Schistostoma brandbergensis, Shamshev & Sinclair, 2006

Shamshev, Igor V. & Sinclair, Bradley J., 2006, The genus Schistostoma Becker from southern Africa, with an evaluation of its generic status (Diptera: Dolichopodidae s. l.: Microphorinae), African Invertebrates 47, pp. 335-346 : 338-340

Schistostoma brandbergensis sp. n.

Fig. 2

Etymology: The new species is named after its type locality, the Brandberg Massif.

Diagnosis: Hind tibia slender, with unmodified setation; proboscis nearly half as long as height of head; thorax mainly with black setation, acrostichals biserial, dorsocentrals uniserial; abdomen mostly with pale stiffened hairs.

Description:

Male.

Body black in ground-colour. Eyes holoptic, upper ommatidia considerably enlarged, ommatrichia present, distinct, but not dense. Occiput densely greyish pollinose, mostly clothed with black bristles, with some pale hairs in lower part; almost bare in upper part, except for postoculars. Ocellar tubercle with 2 pairs of proclinate bristles, anterior pair somewhat longer, posterior pair inserted at posterior margin.Antenna black; pedicel ringed with circlet of subequally short subapical bristles; postpedicel short conical, nearly 2.5 times longer than wide, pubescent with microtrichia; style somewhat paler in apical half, at most 1.5 times longer than postpedicel. Proboscis black, moderately long, nearly half as long as height of head, directed forward; palpus black elongate ovate, nearly half-length of labrum, pubescent with microtrichia and bearing scattered black setulae.

Thorax largely greyish pollinose, mainly with black setation; subshining in some views, with 2 darker subshining (viewed dorsally) vittae down dorsocentral rows and some brownish tinge down acrostichal rows; pleurae somewhat paler pollinose. Prothoracic episterna with 1 to several yellowish bristles. Postpronotal lobe with 1 long brownish bristle and 2 or 3 shorter brownish bristles anteriorly. Mesonotum with 1 presutural supra-alar, 2 notopleural (with additional shorter bristles varying in number and position), 2 or 3 short postsutural supra-alar, 1 long postalar and 4 similar scutellar bristles. Acrostichals arranged in 2 regular rows, rather short, lacking on prescutellar depression. Dorsocentrals uniserial, mostly subequal in length to acrostichals, 3 prescutellar pairs (especially posterior pair) considerably longer; 2 or 3 anterior pairs laterally off set from row. Anterior spiracle black.

Legs almost wholly dark brown to black, with intermixed pale to black setation; knees, extreme apex of femora and extreme base of tibiae yellowish; largely greyish pollinose, hind femur broadly shining posteriorly. Coxae and trochanters with ordinary brownish to yellow preapical bristly hairs. Fore femur slender, with some longer posterodorsal bristles, as long as two-thirds width of femur; shorter posteroventral bristles (subapicals longer) present. Fore tibia unmodified, mostly with inconspicuous setation, dorsal setulae somewhat longer. Fore tarsus unmodified, with ordinary setation. Mid femur with moderately long yellow posteroventral bristles, nearly as long as width of femur; similar black antero- and posterodorsal bristles (especially apically), bearing 1 long anterior bristle near middle. Mid tibia modified, somewhat curved and more stout in apical half, with shallow ventral excision near apex, with 1 row of moderately long posterodorsal bristles, 1 row of closely set anterodorsal spinule-like setae in apical third (1 preapical seta longer and spine-like), 1 row of yellowish posteroventral setae (longer in apical half), brush of about 7 strong setae of different lengths proximal to excision and some spinules beyond excision. Mid tarsus unmodified, tarsomere 1 with 1 long ventral bristle near base. Hind femur slender, with 1 row of mainly equally short anteroventral bristles (about 6 subapical bristles considerably longer) and 1 row of moderately long dorsal bristles, subequal in length to width of femur. Hind tibia slender, with somewhat longer dorsal setulae. Hind tarsus unmodified, with unmodified setation.

Wing (length 2.5–2.6 mm) hyaline, with brownish normally sclerotised veins, covered with uniform microtrichia. Basal costal bristle black, long. All veins complete. Costa with short setulae along anterior margin, distinct throughout; upper surface with distinct dorsal spinulae. Stigma pale brown, positioned along costa between veins Sc and R 1. Squama pale brownish, with pale hairs. Halter with yellow knob and dark brown stem.

Abdomen with tergites concolorous with mesonotum, mostly clothed with pale bristly hairs longer laterally; sternites somewhat paler, mostly with scattered short pale hairs, sternite 8 with 5–7 strong black bristles. Male terminalia ( Figs 2A–D ): Epandrium with pair of slender, finger-like dorsal lobes (dorsal part of surstylus), bearing some setulae, slightly arched; right lamella oblong, left lamella quadrate. Left ventral surstylus with digitiform extension; apex with toothed margin; right ventral surstylus broadly expanded and rounded apically. Hypandrium fused basally to each epandrial lamella; prolonged and slightly tapered anteriorly, bearing pair of apical setae, less than one-third of length of hypandrium; apex one-third basal width of hypandrium. Phallus sickle-shaped with hooked tip. Postgonite arising from pair of hypandrial arms which fuse above base of phallus, articulated to subepandrial sclerite and phallus; right postgonite shorter than surstylus, tapered apically; left surstylus broadly rounded apically, longer than right surstylus, arched medially and dorsally over phallus, base of postgonite strongly recurved or spiralled. Cercus short, bilobed, bearing several setae.

Female.

Similar to male, except as follows: eyes dichoptic, ommatidia uniform. Frons broad, with rather long marginal setae. Mid tibia unmodified, mid tarsomere 1 with unmodified setation. Abdomen with somewhat shorter and darker setation. Terminalia completely enclosed in abdomen.

Holotype: ơ ‘ Namibia: BRANDBERG/ Mason Shelter/ 21 ° 04'39"S 12 ° 05'43"E / 05–14.iii.2002, 1750 m / A.H. Kirk-Spriggs & E./ Marais/ Malaise trap riverbed’; ‘ HOLOTYPE / Schistostoma / brandbergensis / Shamshev & Sinclair’ (NMN).

Paratypes: 1 ơ 1 ^with same data as holotype ( NMN) .

Distribution and seasonal occurrence: Known only from type locality in Namibia and collected at the beginning of March, during the summer rainy period. The type series was not collected during the initial Brandberg Inventory Project ( Marais & Kirk-Spriggs 2000; Sinclair 2000 b, 2003), but obtained in a subsequent expedition, as described by Mey (2003). The type locality, Mason Shelter is a plateau surrounded by rugged hills and smooth granitic boulders ( Mey 2003, figs 3, 4, 7; 2004, figs 3, 4). The Malaise trap was set along well-vegetated ephemeral watercourses (Kirk-Spriggs, pers. comm. 2006). There were temporary pools present when the expedition arrived, indicating that it had rained earlier, and heavy rains occurred during the time the trap was set. Mason Shelter is the upper drainage area of the Nawuarib River (Mey 2004).

Figures

Fig. 2. Schistostoma brandbergensis sp. n.: (A) Hypopygium, right lateral view; (B) Hypopygium, hypandrium and cercus removed, left lateral view; (C) Hypandrium, dorsal view; (D) Phallus and internal structures, right lateral view.Abbreviations:cerc – cercus; epand – epandrium; ej apod – ejaculatory apodeme; hypd – hypandrium; hypd arm – hypandrial arm; pgt – postgonite; ph – phallus; sur – surstylus. Scale bar = 0.1 mm.