Hemerodromia ocellata, 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 : 37

Hemerodromia ocellata sp. nov.

( Figs 55–57 , 91 )

Diagnosis. A yellow species with mediotergite slightly obscured brownish. Posterior margin of scutum with well defined black ‘scutoscutellar eye’. Sct absent. Cell bm+dm short. Epandrium with cluster of strong bristles posteroventrally. Surstylus extending distinctly beyond tip of epandrium, upper process almost circular apically with minute dentate setulae on margins; lower process linear with two large leaf-shaped setae apically.

Description. Male: Body length 2.2 mm; wing length 1.7 mm. Head. Black, dusted greyish; antenna and mouthparts pale whitish yellow, all setae pale; one pair proclinate ocl; postocular setae uniseriate, merging above with 1–2 pairs small vtl and several fine setulae on vertex; frontal setulae apparently absent. Antenna with postpedicel ~ 3X long as wide, a few minute outstanding setulae subapically; stylus shorter, ~0.3–0.4X long as postpedicel; scape with distinct fine dorsal seta. Thorax. Dusted greyish. Ground colour yellow; mediotergite rather vaguely obscured brownish but with yellow colour evident, prothoracic ‘collar’ very narrowly darkened medially; anterior spiracle not distinctly emarginated above with small dark mark; ‘scutoscutellar eye’ strongly defined, black; sutures between prothoracic ‘collar’ and anterior margin of scutum, and at margins laterotergite blackish. All setae yellowish, minute, a pair of distinct npl, sct absent. Legs. Pale yellow. C1 ~1.2X longer than distance between C1 and C2, all setulae minute but with a few longer hairs dorsally. F1 ~ 1.1X long as C1, ~ 6X long as wide, evenly inflated, hardly constricted on proximal 0.3; femoral formula ~ 6/16/16 +1/7, denticles black, rows converging apically; spines yellow, pv and av rows short, becoming somewhat longer proximally with basal spine longest. T1 ~ 0.6–0.7X long as F1, evenly curved, ventral face shallowly concave; with ~ 16 similarly sized sharply pointed spinose setae ventrally; short ciliation of distinct proclinate hairs dorsally on distal 0.3; ventroapical spur very small with ventroapical erect black spinose seta arising from near its base. Mid and hind legs slender with only small pale setulae. Wing. Membrane distinctly darkened by yellowish brown microtrichia, hyaline basally. Veins blackish, hyaline basally, darker about base of R2+3 and M1+2 and posterior border of cell bm+dm; veins C, R4 and distal 0.5 of R2+3 yellowish. Marginal setulae pale. R2+3 almost linear, joining C ~ 0.7X distance between end of R1 and R4; length of C between ends of R2+3 and R4 ~1.1X long as R4; R4 almost linear; R5 ~ 2.1X long as R4, almost linear; R4+5 fork distal to M1+2 fork by ~ 1.2X 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 greyish yellow. Abdomen. Yellow with tergites 2–6 blackish, tergite 2 laterally yellow; a few distinct hairs on posterior margins of distal segments. Terminalia. Black. Cercus elongate ( Figs 55, 56 ), extending beyond tip of epandrium, slightly inflated apically in lateral view; a small subapical thickening on inner face lacking strong seta. Epandrium ( Fig. 55 ) small subquadrate with posterior margin almost linear for a short distance; several very strong bristly setae near pv margin. Surstylus present, extending distinctly beyond tip of epandrium; almost circular apically with series of dense minute dentate setulae on inner margin ventrally and posteriorly. A narrow process emerging beyond tip of epandrium, below surstylus (possibly lower lobe of surstylus), slightly curved, with distinct leaf-like setulae at tip and preapically ( Fig. 57 ). Hypandrium very large, ~ 2X long as epandrium ( Fig. 55 ); distinctly keel-shaped with few distinct bristles but distinctly pilose over much of its surface. Female: Unknown.

Type material. HOLOTYPE ♂, THAILAND: Surat Thani Province, Khao Sok NP, Bang Huaraed, 122 m, 8°54.555'N 98°30.522'E, 13–20.i.2009, MT, Pongphan [T3914]( QSBG).

Etymology. The specific epithet is from the Latin ocellata (eye) in reference to the strongly defined ‘subscutellar eye’ marking.

Remarks. Hemerodromia ocellata sp. nov. is very similar to H. anisoserrata sp. nov. differing from it primarily in having a smaller epandrium, larger hypandrium, cercus somewhat narrower and lacking distinct setae on the subapical thickening of the inner face. The narrow process (lower process of surstylus?) emerging beyond the tip of epandrium is linear (sharply bent downwards at ~90° in H. anisoserrata sp. nov.) and bears 2 strong leafshaped specialised setae at its apex. The species is also similar to H. serrata Saigusa & Yang 2002 . For further discussion of the differences between these three species see notes under H. anisoserrata sp. nov. Hemerodromia ocellata sp. nov. is only known from the holotype male taken in January at one lowland (122 m) locality in Surat Thani Province, southern Thailand ( Fig. 91 ).

Figures

FIGURES 55 – 57. Male terminalia of Hemerodromia ocellata sp. nov. 55, lateral view of terminalia; 56, dorsal view of cerci; 57, distal part of lower lobe of surstylus. Abbreviations: cer = cerci, epa = epandrium, hyp = hypandrium, lsur = lower lobe of surstylus, usur = upper lobe of surstylus.

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.