Hemerodromia namtokhinpoon, 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 : 35-36

Hemerodromia namtokhinpoon sp. nov.

( Figs 53, 54 , 90 )

Diagnosis. A species with thorax entirely yellow with only sutures in front of root of halter and between prothoracic ‘collar’ and front of scutum blackish, Sct present. Cell bm+dm short. Wing veins and membrane conspicuously darkened proximally about level of cell bm+dm. Epandrium very elongate with very strong apical bristle.

Description. Male: Body length 1.75–2.2 mm; wing length 1.9 mm. Head. Black, dusted greyish, frons paler; antenna and mouthparts pale whitish yellow, all setae pale; one pair reclinate ocl; postocular setae very small, becoming somewhat longer below, merging above with 2–3 pairs small vtl and a few fine hairs on vertex; frontal setulae apparently absent. Antenna with postpedicel ~2.5–2.8X long as wide, a few minute outstanding setulae subapically; stylus shorter, ~0.5X long as postpedicel; scape with distinct fine dorsal seta. Thorax. Dusted greyish. Ground colour clear yellow including mediotergite and prothoracic ‘collar’; only sutures in front of root of halter and between anterior margin of scutum and prothoracic ‘collar’ darkened. All setae yellowish; minute apart from a pair of distinct sct and one smaller npl. Legs. Pale yellow. C1 ~1.0–1.1X longer than distance between C1 and C2, all setulae minute excepting a few slightly longer dorsals on distal 0.2. F1 ~ 1.2X long as C1, ~ 6X long as wide, evenly inflated, not constricted on proximal 0.3; femoral formula ~ 7– 8 /17–19/19/8–9, denticles black, rows converging apically; spines yellow, pv and av rows similarly very short and hair-like, becoming somewhat longer proximally. T1 ~ 0.7–0.8X long as F1, evenly curved, ventral face shallowly concave; with 2 rows of ~ 17 similarly sized sharply pointed spinose setae ventrally; ventroapical spur extremely small; a distinct ventroapical erect black spinose present. Mid and hind legs slender with only small pale setulae. Wing. Membrane darkened by rather even covering of yellowish brown microtrichia, darker still in band across wing at level of cell bm+dm but hyaline basally. Veins yellowish grey, distinctly blackish about base of R2+3, R4+5 and cell bm+dm but pale yellowish near base. Marginal setulae pale. R2+3 almost linear, joining C ~ 0.7–0.8X distance between end of R1 and R4; length of C between ends of R2+3 and R4 ~ 1X long as R4; R4 slightly S-shaped, angle with R5 at extreme base ~ 80°, becoming ~70–80° thereafter, joining C at ~ 80°. R5 ~ 2.2–2.5X long as R4, almost linear; R4+5 fork distal to M1+2 fork by ~ 0.8–1.0X length of R4. M1 almost linear beyond base, convergent distally with R5; cell bm+dm short, ending at tip of R1. Halter yellowish white. Squama with margin blackish. Abdomen. Yellow with tergites 2–6 brown or blackish with 2, 5 and 6 variably yellowish anterolaterally; all setae yellow, short but longer on distal segments, especially sternites 6 and 7. Terminalia. Black, small. Cercus of complex structure ( Fig. 53 ); about as long as epandrium; apically with two inwardly curving blunt spinose rather shallowly crenate lobes; broad proximally in dorsal view with a ciliation of short, stout, close-set posteriorly directed setae on inner face medially ( Fig. 54 ). Narrow process with spatulate tip emerging below ventral margin of cercus (probably posterior process of subepandrial sclerite). Epandrium very narrow, elongate with strong incurved apical bristle and several smaller bristles on outer face. Hypandrium subovate, apparently lacking distinct setae. Female: Similar to male but F1 with spines rather longer (especially proximal two of both av and pv rows). Abdomen with setae very small, inconspicuous.

Type material. HOLOTYPE ♂, THAILAND: Loei Province, Wong Huy [Nong Hin], Suan Hom w/f (tufa stream), 579 m, 17.0415°N, 101.757°E, 29.xi.2013, netted, A.R. Plant ( QSBG). PARATYPES: 1♂, 4♀, same data as holotype; 2♂, 5♀, 22.xi.2013; 10 ♀ Nong Hin, Suan Sawan (tufa stream), 676 m, 17.0596°N, 101.7421°E, 26.xi.2013, netted, A.R. Plant; 2♀, Na Haeo, Phu Suan Sai NP, Tat Mueng, by w/f, 560 m, 17.561°N, 100.991°E, netted, A.R. Plant ( QSBG & NMWC).

Additional material. 5♂, 5♀ (teneral), same data as holotype, 22.xi.2013; 2♂, 3♀ (teneral), Nong Hin, Suan Sawan (tufa stream), 676 m, 17.0596°N, 101.7421°E, 26.xi.2013, netted, A.R. Plant; 2♀ (teneral), Phu Suan Sai NP, Tat Mueng, by w/f, 560 m, 17.561°N, 100.991°E, netted, A.R. Plant ( QSBG & NMWC).

Etymology. The specific epithet is a contraction of the Thai nam tok hin poon meaning tufa (literally ‘limestone waterfall’) in reference to the species’ clear preference for tufa habitats. It is used as a noun in apposition.

Remarks. This species may be distinguished from other predominantly yellow species of Hemerodromia occurring in Thailand by its complex crenate cercus and elongate epandrium which bears a very strong apical bristle. All but one of the 39 specimens of H. namtokhinpoon sp. nov. examined were taken in close proximity to basic and mineral rich tufa streams ( Fig. 90 ) in Loei Province, northeast Thailand. (Suan Hom, conductivity 414 µS/cm2, pH 8.08; Suan Sawan conductivity 418 µS/cm2, pH 7.84). The two specimens from Tat Mueng were captured from a basic (pH 7.21), but less mineralised stream (conductivity 77 µS/cm2), lacking in tufa formations. The tufa streams inhabited by H. namtokhinpoon sp. nov. flow through predominantly dry forest biotopes at low elevation (560–627 m). Adults have been captured in late November during the cool dry season.

Figures

FIGURES 53 – 54. Male terminalia of Hemerodromia namtokhinpoon sp. nov. 53, lateral view of terminalia; 54, dorsal view of cerci. Abbreviations: cer = cerci, epa = epandrium, hyp = hypandrium.

FIGURES 82 – 90. Distribution of Hemerodromia spp. in Thailand at a resolution of 0.25 ° and symbols sized to 0.5 ° of latitude and longitude. 82, H. demissa sp. nov.; 83, H. epsilutea sp. nov.; 84, H. etalutea sp. nov.; 85, H. flaviventris Yang & Yang; 86, H. furcata Grootaert, Yang & Saigusa; 87; H. fusca Yang & Yang; 88, H. gammalutea sp. nov.; 89, H. isochita sp. nov.; 90, H. namtokhinpoon sp. nov.