Mae Fang Hotspring , 19°57.961'N, 99°9.355'E, 569 m, 25–28.iv.2008: 10♂, Chiang Mai Province, Huai Nam Dang National Park , guest house, 19°18.803'N, 98°36.395'E, 31.i.-7.ii.2008, 7–13.ii.2008, 13–20.ii.2008, 29.ii.-7.iii.2008, 7–13.iii.2008 ; 11♂, 4♀, Helipad , 19°18.33'N, 98°36.289'E, 7–13.ii.2008, 20– 27.ii.2008, 29.ii.-7.iii.2008, 7–13.iii.2008, 13–20.iii.2008, 1–14.iv.2008, 14–21.iv.2008 ; 11♂, 12♀, Thung Buatong View Point , 19°17.56'N, 98°36.029'E, 7–13.ii.2008, 29.ii.-7.iii.2008, 7–13.iii.2008, 13–20.iii.2008, 20–27.iii.2008, 31.iii.-7.iv.2008, 7–14.iv.2008, 14–21.iv.2008, 21–28.iv.2008 ; 1♂, 3♀, Visitor centre, 19°18.803'N, 98°36.408'E, 31.iii.-7.iv.2008, 21–28.iv.2008: 7♂, 19♀, Chiang Mai Province, Doi Inthanon National Park, Checkpoint 2, 18°31.554'N, 98°29.94'E, 1700 m, 15–22.iv.2007, 1–8.v.2007, 8–15.v.2007 ; 1♂, 14♀, Kew Maepan Trail , 18°33.162'N, 98°28.81'E, 2200 m, 16–23.iii.2007, 23.iii.-1.v.2007, 15–22.iv.2007, 22–29.iv.2007, 29.iv.-6.v.2007, 1–8.v.2007, 8–15.v.2007 ( NMWC, QSBG).

Etymology. From the Thai yung yak = a spiny or difficult person, in fanciful reference to the fiercely spinose hind femur of males of this species.

Diagnosis. A rather large species with thorax black (although scutellum often yellow) and legs variably deep orange to dirty brownish yellow with distal tarsal segments dusky; anterior and mid coxae and all trochanters blackish. The hind femur is strongly spinose ventrally in males and the mid tibia has only 1 very strong bristle dorsally. The antennal stylus is micropilose to subplumose and the abdomen has tergite 1 laterally and sternite 1 yellow.

