Setostylus alienus L. PAPP, 2006

Papp, L., Merz, B. & Földvári, M., 2006, DIPTERA OF THAILAND A summary of the families and genera with references to the species representations, Acta Zoologica Academiae Scientiarum Hungaricae 52 (2), No. 2, pp. 97-269 : 136-137

Setostylus alienus L. PAPP , sp. n.

( Figs 32–33 )

Holotype male ( HNHM): THAILAND: Trang Prov., Thung Khai Botanic Garden , primary lowland rainforest, Nov 12, 2004, No. 28, leg. L. PAPP & M. FÖLDVÁRI.

Paratypes: Nov. 2004, leg. L. PAPP & M. FÖLDVÁRI: 4 m (one male’s abdomen with genitalia in a plastic microvial with glycerol): same data as for holotype; 5 m: ibid., Nov. 19, No. 38; 1 m: Trang Prov., Thung Khai Botanic Garden , along the “Nature Trail” , Nov 13, 2004, No. 29; 1 m: Khao Pu – Khao Ya N. P., along a forest brook below the (Pak Yam) waterfall, Nov 21, No. 42; 2 m: Trang Prov., Khao Chong Botanic Garden , rainforest, Nov. 22, No. 43 .

Measurements in mm: body length 3.67 (holotype), wing length 2.54 (holotype), 2.44–2.60 (paratypes), wing breadth 1.11 (holotype), 1.05–1.16 (paratypes).

Head and antennae all blackish brown, anterior ocellus minute. Preocellar frons strongly depressed, frontal tubercle less protruding. Flagellomeres with 8–10 macrochaetae on dorsal edge, no such setae on ventral edge of flagellomeres. Apical flagellomere cordiform (i.e. with asymmetrical blunt apex). Medial flagellomeres 4 times broader than long at middle.

Scutum yellow, no brownish pattern on it. Anepisternum and laterotergite brown, other pleura yellow (ochre in some individuals), antepronotum, proepisternum and proepimeron darker brown. Scutellum with brown apical 1/3, some medium long marginal and several shorter discal setae.

Fore coxa wholly yellow, apical 1/3 of mid coxa and hind coxa dark brown, as well as metanotum, otherwise yellow. Bases and apices of mid and hind femora brownish, legs otherwise yellow. Claws short and thick. Hind tibial spurs subequal, anterior spur of mid tibia 0.095 mm, ventral spur 0.26 mm long.

Wing light brown, veins brown. Cu2 rather long, apex well distal to base of M fork. A1 continued almost to wing margin, vein A2 almost to half distance to wing margin. Costal ratios (holotype): 0.71: 0.15: 0.45 mm, R4 0.21 mm. M1–2 stalk 0.21 mm, M1 1.17 mm.

Abdomen brown, tergite 1 black, anterior half of tergites 2 to 4 yellow with brown medial and caudal stripes; anterior ¾ of sternites 1 to 4 yellow. Tergite 9, gonocoxites and gonostyli yellowish. Male tergite 9 ( Fig. 33 ) similar to that of S. innotatus (EDWARDS) from Sumatra (cf. fig. 933 of Matile 1990). Also its gonostylus ( Fig. 32 ) is similar but medial spines shorter and thicker, apical process longer and thinner and apical seta slightly longer.

Etymology. Its specific epithet (“foreign”) refers to its peculiar combination of characters, but otherwise it is a true Setostylus sp.

S. alienus sp. n. does not key to any of couplet 3/ 4 in MATILE’ s (1990) for the Asian spp. of Setostylus : there are no ventral apical macrochaetae on flagellomeres but there are discal setae on scutellum. Contrarily to S. innotatus , its wings are unicolorous light brown, scutum of the new sp. unicolorous yellow. Details of male genitalia, particularly so for the shape and armature of gonostylus and apical part of gonocoxites give a safe basis for its identification.

Figures

Figs 29–33. 27–29 = Platyroptilon jarujini sp. n., holotype male: 29 = antenna (del. A. SZAPPANOS), 30 = tergite 9, 31 = gonostylus, subventral view.32–33 = Setostylus alienus sp. n., paratype male: 32 = gonocoxite and gonostylus, ventral view, 33 = tergite 9. Scales: 0.2 mm for Figs 30, 32–33, 0.1 mm