Hemerodromia oriens, Plant, Adrian R., 2015

Plant, Adrian R., 2015, Diversity of Hemerodromia Meigen, 1822 (Diptera: Empididae) in Thailand, the tip of a tropical iceberg?, Zootaxa 4039 (1), pp. 1-56 : 38-39

Hemerodromia oriens sp. nov.

( Figs 58, 59 , 92 )

Diagnosis. A species with thorax black, legs and antenna yellowish. Male terminalia with cercus very narrow in profile but in dorsal view very broad proximally. Epandrium rather narrow, apically pointed. Surstylus extending beyond tip of epandrium, small, narrow but apically spatulate, incurved distally.

Description. Male: Body length 2.3 mm; wing length 2.0 mm. Head. Black, dusted grey, strongest on upper occiput and vertex. Antenna entirely pale yellowish white. Mouthparts yellowish white. One pair reclinate ocl; 1–2 pairs small vtl distinguishable from smaller fine hairs on vertex and upper occiput; postocular and lower occipital setulae minute. Antenna with postpedicel ~2.5X long as wide, stylus rather shorter; scape with fine dorsal seta. Thorax. Black, dusted greyish; scutellum somewhat paler brownish black; sometimes proepisternum and postpronotal area laterally somewhat paler. All setae yellowish; minute apart from one npl; sct absent but scutellum with a pair of very small erect setulae on disc.

Legs. Pale yellowish white with apical tarsomere on all legs slightly darker. C1 ~ 1.2–1.3X longer than distance between C1 and C2; C1, C2 and C3 with all setulae minute. F1 ~ 1.1X long as C1, ~ 4– 5 X long as wide, not at all constricted 0.3 from base; femoral formula ~ 8– 10 /19–21/18–23+0–1/10–20, denticles black, rows converging apically; spines yellow, short, fine much shorter than limb is deep longest basally, basal spine of pv and av row longest, pv spines 1–2-serial with inner row slightly stronger. T1 ~ 0.6–0.7X long as F1, evenly curved, ventral face shallowly concave; with 2 rows of ~17–18 sharply pointed spinose setae ventrally; ventroapical spur hardly developed; a strong ventroapical erect black spinose seta present. Mid and hind legs slender with only small setulae. Wing. Membrane conspicuously and uniformly darkened with black microtrichia but hyaline basally. Veins blackish but whitish near base. Marginal setulae greyish. R2+3 linear, joining C ~ 0.6X distance between end of R1 and R4; length of C between ends of R2+3 and R4 ~1.7–1.8X long as R4. R4 almost linear, only slightly Sshaped; R5 ~2.2X long as R4; R4+5 fork distal to M1+2 fork by ~ 1.5X length of R4; R5 and M1 almost linear, convergent distally; cell bm+dm short, ending at level of R1. Halter with knob variably whitish to blackish, stem paler. Abdomen. Tergites blackish but tergite 1 usually pale with very narrow transverse black fascia at middle; sternites paler (especially on segments 1 and 2), variable whitish to brown, often with anterior margins darker; all setulae small, becoming longer on distal segments. Terminalia. Brownish with admixed pale and dark setae. Cercus very elongate in lateral view ( Fig. 58 ), extending beyond tip of epandrium, slightly narrowed subapically, somewhat spatulate apically; in dorsal view very broad on proximal 0.5 with distal lobe narrower and slightly incurved ( Fig. 59 ). Epandrium rather narrow, apically pointed ( Fig. 58 ). Surstylus present, extending beyond tip of epandrium, small, narrow but apically spatulate, incurved distally. Hypandrium narrow, strongly upcurved distally. A broad elongate inner process (probably representing posterior process of subepandrial sclerite) curved around tip of hypandrium distally; weakly sclerotized, especially distally; apex membranous bearing 5–6 minute black points. Female: Similar to male basal spines on F1 rather stronger; abdomen with sternites whitish but with sternites 7 entirely and usually sternites 1 along margins darker.

Type material. HOLOTYPE ♂, THAILAND: Mukdahan Province, Phu Ha Kam, stream in dry evergreen forest, 16.4196°N, 104.4100°E, 24.xi.2009, netted, A.R. Plant ( QSBG). PARATYPES: 5♂, 3♀, same data as holotype; 1♂, 2♀, 26.xi.2009; 3♀, 4♀, Phu Ha Kud, stream in deciduous / dry evergreen forest, 16.4772°N, 104.4067°E, 25.xi.2009, netted, A.R. Plant ( QSBG & NMWC).

Etymology. The specific epithet oriens (Latin) meaning eastern, reflects the only known occurrence of this species in the east of Thailand. It is used as a noun in apposition.

Remarks. Hemerodromia oriens sp. nov. is similar to many other Oriental Hemerodromia having a black thorax, pale legs and M1+2 fork present. The male cercus is narrow in profile but very broad, almost quadrate basally in dorsal view ( Fig. 58 ), quite different from H. yunnanensis Yang & Yang, 1988 , H. fusca Yang & Yang, 1986 and H. phahompokensis sp. nov. with which it might otherwise be confused. Hemerodromia oriens sp. nov. is only known from small shaded streams in lowland deciduous and dry evergreen forests in the eastern province of Mukdahan ( Fig. 92 ). Adults have been captured during November at the start of the cool dry season.

Figures

FIGURES 58 – 59. Male terminalia of Hemerodromia oriens sp. nov. 58, lateral view of terminalia; 59, dorsal view of cerci. Abbreviations: cer = cerci, epa = epandrium, hyp = hypandrium, ph = phallus.

FIGURES 91 – 98. Distribution of Hemerodromia spp. in Thailand at a resolution of 0.25 ° of latitude and longitude with symbols scaled to 0.5 °. 91, H. ocellata sp. nov.; 92, H. oriens sp. nov.; 93, H. phahompokensis sp. nov.; 94, H. songsee sp. nov.; 95, H. systoechon sp. nov.; 96, H. yunnanensis Yang & Yang; 97, H. zetalutea sp. nov.; 98, Species richness of Hemerodromia spp. in Thailand at a resolution of 1 ° with symbols plotted at same resolution.