Hemerodromia anomala, 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 : 13-14

Hemerodromia anomala sp. nov.

(Figs 3–5, 16, 17, 76)

Diagnosis. A blackish species characterised by having a quadrate head with upper occiput shallowly concave, antenna with stylus thickened and thorax distinctly quadrate anteriorly in lateral view. The wing has R2+3 terminating in R4 rather than in C and a strong black stigma about the length of R4.

Description. Male: Body length 2.5–2.7 mm; wing length 1.6–1.8 mm. Head. Elongate quadrate, angle between upper occiput and vertex a smoothed right angle in lateral view; upper occiput shallowly concave medially; lower occiput slightly bulging laterally (Fig. 5). Black, dusted greyish. Antenna and mouthparts pale yellowish white. One pair reclinate ocl; 3 pairs distinct vtl, rather stronger than ocl, positioned in linear series parallel with upper eye margin, clearly distinguishable from smaller minute hairs on vertex and occiput and from postocular setulae. Antenna with postpedicel ~1.8X long as wide, subovate, narrowing distally (hardly conical); stylus thickened, ~0.5X length of postpedicel (Fig. 5), apical mechanoreceptor apparently absent; scape with inconspicuous fine dorsal seta. Thorax. Distinctly quadrate anteriorly; anterior margin of scutum almost vertical in lateral view (Fig. 5) making distinct but smooth right angle with disc (not gradually curving). Ground colour reddish black or reddish brown. All setae pale; minute apart from one small and one minute npl; scutellum with a pair of small fine hairs and several smaller setulae on disc. Legs. Ground colour whitish with apical tarsomere darker, sometimes blackish. C1 ~1.1X long as distance between C1 and C2; all coxae with only minute setulae but with a few longer hairs dorsally and near tip of C1. F1 ~1.1X long as C1, moderately inflated ~ 5X long as wide, not constricted on proximal 0.3; femoral formula ~ 6–7/17/16 /6–7; denticles black, rows converging apically; spines whitish, rather evenly sized, not becoming distinctly longer proximally. T1 ~ 0.8X long as F1, sublinear, ventral face only slightly concave; with one row of ~15–16 rather weak sharply pointed spinose setae ventrally; a distinct ventroapical erect black or yellowish spinose seta present; ventroapical spur very weakly developed. Mid and hind legs slender with only small setulae. Wing. Membrane distinctly darkened with greyish microtrichia, pale near extreme base; a strong black irregularly trapezoid stigma around R4 (Figs. 3, 4). Veins greyish but C yellowish before junction with R2+3 and R2+3 yellowish distally. Marginal setulae pale grey. R2+3 linear, joining R4. R4 weakly S-shaped; slightly recurrent, outer angle with R5 at extreme base ~ 90–95°; R5 ~2.0, –2.5X long as R4; R4+5 fork distal to M1+2 fork by ~ 1X length of R4; R5 and M1 slightly convergent, becoming faintly divergent at wing margin (Fig. 4). Cell bm+dm short, ending at or slightly beyond level of R1. Halter whitish. Abdomen. Ground colour blackish or brownish, somewhat paler on vent; all setulae inconspicuous, mostly pale, very short dorsally, somewhat longer ventrally. Terminalia. Cercus and epandrium black with dark setae, hypandrium white. Cercus ( Figs 16, 17 ) long and broad, extending a long distance past tip of epandrium; outer margin convex in dorsal view, inner margin concave with numerous fine marginal setae; apically shallowly bifid. Epandrium ( Fig. 16 ) subcircular, dorsal margin bluntly triangular. Surstylus present, paler than epandrium, up curved, very long reaching to tip of cercus, bearing a few fine ventroapical setulae. Hypandrium long, narrow, divided ventrally at extreme base. Female: similar to male but antennae with stylus slightly less thickened, basal segments entirely and postpedicel dorsally darkened. F1 with basal spine of pv series distinctly longer than others. Wing with extreme base of Cu distinctly blackish. Abdomen with longer setulae on distal segments.

Type material. HOLOTYPE ♂, THAILAND: Loei Province, Nong Hin, Suan Sawan, Peangdin Waterfall, tufa stream, 627 m, 17.0596°N, 101.7422°E, 26.xi.2013, netted, A.R. Plant ( QSBG). PARATYPES: 1♂, 3♀, Loei Province, Wong Huy [Nong Hin], Suan Hom w/f, 579 m, 17.0415°N, 101.757°E, 22.xi.2013, 29.xi.2013, netted, A.R. Plant; 1♂, 5♀, Kanchanaburi Province, Khuean Srinagarindra NP, Huay Mae Kamint/Tourist centre, 210 m, 14.643°N, 98.994°E, 4–11/xii/2008, 12–19.ii.2009, MT, Somboon & Daorueng; 1♂, behind tourist centre, 210 m, 14.6539°N, 98.9975°E, 22–28.viii.2008, MT, Chatchawan & Boonkam ( QSBG & NMWC).

Etymology. The specific epithet anomala (Latin) refers to the unusual morphology of head, thorax and wing venation which are anomalous within the genus Hemerodromia . It is used as a noun in apposition.

Remarks. Hemerodromia anomala sp. nov. differs from all other described species of Hemerodromia in having the head strongly quadrate with the upper occiput shallowly concave, the thorax distinctly quadrate anteriorly and in the wing vein R2+3 joining R4 rather than connecting with the costa as is characteristic in Hemerodromia . The species has been captured during February, August, November and December in lowland (210–627 m) forests in Loei and Kanchanaburi provinces ( Fig. 76 ). The Loei localities were basic and mineral rich tufa streams. (Suan Hom, conductivity 414 µS/cm2, pH 8.08; Suan Sawan conductivity 418 µS/cm2, pH 7.84). The Kheuan Srinagarindra localities in Kanchanaburi were close to streams cutting through the underlying limestones and tufa deposits are present in the area. Hemerodromia anomala sp. nov. thus appears to be a stenotopic tufa stream specialist.

Figures

FIGURES 16 – 17. Male terminalia of Hemerodromia anomala sp. nov. 16, lateral view of terminalia; 17, dorsal view of cerci. Abbreviations: cer = cerci, epa = epandrium, hyp = hypandrium, pha = phallus, sur = surstylus.

FIGURES 73 – 81. Distribution of Hemerodromia spp. in Thailand at a resolution of 0.25 ° and symbols sized to 0.5 ° of latitude and longitude. 73, H. acutata Grootaert, Yang & Saigusa; 74, H. alphalutea sp. nov.; 75, H. anisoserrata sp. nov.; 76, H. anomala sp. nov.; 77, H. attenuata sp. nov.; 78, H. betalutea sp. nov.; 79, H. conspecta sp. nov.; 80, H. deltalutea sp. nov.; 81, H. deminuta sp. nov.