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

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Hemerodromia namtokhinpoon

sp. nov.

Hemerodromia namtokhinpoon  sp. nov.

( Figs 53, 54View FIGURES 53 – 54, 90View FIGURES 82 – 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 ~ 2.5–2.8 X long as wide, a few minute outstanding setulae subapically; stylus shorter, ~ 0.5 X 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. C 1 ~1.0– 1.1 X longer than distance between C 1 and C 2, all setulae minute excepting a few slightly longer dorsals on distal 0.2. F 1 ~ 1.2 X long as C 1, ~ 6 X 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. T 1 ~ 0.7–0.8 X long as F 1, 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 R 2 + 3, R 4 + 5 and cell bm+dm but pale yellowish near base. Marginal setulae pale. R 2 + 3 almost linear, joining C ~ 0.7–0.8 X distance between end of R 1 and R 4; length of C between ends of R 2 + 3 and R 4 ~ 1 X long as R 4; R 4 slightly S-shaped, angle with R 5 at extreme base ~ 80 °, becoming ~ 70–80 ° thereafter, joining C at ~ 80 °. R 5 ~ 2.2–2.5 X long as R 4, almost linear; R 4 + 5 fork distal to M 1 + 2 fork by ~ 0.8 –1.0X length of R 4. M 1 almost linear beyond base, convergent distally with R 5; cell bm+dm short, ending at tip of R 1. 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. 53View FIGURES 53 – 54); 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. 54View FIGURES 53 – 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 F 1 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. 90View FIGURES 82 – 90) in Loei Province, northeast Thailand. (Suan Hom, conductivity 414 µS/cm 2, pH 8.08; Suan Sawan conductivity 418 µS/cm 2, pH 7.84). The two specimens from Tat Mueng were captured from a basic (pH 7.21), but less mineralised stream (conductivity 77 µS/cm 2), 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.


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