Grootaertia skorpionensis, Grichanov & Kirk-Spriggs & Grootaert, 2006

Grichanov, I. Ya., Kirk-Spriggs, A. H. & Grootaert, P., 2006, An annotated checklist of Namibian Dolichopodidae (Diptera) with the description of a new species of Grootaertia and a key to species of the genus, African Invertebrates 47, pp. 207-207 : 210-212

Grootaertia skorpionensis sp. n.

Figs 1–5

Etymology: The specific epithet, skorpionensis , refers to the type locality. Description:

Male.

Measurements (mm): body length, 2.1; antenna length, 0.8(^)–0.9(ơ); wing length/ width, 1.5/0.5; hypopygium length, 0.6.

Body generally brown, with brown setae.

Head: Frons and face black. Ocellar tubercle prominent, with pair of strong setae. One strong vertical seta present laterally on frons, a weaker postvertical positioned as linear continuation of postocular setal row; postocular setae brownish above, white laterally and below. Occiput flat, perpendicular to frons surface.Ventral postcranium with several short cilia. Face widest beneath antennae, gradually narrowed towards clypeus. Clypeal suture rather prominent. Ratio of height of face to its maximal width to its minimal width 15:7:4.Antenna 1.6× longer than head height, black-brown; scape with 2–3 distinct dorsal hairs; pedicel with ring of short apical setulae; postpedicel appears to be entirely fused with stylus, without any trace of division, thus being very long, swollen at base, gradually narrowing to apex, entirely covered with long dense hairs. Length ratio of scape to pedicel to postpedicel 3:3:33. Palpus and proboscis brown, with sparse hairs; palpus short, subtriangular, with one apical seta; proboscis stout, elongated.

Thorax: Mostly dark brown mesonotum; humeri, notopleura, scutellum and adjacent part of mesonotum yellow, sometimes scutellum brownish at base; pleura yellow-brown, more yellow in upper half, with small black spot on pteropleura; mesonotum flattened in posterior third. Five pairs of strong dorsocentral setae decreasing somewhat in length anteriorly. Acrostichal setae absent. Two fine proepisternal setae. Scutellum with pair of strong setae and pair of microscopic lateral hairs.

Legs: Mainly reddish yellow, with mostly brownish coxae; tarsi brown from tip of basitarsus. Fore coxa with short hairs and several light setae in apical half; mid and hind coxae with one light external seta. Femora without setae and long hairs. Fore tibia with 2–3 short apicoventral setae. Mid tibia with one anterior and one posterodorsal setae at basal 1/5, 3–4 apical setae; tarsomeres 1–4 with short apical setulae. Hind tibia with several short dorsal setae. Length ratio of fore femur to tibia to tarsus (tarsomeres 1–5) 23:22:13:6:4:3:3. Same ratio for middle leg 28:31:18:8:6:4:4. Same ratio for hind leg 30:32:12:11:7:4:3.

Wing: Elongate-oval, simple, hyaline; veins brown; posterior wing margin evenly convex; maximum wing width just before the end of CuA 1. Costa lacking long hairs. Ratio of part of costa between R 2+3 and R 4+5 to that between R 4+5 and M 1+2 9:3. R 4+5 and M 1+2 slightly convex anteriorly, parallel in apical part. Ratio of apical to basal part of M 1+2 (from r–m) 30:16. Crossvein m–cu slightly convex. Ratio of crossvein m–cu to maximal distance between R 4+5 and M 1+2 to apical part of CuA 1 5:5:16. Anal vein fold-like, anal lobe poorly developed, anal angle obtuse. Alula reduced. Lower calypter small, yellow, with greatly reduced cilia. Halter yellow.

Abdomen: Brown, lighter laterally and ventrally, covered with short light setae. Tergum 7 semicircular, narrow, lying conformably with tergum 6. Tergum 8 large, covering left basolateral foramen. Epandrium shining black-brown, pear-shaped (lateral view). No epandrial seta. Hypandrium (epandrial lobe?) forming long pointed lobe positioned at left distoventral angle of epandrium. Aedeagus long, widened in middle; lateral lobes of aedeagus long, thin, pointed apically. Surstyli brown, glabrous, two pairs, positioned apicodorsally. Cercus yellow, visible, with several long dorsal setae.

Female.

Similar to ơ except lacking male secondary sexual characters. Postpedicel tapering, 3× longer than high at base. Length ratio of scape to pedicel to postpedicel to stylus (1 st and 2 nd segments) 3:3:9:2:19.

Holotype: ơ ‘ Namibia: Lüderitz District / Skorpion area / 27°49'S 16°36'E / 09–12.viii.1997 / E. Marais & A.H. Kirk-Spriggs / yellow trays 3 // Holotype ơ / Grootaertia / skorpionensis Grichanov [laser printed on red card]’ (NMNW type # T 602).

Paratypes: 2ơ same data as holotype except: / ‘blue trays 1 // Paratype ơ / Grootaertia / skorpionensis Grichanov [laser printed on red card]’ [in one vial]; 1^same except: / ‘yellow trays 1’; 3ơ 4^same except: / ‘yellow trays 4’ [in one vial]; 4ơ 2^same except: / ‘yellow trays 4’ [in one vial] (all preserved in alcohol, NMNW series # T 602); 1ơ same except: / ‘yellow trays 3’ (in glycerol after alkalisation, mounted on pin in a cavity of polymer film covered with adhesive tape; ZIN).

Distribution: Namibia. The type material originates from the Succulent Karoo Biome in south-western Namibia, as defined by Irish (1994), and the species appears to be restricted to this biome. The type material was sampled as part of an environmental impact assessment, and the type locality has subsequently been developed for a zinc mine. The area is however, fairly homogenous, and the species is expected to occur elsewhere in the same biome.

Similar species: Differing from other species of the genus in the morphology of the antennae. Scape bearing 2–3 distinct dorsal hairs; postpedicel appears to be entirely fused with stylus, with no trace of division, thus being very long, swollen at base, gradually narrowing to apex, entirely clothed in long dense hairs. Such male secondary sexual character as fused postpedicel and stylus appears to be unique in the subfamily Medeterinae . Elongated postpedicel (particularly in females) is remarkable in the genus. For example, only G. kuznetsovi Grichanov and G. irwini Grichanov males have elongated postpedicel, 1.5× longer than high at base. Grootaertia Grichanov is endemic to southern Africa with G. skorpionensis sp. n. here described from Namibia and seven species described previously from Western Cape and Eastern Cape provinces of South Africa (Grichanov 1999 b, 2000 a). The new species may be easily identified by use of the above key.

Figures

Figs 1–5. Grootaertia skorpionensis sp. n.: (1) ơ antenna, (2) ^antenna, (3) wing, (4) hypopygium, left lateral aspect, (5) hypopygium, right lateral aspect.