Schistostoma kalkgat, 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 : 341-343

Schistostoma kalkgat sp. n.

Fig. 3

Etymology: The new species is a noun in apposition, named after the farm where the trap was established.

Diagnosis: Hind tibia somewhat tapered toward apex, bearing 1 row of dorsal bristles on apical half with 3 or 4 subapicals long and strong. Mid tibia with dorsal subapical spinule-like setae, tuft of similar ventral setae before excision and ventral spinules at apex.

Description:

Male.

Body black in ground-colour. Eyes holoptic, upper ommatidia considerably enlarged, border between upper and lower ommatidia distinct, ommatrichia present, distinct. Occiput yellowish grey pollinose, clothed with brownish yellow bristles, with some pale hairs on lower part; almost bare on upper part, except postoculars. Ocellars missing. Antenna black; pedicel ringed with circlet of subequally short subapical setae; postpedicel short conical, 2.3 times longer than wide, pubescent with microtrichia; style partly missing. Proboscis long, somewhat longer than head height, apparently directed forward, labrum largely yellowish brown, paler proximally. Palpus black, elongate ovate, considerably shorter than labrum, pubescent with microtrichia and bearing scattered black setulae.

Thorax largely greyish pollinose, mainly with yellowish brown setation; subshining in some views, with 2 darker subshining (viewed dorsally) vittae down dorsocentral rows; pleurae somewhat paler pollinose (bristles mostly lost during processing malaise trap material). Prothoracic episterna with 1 yellowish bristle.Postpronotal bristle missing, postpronotal lobe with 6 subequally long pale bristly hairs. Mesonotum with 1 presutural supra-alar surrounded by additional shorter and paler bristly hairs, 2 notopleural bristles, accompanied by additional shorter bristly hairs varying in number and position, 2 or 3 short postsutural supra-alar, 1 postalar (missing) and 4 scutellar (3 missing) bristles. Acrostichals arranged in 2 regular rows (at least in anterior part of scutum, otherwise missing), moderately long. Dorsocentrals irregularly biserial in anterior part of scutum, otherwise missing, subequal in length to acrostichals.

Legs almost wholly brownish, with intermixed pale to black setation; femora somewhat darker, knees, extreme apex of femora and extreme base of tibiae paler (especially on fore legs); largely greyish pollinose, hind femur broadly shining posteriorly. Coxae and trochanters with ordinary brownish preapical yellow bristly hairs. Fore femur slender, with some longer posterodorsal bristles, bearing short posteroventral setae (subapicals longer). Fore tibia simple, with inconspicuous setation. Fore tarsus unmodified, with simple setation. Mid femur with moderately long yellow posteroventral bristles, similar antero- and posterodorsal bristles (especially apically), bearing 1 long anterior bristle near middle. Mid tibia modified, somewhat curved and more stout on apical third, with shallow ventral excision near apex, bearing some black dorsal subapical spinule-like setae, tuft of similar ventral spinule-like setae before excision and some ventral spinules at apex. Mid tarsus unmodified, tarsomere 1 with 1 long ventral bristle near base. Hind femur slender, with 1 row of mainly equally short anteroventral bristles (3 or 4 subapical bristles longer) and 1 row of rather long dorsal bristles. Hind tibia somewhat tapered toward apex, with 1 row of black dorsal bristles in apical half (3 or 4 subapicals long and strong), covered with dense appressed setulae posteriorly near apex. Hind tarsus unmodified, with simple setation.

Wing (length 2.7 mm) hyaline, with brownish normally sclerotised veins, covered with uniform microtrichia. Basal costal bristle moderately long, brownish yellow. All veins complete. Costa with short setulae along anterior margin, distinct throughout; upper surface with distinct dorsal spinulae. Stigma brownish yellow, positioned along costa between veins Sc and R 1. Squama pale brownish, pale hairs. Halter with yellow knob and brown stem.

Abdomen with tergites concolorous with mesonotum, clothed with pale to brownish bristly hairs longer laterally; sternites with scattered short hairs. Male terminalia ( Figs 3A–C ): Epandrium with pair of slender, finger-like dorsal lobes (part of surstylus), bearing some setulae, mostly straight; right lamella oblong, left lamella quadrate. Left ventral surstylus with digitiform extension; apex with toothed margin; right surstylus broadly expanded and rounded apically. Hypandrium fused basally to each epandrial lamella; prolonged and distinctly tapered anteriorly, bearing pair of apical setae, less than one-third length of hypandrium; apex one-fourth of 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 slightly ventrally beneath phallus, base of postgonite strongly recurved. Cercus short, bilobed, bearing several setae.

Female.

Similar to male, except as follows: Eyes dichoptic, ommatidia uniform, bare. Frons broad, with rather short marginal setae. Mid and hind tibiae unmodified, mid tarsomere 1 with simple setation. Wing length 2.1 mm. Abdomen with somewhat shorter setation. Terminalia enclosed in abdomen.

Holotype: ơ ‘S.AFR:West CapeProv./ Knersvlakte (east of/ Vanrhynsdorp) Farm/ Kalkgat Noord’; ‘ S 31 ° 07'30" / E 18 ° 55'30"; malaise/ 20–27.ix.2000 / U. Schmiedel leg.’; ‘ HOLOTYPE / Schistostoma / kalkgat / Shamshev & Sinclair’ (NMSA).

Paratype: ^with same data as holotype ( NMSA) .

Distribution and seasonal occurrence: This species is known only from Western Cape, South Africa, collected at the end of September. The type locality is in the Knersvlakte of southern Namaqualand, a region that receives reliable winter rainfall (May to August) of between 100 and 175 mm (Cowling et al. 1999; Schmiedel & Jürgens 1999). The Knersvlakte is one of three centres of plant endemism in Namaqualand ( Cowling & Pierce 1999). The region consists of a rolling coastal plain, bordered in the west by the Atlantic Ocean, the Hardeveld uplands to the north and the Cape Fold Belt in the east ( Schmiedel & Jürgens 1999). The major vegetation surrounding the type locality is Lowland Succulent Karoo, a dwarf succulent and species-rich shrubland (Cowling et al. 1999). The material was collected in Malaise traps as a part of the BIOTA Southern Africa Project ( Fig. 4 ).

Figures

Fig. 3. Schistostoma kalkgat sp. n.: (A) Hypopygium, right lateral view; (B) Hypopygium, hypandrium and cercus removed, left lateral view, (C) Hypandrium, dorsal view. Abbreviations: cerc – cercus; epand – epandrium; ej apod – ejaculatory apodeme; hypd – hypandrium; pgt – postgonite; ph – phallus; sur – surstylus. Scale bar = 0.1 mm.

Fig. 4. Acacia Karoo stand on the farm Kalkgat Noord (C. kalkgat type locality), in the north-eastern Knersvlakte, October 2000. Photograph by Ute Schmiedel.