Description. Male: length 4.2–5.5 mm. Head subshining black; face distinctly yellowish below. Postocular setae black, longish hairs on lower occiput mostly dark. Antenna black, postpedicel ovate in lateral view, ~2.0– 2.5X long as wide; stylus ~6X long as postpedicel, black, micropilose to subplumose with lateral hairs hardly longer than stylus is deep, bare and narrower on distal 0.1–0.15. Mouthparts brownish black, palpus very narrow, with distinct fine seta near tip and several smaller ones along length ventrally. Thorax with scutum ground colour black, often yellowish about postalar callus and sometime narrowly paler on lateral margin of postpronotal lobe, rather densely greyish dusted, with faint indications of broad median darker stripe and rather shining patch behind postpronotal lobe; scutellum variably black to yellow; pleura black to deep reddish black, strongly dusted greyish. Scutum with acr 4-serial, dc uniserial; posterior dc and acr in front of prescutellar depression strong; 2 npl, 1 pa and 2 sct strong. Legs variably deep orange to dirty brownish yellow with distal tarsal segments dusky; anterior and mid coxae and all trochanters blackish; posterior coxa blackish at least anteroapically (sometimes entirely suffused blackish); F 3 usually with dark streak anteriorly on proximal 0.8. Coxae with pale hairs, yellowish behind C 3, somewhat brownish on C 2 and C 1 anteriorly, legs otherwise with stronger setae black. F 1 with ventral hairs very short, erect, more or less absent on distal 0.5. F 2 slightly distorted, weakly concave in front about 0.3 from base where ad fine hairs as long as limb is deep, ventral fringe very short. F 3 moderately inflated, widest 0.5–0.7 from base; viewed laterally lower margin almost linear, upper margin convex; ventral spines comprising 25–30 long bristles (mostly as long or longer than limb is deep) arranged in 2 rows near base becoming ~3-serial at middle and uniserial apically where shorter; pv fringe of 9–10 strong black evenly spaced bristles on distal 0.8; 4 distinct somewhat curved proclinate bristles anteriorly on distal 0.6. T 1 with 1 distinct bristle dorsally at 0.5 from base; 1 long, somewhat curved ad distinct in apical circlet. T 2 with strong bristles 0.8X long as limb dorsally at ~0.3 from base and ventrally at 0.4–0.5; 1 shorter posterior subapical at ~0.9; apical circlet strong with 1 av ~0.7X long as MT2. T 3 slightly inflated distally, 1 distinct bristle dorsally at 0.4–0.5 (sometimes also at 0.6), 3 distinct apical setae. MT 1 and MT 2 with distinct ventrobasal bristle. MT 1 with fine hairs ventrally becoming shorter distally. MT 2 and MT 3 with slightly stronger somewhat spinose setae admixed with finer hairs ventrally. Wing membrane tinged brown, veins brownish; stigma distinct, greyish, reaching costa at ~0.7 distance between end of R 1 and R 2+3. Squamae with pale hairs. Halter white. Abdomen subshining brownish black with tergite 1 laterally and sternite 1 yellow, dusted greyish. Tergites with long yellowish bristles on posterior margin, becoming shorter on distal segments; sternites with somewhat shorter hairs on posterior margin, hardly shorter on distal segments. Terminalia ( Figs 214–217 ) globoid, black with black setae; left epandrial lamella ( Fig. 215 ) with small protuberant process subapically on dorsum; long strong bristles along ventral margin; right epandrial lamella with strong bristles apically; left surstylus ( Fig. 215 ) trilobed, central lobe rather narrow and somewhat curved; right surstylus ( Fig. 217 ) trilobed, dorsal lobe broad, ovate, larger than other lobes. Hypandrium ( Fig. 216 ) narrowed apically, with tip blunt, curving inwardly; short digitiform process subapically. Female. Similar to male but F 3 rather more slender, only 15–22 bristles ventrally which are biserial near middle but uniserial about base and tip; pv fringe weaker, comprising long fine yellowish hairs (often with a few darker black bristles admixed). Abdomen with shorter setae on posterior margin of tergites. Terminalia ( Fig. 218 ) black, setae yellowish brown to black; sternite 8 slightly protuberant, narrowed medially in ventral view, with strong rather erect bristles; tergite 8 not encircling abdomen, with long marginal bristles; sternite 10 small, weakly sclerotized.

Comment. The degree of darkening of the essentially dark yellow ground colour of the legs of H. yungyak sp. nov. varies and in some individuals the hind femur and all coxae can be very dark. The form of the male hypandrium with a short subapical digitiform process suggests affinities with the H. zhejiangensis -group of species, some of which (especially H. zhejiangensis Yang & Yang, 1995 , H. mangraii sp. nov., H. ruyuanensis Yang, Merz & Grootaert, 2006 and H. guizhouensis Yang & Yang, 1988 ) also show similarities in the morphology of the surstyli. Hybos yungyak sp. nov. has been found only on the Daen Lao and Thanon Thongchai mountains in northern Thailand ( Fig. 281 ) and is predominantly a species of montane hill evergreen forests. Adults are active from early January to May coincident with the cold dry season and start of the wet season.

Figures

FIGURES 214–218. Hybos yungyak sp. nov. 214. ♂ terminalia, dorsal view. 215. left epandrial lamella and left surstylus, lateral view. 216. hypandrium, ventral view. 217.. right surstylus, lateral view. 218. ♀ terminalia, ventral view. S8= sternite 8, S10 = sternite 10.

FIGURES 278–282. Distribution of Hybos spp. in Thailand plotted at a resolution of 1° of latitude and longitude. 278. H. thepkaisoni sp.n. 279. H. tilokarati sp. nov. 280. H. xishuangbannaensis Yang & Yang. 281. H. yungyak sp. nov. 282. H. zhejiangensis Yang & Yang.