Hemerodromia deprimatura, Plant, 2020

Plant, Adrian R., 2020, New species of Hemerodromia Meigen (Diptera: Empididae: Hemerodromiinae) associated with limestone karstic waters in Thailand, Zootaxa 4758 (3), pp. 549-560 : 552-553

Hemerodromia deprimatura sp. nov.

( Figs 3–4 , 13 )

Diagnosis. A dirty yellow species with a triangular brownish marking behind eye on lower occiput. Male terminalia with inner margin of cercus evenly concave in dorsal view, tip of surstylus L-shaped and a narrow process emerging beyond tip of surstylus (possibly lower surstylus) with very narrow shaft and small black subcircular process apically.

Description. Male: body length 2.1 mm; wing length 1.7 mm. Head. Slightly elongate. 1.4X long as deep, upper occiput making smooth curve where meeting vertex, hardly bulging. Dirty yellow with pale dusting, lower occiput with brown mark behind eye becoming broader ventrally (appearing triangular in lateral view). Antenna and mouthparts whitish. One pair of minute reclinate ocellar setulae; 3–4 pairs of vertical setulae positioned in linear series parallel with upper eye margin, clearly distinguished from other fine hairs; postocular and lower occipital setulae minute.Antenna with postpedicel ~2.5X long as wide, stylus of similar length. Thorax. Dirty whitish yellow with greyish dust; darker on posterior margins of scutellum and mediotergite; blackish about anterior spiracle, ‘scutoscutellar eye’ and ventrally between insertion points of front coxa. All setae yellowish, minute, but notopleural distinct and pair of weak scutellars. Legs. Dirty whitish yellow, apical tarsomeres of all legs very slightly darker. C1 ~1.2–1.3X longer than distance between base of C1 and C2; C1, C2 and C3 with all setulae minute. F1 ~1.0–1.1X long as C1; F1 4–5X long as wide, very slightly constricted on inner face at 0.2 from base. F1 with two parallel rows of 17–21 minute black denticles ventrally, either side of which is linear series of less numerous and inconspicuous fine yellow bristles, noticeably stronger around 0.2 from base. T1 ~0.8X long as F1, slightly curved, ventral face shallowly concave bearing two rows of minute, sharply pointed, blackish spinose setulae; ventroapical spur weakly developed; distinct ventroapical erect black spinose seta present. Wing. Membrane clear but darkened on distal 0.9 by blackish microtrichia. Veins greyish on distal 0.9, paler on proximal 0.1. R 2+3 linear, joining C ~ 0.7X distance between ends of R 1 and R 4. Length of C between ends of R 2+3 and R 4 ~1.7–1.8X long as R 4. R 4 linear, not at all Sshaped, angle with R 5 at extreme base ~ 70°. R 5 ~2.2X long as R 4. R 4+5 fork distal to M 1+2 fork by ~1.5X length of R 4. R 5 and M 1 almost linear, distinctly convergent distally. Cell bm+dm rather long, ending just beyond end of R 1. Halter dirty white. Abdomen. Tergites blackish but tergite 1 pale with narrow transverse black fascia at middle, tergite 7 and all sternites more uniformly pale. All setulae small and dark, longer on posterior margin of 7 th segment. Terminalia dirty yellowish. Cercus ( Figs 3–4 ) elongate, extending slightly beyond tip of epandrium, slightly inflated apically in lateral view, some fine hairs dorsally and on inner face slightly stronger dorsoapically; inner margin distinctly evenly concave in dorsal view. Epandrium ( Fig. 4 ) bluntly pointed apically, covered with fine tomentum and a few strong bristles apically. Surstylus present, extending distinctly beyond tip of epandrium, rather broad, Lshaped apically with broad dorsal process; narrow process emerging beyond tip of surstylus (possibly lower lobe of surstylus) with very narrow shaft and small black subcircular process apically (apparently flat on inner face, more convex on outer). Hypandrium ( Fig. 4 ) large, pointed apically, covered with fine tomentum and only a few distinct bristles. Female: similar to male but abdomen with terminalia elongate, somewhat ovipositor-like.

Type material. HOLOTYPE ♂: THAILAND, Phang Nga Province, Sa Nang Namora waterfall, tufa stream, 59 m, 8.51063°N, 98.54140°E, 16.i.2019, netted A. R. Plant ( QSBG) . PARATYPES: 2♂, 2♀, same data as holotype ( QSBG) .

Etymology. The specific epithet is derived from the Latin deprimatur, meaning ‘perfectly poised’ in reference to the apparent hunting posture adopted by adult Hemerodromia when searching for prey.

Remarks. This species is very similar to and clearly closely related to H. anisoserrata Plant and H. ocellata Plant from Thailand and H. serrata Saigusa and Yang from China (Henan). The new species may be distinguished by the triangular brown marking on the lower occiput and the form of the male terminalia in which the cercus is evenly curved on the inner face (irregular in anisoserrata / ocellata / serrata), the elongate bluntly pointed epandrium (apically broad in anisoserrata, short and broad in ocellata , apically narrower in serrata) and the complex shapes of the two elongate processes of the upper and lower surstylus (very different shapes in anisoserrata / ocellata / serrata). Hemerodromia deprimatura sp. nov. is only known from a calcareous tufa stream in southern Thailand ( Fig. 13 ).

Figures

FIGURES 3–4. Male terminalia of Hemerodromia deprimatura sp. nov. 3, lateral view of terminalia; 4, dorsal view of cerci. Abbreviations: cer=cerci, epa=epandrium, hyp=hypandrium, lsur =lower lobe of surstylus, usur=upper lobe of surstylus.

FIGURES 12–16. Distribution of five new species of Hemerodromia in Thailand at a resolution of 0.25° and symbols sized at 0.25° of latitude and longitude. Occurrence of limestone karst landforms is indicated by grey shading. 12, Hemerodromia aliaextriata sp. nov.; 13, Hemerodromia deprimatura sp. nov.; 14, Hemerodromia oretenebraea sp. nov.; 15, Hemerodromia pairoti sp. nov.; 16, Hemerodromia samoha sp. nov.