Hesperempis sibirica, Shamshev, 2007

Shamshev, Igor V., 2007, A new species of the genus Hesperempis Melander (Diptera: Empididae) from Siberia, Zootaxa 1554 (1), pp. 63-65 : 63-65

Hesperempis sibirica sp. nov.

( Fig. 1 )

Diagnosis. In having a wholly yellow body the new species is very similar to H. sanduca but can be readily distinguished from it by the entirely yellow legs (vs. hind tarsomeres 4 and 5 black). H. mabelae , according to the original description, has a greyish black body.

Description. Male. Wing length 2.1–2.2 mm. Head wholly yellow, including antennae, palpi and mouth-parts; occiput and frons finely greyish pollinose; setation pale. Eyes bare, dichoptic, with ommatidia equally small. Frons broad, with few marginal setulae. Ocellar triangle prominent, with short latero- proclinate setae. Postvertical and postocular setae very short; additionally, occiput with scattered bristly hairs on lower part. Antenna with scape short, setose, subequal in length to globular pedicel; postpedicel with broad base, strongly tapered, about 2.5 times as long as wide; style cylindrical, three-segmented, nearly 1/3 length of postpedicel, segment 10 rather long, about half as long as segments 8 and 9 combined. Proboscis short, directed forwards; palpus short.

Thorax wholly reddish yellow, with pale inconspicuous setation; scutum viewed dorsally or anteriorly finely light grey pruinose, with 2 narrow dull vittae (one between acrostichal and dorsocentral bristles on each side) but when viewed posteriorly appearing almost wholly (except prescutellar depression) dull; entire mesopleuron with similar uniform pruinosity. Prosternum isolated, not fused to proepisternum. Proepisternum and antepronotum with few setulae. Postpronotal lobe with 1 very short bristle and several setulae. Mesonotal bristles mostly slightly prominent; acrostichals and dorsocentrals subequally very short (including prescutellars); the former irregularly biserial, lacking on prescutellar depression; the latter arranged in 1–2 rows, offset from row anteriorly, extending to base of scutellum; several setulae present on presutural and postsutural supra-alar faces, 1 rather short notopleural bristle (with several additional setulae), postalar callus with 3 setulae, scutellum with 5 pairs of bristles. Laterotergite bare.

Legs wholly yellow, unmodified, lacking prominent bristles. Coxae and trochanters with unmodified pale bristly hairs. Fifth tarsomere on all legs flattened; pulvilli small, shorter than tarsal claw.

Wings finely yellowish infuscate, with brownish yellow veins; no bristle at wing base; stigma hardly visible, brownish yellow, elliptical, overlapping apex of vein R 1; anal lobe prominent, obtuse. Sc complete; R 2+3 straight on apical part; radial fork present, V-shaped, with base opposite apex of vein R 2+3; distance between apices of veins R 2+3 and R 4 subequal to that between veins R 4 and R 5; veins R 5 and M 1 parallel before wing-apex; cell dm broad, somewhat longer than basal cells, produced apically; m-m crossvein long, M branches widely separated; dm-cu crossvein slightly concave; vein CuA 1 nearly 1.5 times longer than dm-cu crossvein. Apex of cell cup slightly rounded, vein A1 long, reaching wing margin. Halter yellow.

Abdomen wholly yellow, finely greyish pollinose, covered with short pale bristly hairs, longer posteriorly.

Terminalia unrotated, slightly arched anteriorly in dried specimens; with cercus (except brownish upper margin), basal half of epandrial lamella (brownish in apical half) and hypandrium yellow; finely pollinose, with short pale setulae. Epandrium deeply emarginate, with rather broad dorsal bridge. Surstylus absent. Hypandrium large, subrectangular, prolonged in long narrow apical lobe (postgonites?), with several long setae, basally fused to epandrium. Cercus broad, tapered to rounded tip on apical third; covered with long setae and bearing numerous spinules on apical part; hypoproct well developed, broad with rounded apex. Phallus arched posteriorly, apical third mostly membranous, with numerous spinules.

Female. Unknown.

Material examined: Holotype male: [in Cyrillic] RUSSIA, zh.d.st. [abbreviation for "zheleznodorozhnaya stantsiya" = railway station] Dachnaya, 32 km S of Irkutsk / V. Richter , 20.VI.1971 [deposited in ZIN].

Paratype: 1 male, RUSSIA: Padun / Irkut. obl. [= Irkutsk Province] / Monchadsky , 10.VII. [1]956; UV trap 22.00- 23.00 [ ZIN].

Derivatio nominis. The new species is named after the region of origin, Siberia.

Distribution. Russia: East Siberia (Irkutsk Province).

Discussion. It is evident now that Hesperempis is relatively widespread, occurring in eastern Asia and eastern and western parts of North America. However, in Continental Asia these flies have been surprisingly rarely collected and are very poorly represented in collections. Apparently, this genus shows a trans-Pacific vicariance distribution pattern that is not uncommon among Diptera .

Sinclair and Saigusa (2002) indicated several examples among genera of Empidoidea. However, this list will likely become longer, because relationships within many groups of empidoids, including huge generic groups such as Empis Linnaeus , Rhamphomyia Meigen and Hilara Meigen are not yet resolved.

Recently, Sinclair and Cumming (2006) discussed the relationships of Hesperempis within Empidoidea. The new Hesperempis species described in the present paper wholly agrees with the set of characters that these authors applied for their analysis thus supporting the current concept of the genus.

Hesperempis sibirica sp. nov. appears very similar to H. sanduca , which has also been examined by the author (material in ZMLU). However, more precise relationships of the new species will be presented within a forthcoming analysis involving all other undescribed and described species of Hesperempis and some closely related genera (Cumming, Brooks & Saigusa, in prep.).

Acknowledgements. I am indebted to Jeffrey Cumming, Scott Brooks (Agricultural Canada, Ottawa) and Toyohei Saigusa (Fukuoka, Japan) who provided unpublished data for comparison. I thank Roy Danielsson for his help during my work at Lund University and Bradley Sinclair for checking English and interesting discussions concerning empidoids during my stay in the Zoologisches Forschungsmuseum Alexander Koenig, Bonn. My visits to Lund and Bonn were supported by the Sweden Institute and the Deutsche Forschungsgemeinschaft (DFG), respectively.

Figures

FIGURE 1. Male Hesperempis sibirica sp. nov., A, lateral view of postabdomen; B, lateral view of terminalia; C, dorsal view of terminalia. Scales: A—1.0 mm; B, C—0.1 mm. Abbreviations: cerc—cercus, ej apod—ejaculatory apodeme, epand—epandrium, goncx apodeme, hypd—hypandrium, ph—phallus.