Scorpiurus thorpei, Masunaga, 2017

Masunaga, Kazuhiro, 2017, Saltmarsh flies of the genus Scorpiurus Parent from New Zealand (Insecta: Diptera: Dolichopodidae), Zootaxa 4324 (3), pp. 581-591 : 589-591

Scorpiurus thorpei sp. nov.

( Figs 3B , 4C–D , 7 )

Diagnosis. Body length 3.3–4.5 mm, 1 st flagellomere of antenna 2.1 times as long as its basal thickness, proboscis 0.6 times as long as eye height, scutellum with 4 long setae, acrostichal setae biserial, with 7–12 in each row, but none on flat area in front of scutellum, posterior abdominal segments almost straight in male, legs pale brown except for coxae and basal part of femora, these being concolorous with pleura.

Description. Male ( Fig. 3B ). Head 1.9 times as high as long, 0.9 times as wide as high. Frons wide, metallic green with grayish brown pollinosity; frontal bristle 0.8 times as long as ocellar bristle. Ocellar tubercle distinct, with 2 strong ocellar bristles and 2 minute postocellar setae. Occiput metallic green with grayish pollinosity. Postocular ciliation uniserial, erect, black. Postgena with many long, white setae. Face and palpus brown with grayish brown pollinosity, tinged with green. Face at narrowest part 0.1 times as wide as head. Palpus 2.4 times as long as wide, clothed with long setae. Proboscis 0.6 times as long as eye height. Antenna black; scape 1.8 times as long as deep, with several setae on inner side at middle; pedicel 1.1 times as long as deep; 1 st flagellomere 2.1 times as long as basal thickness, with several setulae on inner surface; arista apical, 1.6 times as long as 1 st flagellomere . Thorax. Mesonotum metallic green in ground color, with grayish white pollinosity. Thoracic bristles black. Chaetotaxy: acrostichals (ac) well developed, biserial, 7–12 in each row, absent on flat area in front of scutellum; dorsocentrals (dc) biserial, with 7 long setae in each low, 7th dc longest; postpronotum with 1 long seta and 1–3 short setae; 1 each of posthumeral, presutural, sutural, postsutural, supra-alar, and postalar setae; notopleuron with 2 setae. Proepisternum with 2 setal clusters on upper and lower parts, each consisting of 5–8 long, white setae. Scutellum with 2 pairs of strong marginal bristles. Legs. Coxae and basal parts of femora concolorous with pleura, other parts of legs pale brown. Foreleg. Coxa 2.5 times as long as thick, with many long, white setae densely arrayed on anterior surface. Femur 5.8 times as long as thick, 1.2 times as long as tibia, tapered gradually toward apical 2/3, with erect anterodorsal seta on subapex, row of long posterodorsal and posterior setae, and long, white ventral setae on basal 1/3. Tibia 1.9 times as long as first tarsomere, with 2 pairs of erect setae on basal basal 1/3 and 2/3, one of each pair directed dorsally, the other posterodorsally, and circlet of strong apical setae. First tarsomere with 2 long setae basally, of which more basal one shorter. Tarsomeres simple; relative lengths of tarsomeres 1–5 35:15:10:9:10. Midleg. Coxa with row of long, white setae on anterior surface and conspicuous strong, black seta near base of coxa. Trochanter with 2 long anterior setae and 2 short dorsal setae on apical margin. Femur as long as tibia, with long white ventral setae near base and 2 strong anteroventral and posteroventral subapical setae. Tibia with 2 pairs of erect setae on basal 1/3 and 2/3, one of each pair directed anterodorsally, the other and posterodorsally, and circlet of strong apical setae. Tarsomeres simple, their relative lengths 39:15:11:9:10. Hindleg. Coxa with conspicuous outer seta on basal 2/5 and some white setae on apical margin. Trochanter with 1 anterodorsal and 1 dorsal seta on apical margin. Femur 0.9 times as long as tibia, with strong row of anterodorsal and posterodorsal setae. Tibia with 3 pairs of erect setae on basal 1/5, 1/3 and 2/3, one of each pair directed anterodorsally, the other posterodorsally; circlet of strong apical setae present, of which posterodorsal seta longest. Tarsomeres simple, their relative lengths 28:14:12:8:10. Wing ( Fig. 4C ). Long, narrow, and darkened. Apical section of CuA1 1.4 times as long as crossvein dm-cu. Calypter pale brown with pale brown fringe. Halter yellowish brown. Abdomen. Abdominal terga tinged strongly green with grayish pollinosity and with short, black setae. Hypopygium large and rectangular. Cercus long and arrowhead-shaped with long, black setae on ventral margin and long, white curved setae on inner side of ventral margin ( Fig. 7 ). Body length 3.2–4.1 mm; wing length 3.9–4.1 mm.

