Schwenckfeldina lobocoxa, Sutou, Mitsuaki, 2005

Sutou, Mitsuaki, 2005, A new species of Schwenckfeldina (Diptera: Sciaridae) from Japan, Zootaxa 1087, pp. 59-64 : 60-62

Schwenckfeldina lobocoxa sp. n.

( Figs. 1 , 2 )

Male. Head: Prefrons with some setae in its lower half, clypeus bare. Scape and pedicel brown, almost as long as wide and weakly constricted basally, scape with long frontal setae and short setae, pedicel with many short setae mainly on its upper half; flagellomeres brown, 4th flagellomere ( Fig. 2 A) with rough surface, 1.35–1.62 (mean ± SD = 1.48 ± 0.06, n = 26; 1.39 in holotype) times as long as wide, hairs yellowish and fine, about 1/3 length of width of flagellomere, neck portion short. Palpifer without setae; palpus ( Fig. 2 B) yellowish brown, 3 segmented, its length ratio approximately 1.3:1.0:1.5, 1st segment with 7–13 setae mainly on its outside and with brownish sensory area bearing minute sensilla, 2nd segment nearly oval in shape with some setae on both outside and inside, 3rd segment slender with some setae.

Thorax: Color predominantly dark brown; mesonotum with dorsocentral setae of which posterior ones longer than anterior ones, and with long dorsolateral setae; scutellum with some setae, 5–7 of them longer than the others; posterior pronotum with setae. Coxae, femora, and tibiae predominantly brown, tarsi dark brown; each tibial vestiture with some differentiated spine­like short setae; fore tibial spur 1.0–1.2 times longer than width of tibial apex; tarsal claws untoothed. Wing ( Fig. 1 ) with brownish anterior veins and light brownish posterior veins; wing membrane and wing veins M, M1, M2, CuA, CuA1, and CuA2 without macrotrichia, distal 1/3–1/2 of R5 with both dorsal and ventral macrotrichia, x bare, y with 1–5 dorsal macrotrichia; length of R1 = 1.7–2.0R, CuA = 0.1–0.7x, x = 0.6–1.1y, c = 0.8w; R1 ending well beyond fork of M. Wing length 3.7–4.3 mm (mean ± SD = 4.04 ± 0.17, n = 25; 3.9 in holotype). Stalk of halter yellowish brown, knob brown with setae.

Abdomen: Tergites and sternites dark brown with many dark brownish setae, those on 1st and 2nd sternites sparser than those on posterior ones; membrane between tergites and sternites yellowish brown. Ventral surface of genitalia characteristic in having broad intercoxal membranous area ( Fig. 2 D, im) and 2 large dark brownish ventroapical lobes of gonocoxite ( Fig. 2 D, vl) being separated from each other or meeting at central axis; each ventroapical part of gonocoxite with differentiated long seta near junction to gonostylus; tegmen nearly trapezoidal in shape with sclerotized lateral margin; aedeagus distinct, distal branches as long as or longer than basal rod; parameral apodeme dark brownish, sclerotized, and mountain shaped forming about 60°angle; gonostylus ( Fig. 2 C) robust with broad base, slightly bending inward, characteristic 2 groups of megasetae ( Fig. 2 C, ms) located inside, lower group about 2.0–2.4 times longer than upper one.

Female. Same as male except genitalia and following characteristics: First flagellomere with several brownish setae among yellowish hairs; 4th flagellomere 1.62 (right) or 1.72 (left) times as long as wide. Scutellum with 9 long setae. Distal 2/3 of R5 with both dorsal and ventral macrotrichia; length of x = 0.5y. Wing length 5.9 mm (n = 1).

Specimens examined. Holotype: ɗ (NSMT­I­Dip­4457), JAPAN, Kawanishi, Obihiro city, Hokkaido, 42°51’N 143°11’E, 70 m a. s. l., 12–19.VI.1995, Malaise trap, leg. A. Ohkawa. Paratypes: 3ɗ (NSMT­I­Dip­4458­4460), same data as holotype except date, 1–6.VI.1995; 22ɗ 1Ψ (12ɗ 1Ψ, NSMT­I­Dip­4461­4473; 10ɗ, PCMS), same data as holotype.

Remarks. Schwenckfeldina lobocoxa sp. n. has the following unique characteristics in the male genitalia: broad intercoxal membranous area ( Fig. 2 D, im), large ventroapical lobe of the gonocoxite ( Fig. 2 D, vl), broad base of the gonostylus ( Fig. 2 C), and two groups of megasetae on the gonostylus ( Fig. 2 C, ms). The specific name of the new species is derived from one of these characteristics, the large ventroapical lobe of the gonocoxite. Based on these genitalia characteristics, I suggest that four Holarctic congeners are related to the new species: S. carbonaria ( Meigen 1830) , S. pectinea Menzel & Mohrig 1991 , S. imitans ( Johannsen 1912) , and S. dux ( Johannsen 1912) . Two Palaearctic species, S. impar ( Lengersdorf 1935) and S. explicata Mohrig & Mamaev 1982 , were described from the Far East of Russia, but their genitalia characteristics are quite different from those of the new species. Schwenckfeldina carbonaria is known from Europe, Russia, China, and Southeast Asia ( Gerbachevskaya­Pavluchenko 1986). However, Metzner & Menzel (1996) stated that the distribution of this species in Southeast Asia is doubtful. Menzel & Mohrig (2000) redescribed this species in detail with figures showing distinct differences from the new species in the narrow intercoxal membranous area, absence of the ventroapical lobe of the gonocoxite, and narrow base of the gonostylus. Schwenckfeldina pectinea , known from Europe, also differs from the new species in the small ventroapical lobe of the gonocoxite, narrow base of the gonostylus, and the short, sparse lower group of megasetae on the gonostylus. Schwenckfeldina imitans and S. dux are known from North America. They were originally described with figures by Johannsen (1912). Steffan (1974) redescribed these species and suggested that they are conspecific. These species differ from the new species in the narrow base of the gonostylus and short lower group of megasetae on the gonostylus. Furthermore, these Nearctic species have a blunt process nearly dorsad to the lower group of megasetae on the gonostylus, whereas the new species lacks this process. Taxonomic knowledge of this genus in the Southern Hemisphere is scarce. Further investigation in this region is needed.

Figures

FIGURE 1. Schwenckfeldina lobocoxa sp. n. (holotype), right wing. Scale: 1 mm.

FIGURE 2. Schwenckfeldina lobocoxa sp. n. (holotype). A, 4 th flagellomere; B, palpus; C, gonostylus, ventral view; D, genitalia, ventral view. Abbreviations: ae, aedeagus; gc, gonocoxite; gs, gonostylus; im, intercoxal membranous area; ms, groups of megasetae; pa, parameral apodeme; tg, tegmen; vl, ventroapical lobe of gonocoxite. Scale: 0.1 mm.