Thinolestris Grootaert & Meuffels

Grootaert, Patrick & Evenhuis, Neal L., 2006, On the distribution of the marine genus Thinolestris Grootaert & Meuffels (Diptera, Dolichopodidae) with a description of a new species from Singapore, Malaysia and Brunei, Zootaxa 1134, pp. 59-68 : 60-61

Genus Thinolestris Grootaert & Meuffels

Thinolestris Grootaert & Meuffels, 1989: 32 (Type species Thinolestris luteola Grootaert & Meuffels, 1989: 33 , by original designation).

Head ellipsoid in lateral view with a large proboscis, occupying about one third of head length. Face broad; clypeus protruding in both sexes. A pair of strong fronto­orbitals, a pair of strong ocellars and a pair of strong verticals. Antenna ( Fig. 1 ) with third segment triangular, about 1.5 times as long as wide. Arista apical, always black, 1­segmented; aristal pit present. Palp large, without apical bristles ( Fig. 2 ); yellow in all species. Mouthparts ( Figs 5–7 ).

Legs rather short, unmodified, unornamented, with few major setae. Legs yellow with apical tarsomeres black. Only fore femur with some distinct bristles: dense pale, ventrals, a row of spine­like anteroventrals on apical half, and a row of posteroventrals.

Thorax orange­yellow in ground­colour or black, covered by thick grey dusting. Thoracic bristles strong: acrostichals absent, 4 dorsocentrals, 1 humeral, 1 posthumeral, 2 short notopleurals, 1 sutural, 2 supraalars and 1 postalar; a pair of very long crossed scutellars.

Abdomen with 5 externally visible segments, following segments hidden. Tergites covered with short hairs and rather short marginals. Hypopygium bent under abdomen with a shining black hypandrium and a shining black projection from fifth sternite hooking into hypandrium. Cerci long, strap shaped. Aedeagus bifurcate.

Wing with brownish­grey membrane and yellowish brown veins. Costa with short strong, interspaced spine­like bristles, especially long on basal quarter of costa.

Female in most characters identical to male. Eighth segment short. Tergite 10 divided medially with each hemitergite bearing about 10–11 slender spines ( Figs 3–4 ).

Remarks: The basal segment of the arista is fused with the rest of the arista in this genus ( Fig. 1 ). A separation seems to be present when viewing the antenna at low magnification. This is however the aristal pit and not the joint between two segments.

Figures

FIGURES 1 – 4. Thinolestris nigra sp. nov. 1. antenna (male, Brunei), aristal pit indicated; 2. palp (male Brunei); 3. ovipositor female laterally (Singapore); 4. ovipositor female dorsally (Singapore).

FIGURES 5 – 7. Thinolestris nigra sp. nov. male (Brunei). 5. mouthparts (palp, maxilla and labium removed); 6. labium and labella with pseudotracheae; 7. hypopharynx. Scale 0.1 mm.