Female. Face at narrowest part 0.2 times as wide as head. Proboscis 0.6 times as long as eye height. Relative lengths of tarsomeres 1–5 of foreleg 35:14:11:7:9, those of midleg 36:14:12:8:10, and those of hindleg 27:15:12:9:10. Wing: apical section of CuA1 1.2 times as long as crossvein dm-cu ( Fig. 4D ). Body length 3.1–4.5 mm; wing length 3.6–4.5 mm.

Material examined. HOLOTYPE: ♂. 3 km, W of Linkwater, South Island , 7.xii.2007, K. Masunaga leg. ( NZAC) . Holotype No. D-1001. PARATYPES: New Zealand: 4♂, 5♀, Ak., Tamaki Tahuna Torea Res., upper intertidal mud, 3.i.2006, SE Thorpe ( NZAC) ; 2♂, 7♀, Glendowie, Auckland, North Island , 7.iii.2007, S.E. Thorpe & K. Masunaga leg. ( NZAC, LBM) ; 23♂, 130♀, Glendowie, Auckland, North Island , 7.iii.2007, K. Masunaga leg. ( NZAC, LBM) ; 187♂, 92♀, Glendowie, Auckland, North Island , 29.xi.2007, K. Masunaga leg. ( NZAC, LBM) ; 19♂, 19♀, Te Atatu Peninsula, Auckland, North Island , 30.xi.2007, K. Masunaga leg. ( NZAC, LBM) ; 12♂, 13♀, Favona, Auckland, North Island , 30.xi.2007, K. Masunaga leg. ( NZAC, LBM) ; 27♂, 37♀, Te Atatu Peninsula, Auckland, North Island , 1.xii.2007, K. Masunaga leg. ( NZAC, LBM) ; 14♂, 31♀, Browns Bay, North Island , 5.xii.2007, K. Masunaga leg. ( NZAC, LBM) ; 451♂, 56♀, 3 km, W of Linkwater, South Island , 6.xii.2007, K. Masunaga leg. ( NZAC, LBM) ; 129♂, 268♀, 3 km, W of Linkwater, South Island , 7.xii.2007, K. Masunaga leg. ( NZAC, LBM) .

Distribution. New Zealand (North Is., South Is.) ( Fig. 1 )

Etymology. The species is named in honor of Mr. Stephen E. Thorpe (Auckland), who cooperated with me in collecting it.

Remarks. Externally, this new species is similar to Scorpiurus aenescens , but S. thorpei sp. nov. differs in having legs that are pale brown except for the coxae and the basal parts of the femora, almost straight posterior abdominal segments in the male and thus no scorpion-like appearance, and strongly green-tinged abdominal terga.

Both species inhabit the same kind of environment ( Fig. 2A–B ). As with S. aenescens , to collect many specimens of S. thorpei sp. nov. it was necessary to sweep the reeds on which the flies were resting.

Figures

FIGURE 1. Map of sampling sites.

FIGURE 2. Habitat of the genus Scorpiurus. A, Landscape of the sampling site. Near Linkwater, South Island, New Zealand; B, Enlarged view of habitat.

FIGURE 3. Adult males of Scorpiurus spp. A, S. aenescens; B, S. thorpei sp. nov.

FIGURE 4. Wings of Scorpiurus spp. A, S. aenescens ♂; B, S. aenescens ♀; C, S. thorpei sp. nov. ♂; D, S. thorpei sp. nov. ♀. Scale bars = 1 mm.

FIGURE 7. Scorpiurus thorpei sp. nov., male. Hypopygium in lateral view. Scale bar = 1 mm.