Stilpon malayensis, Shamshev & Grootaert, 2004

Shamshev, Igor V. & Grootaert, Patrick, 2004, A Review Of The Genus Stilpon Loew, 1859 (Empidoidea: Hybotidae) From The Oriental Region, Raffles Bulletin of Zoology 52 (2), pp. 315-346 : 332-334

Stilpon malayensis , new species

( Figs. 54-59 )

Material examined. – Holotype - male, SINGAPORE: Nee Soon , swamp, sample n 22054, 4 Dec.2002, coll. P. Grootaert ( ZRC).

Diagnosis. – Species with brown mesoscutum and yellow pleurae, otherwise similar to S. lek differing from it by armature of male mid femur and details of male terminalia. Description. – Male. Head black in ground-colour, with minute ocellars and long inner verticals. Antenna and palpus brownish yellow. Postpedicel nearly 2.0 times longer than wide. Style about 5 times longer than postpedicel.

Thorax with brown prothoracic sclerites and mesoscutum, otherwise yellow. Scutum entirely tomentose. Postpronotal bristle long, inclinate. Dorsocentrals in multiple rows, complete posteriorly. Acrostichals 2-serial, complete posteriorly.

Legs with colour pattern: mid femur in apical 1/3, hind femur in apical 3/4, mid and hind tarsomere 5 brownish, fore tarsomere 5 black, fore tibia and fore tarsomere 1 brownish yellow. Mid coxa with 2 brown bristles on outer side. Hind trochanter lacking spinules. Mid femur ( Fig. 54 ) slender, with 2 short dark posteroventral spines in basal 1/3, 1 similar anteroventral spine in apical 1/3 and yellow bristle in extreme base. Hind femur (viewed laterally) more or less evenly thickened, with row of anterodorsal bristles becoming longer toward apex and row of prominent dorsal bristles. Fore tibia lacking prominent ventral bristles. Mid tibia with rows of ventral spinules and 1 longer subapical spinule. Hind tibia unmodified.

Wing ( Fig. 55 ) normally developed, covered with uniform microtrichia; more or less uniformly, rather deep infuscate. Costal vein with long setulae along anterior margin. Vein R2+3 about 2.5 times longer than Rs. Distance between apices of R2+3 and R4+5 1.2 times longer than distance between apices of R1 and R2+3. R4+5 and M slightly divergent and arcuate in apical part. Halter with elongate, contrast black knob and pale stem.

Abdomen largely dirty yellow, bearing mostly scattered dark setulae which are longer on pregenital segments, with all tergites (except segment 8) subequal in length, tergites 1-2 unmodified. Gland-like structures present between tergites 4-3 and 3-2 ( Fig. 83 ); posterior space consisting of three parts, with lateral parts subglobular.

Hypopygium ( Fig. 56 ) brown. Hypandrium with 2 strong bristles in apical part. Epandrium completely divided. Left epandrial lamella small, fused to hypandrium, with 2 fairly long bristles in apical part. Left surstylus with upper lobe ( Fig. 57 ) undivided, with markedly developed surstylar comb. Right surstylus ( Fig. 59 ) moderately large, sublinear, with excision on upper margin. Left cercus ( Fig. 58 ) mostly long, slender, divided into two lobes in apical part, lacking spines, with 1 long ventral and 2 similar left marginal bristles in basal part. Right cercus divided into lobes, lacking spines; left lobe long, broad; right lobe hardly prominent, rounded at apex. Phallus long, hair-like, curved.

Female. Unknown.

Measurements. – Body length 1.5 mm, wing length 1.2 mm.

Etymology. – The name refers to the region where it was first found.

Phylogenetic relationships. – The relationships of this species are unresolved beyond inclusion within the S. divergens group.

Distribution and seasonal occurrence. – Singapore. Found in one locality only, in December during the rainy season in Singapore.

Figures

Figs. 54-59. Stilpon malayensis, new species, male. 54, mid leg, anterior view, 55, wing, dorsal view, 56, hypopygium, ventral view, 57, upper lobe of left surstylus, dorsal view, 58, left cercus and subepandrial sclerite, right lateral view, 59, right surstylus, dorsal view. Scale bar: 0.1 mm.

Figs. 80-84. Details of male abdomen, dorsal view. 80, Stilpon lek, new species, 81, Stilpon lekkwar, new species, 82, Stilpon trilobatus, new species, 83, Stilpon malayensis, new species, 84, Stilpon paradoxus, new species; T – tergite. Scale bar: 0.1 mm.