Melastrongygaster atrata Shima

Shima, Hiroshi, 2015, Melastrongygaster, a new genus of the tribe Strongygastrini (Diptera: Tachinidae), with five new species from Asia, Zootaxa 3904 (3), pp. 427-445 : 429-433

Melastrongygaster atrata Shima , sp. nov.

Figs. 1–10

Male. Head black, with grayish white pruinosity on fronto-orbital plate, parafacial and upper face, the pruinosity shifting in appearance from dark gray to silvery gray with direction of light; inner margin of fronto-orbital plate inside row of frontal setae shining black; lower face, lower occiput and genal dilation with dark grayish pruinosity; frontal vitta matte dark brown; lunule black; upper occiput black; antenna dark brown to black; palpus black. Frons strongly narrowed above, at the narrowest point about 2 times as wide as base of arista, in profile about 2 times as long as face; frontal vitta almost linear in front of ocellar triangle and strongly widened anteriorly; parafacial weakly narrowed below, about 1.3 times as wide as (nearly as wide as in profile) 1st flagellomere at middle height; face weakly concave, very weakly carinate on upper median portion between base of antenna, lower portion very weakly but sharply warped forward; gena about 2/5 (about 1/ 4 in profile) as high as eye height; occiput only weakly bulged. Inner vertical setae fine and long, crossed and weakly directed forward, 1/3–2/5 as long as eye height; ocellar seta fine hair-like, about 1/2 as long as inner vertical seta; 12–16 fine frontal setae, upper setae finer and shorter, lowest seta nearly level with base of antenna; fronto-orbital plate without hairs except fine short hairs among row of frontal setae; parafacial bare; facial ridge with 2–3 long and some short and fine setae on lower 1/4; 4–6 long and strong subvibrissal setae; postocular setae close to posterior eye margin, long and directed forward on upper 1/2. Base of antenna nearly level with lower 1/3 of eye height; antenna short, at most 4/5 as long as face; pedicel with a long seta which is nearly as long as entire antenna; 1st flagellomere about 1.5 times as long as wide and 1.5 times as long as pedicel; arista about 1.5 times as long as pedicel and 1st flagellomere together, thickened on basal 1/5–1/6, 2nd aristomere shorter than wide. Prementum about 3/4 as long as gena; palpus about 2 times as long as 1st flagellomere.

Thorax shining black in ground color, with very thin grayish pruinosity on postpronotal lobe, presutural area of scutum and proepimeron. Hairs black, rather sparse short and erect on scutum, long and erect on scutellum and dense and long on pleura; 1–2 presutural acrostichal setae, if 2 setae present, then anterior seta fine; 2–3 presutural dorsocentral setae, if 3 setae present, then 1st seta fine and situated lateral to line of 2nd and 3rd setae; 2–3 katepisternal setae, if 3 setae present, then lower seta fine; basal scutellar seta about 1.5 times as long as scutellum and almost subequal in length to apical seta; subapical scutellar setae about 2 times as long as scutellum; apical scutellar setae crossed and suberect; discal scutellar setae fine, situated close to posterior margin, slightly longer than scutellum.

Wing hyaline, weakly tinged with pale brown, sometimes more strongly tinged on basal portion and along vein R2+3; tegula and basicosta black; lower calypter pale brownish, inner margin close to scutum dark brown, fringe short. Costagial setae rather short, not reaching to humeral crossvein; base of vein R4+5 with 2–3 fine setulae dorsally and ventrally, rarely without them. Relative lengths of costal sectors 2nd, 3rd and 4th approximately as 1:3.5:1; vein M from dm-cu crossvein to its bend about 2 times distance between the bend and wing margin; dm-cu crossvein curved in weak S-form; last section of vein CuA1 about 2/5 as long as dm-cu crossvein.

Legs shining black, femora with very thin grayish pruinosity; 5th tarsomeres with dull grayish brown pruinosity; pulvilli pale yellowish brown. Fore tibia with 2 posterior setae; mid tibia with 1 anterodorsal, 3–4 posterodorsal, 1 posteroventral and 1 ventral setae; hind tibia with 3 anterodorsal, 4–5 posterodorsal and 2 ventral setae; 5th tarsomere rather long, slightly less than 1/2 of 1st tarsomere in fore leg; claws and pulvilli nearly as long as 5th tarsomere.

Abdomen shining black, with thin grayish pruinosity on dorsum of anterior 1/2–2/5 of 3rd tergite, still thinner pruinosity on anterior 1/2 of 4th and very thin on entire 5th. Hairs dense fine and black, rather short on dorsum and long on sides and venter; syntergite 1+2 with 1 pair of long median discal, some pairs of lateral discal, 1–2 pairs each of long and strong median marginal and long lateral marginal setae; 3rd tergite with 2 pairs or 5 long irregularly set discal and a row of strong marginal setae; 4th tergite with rather irregularly set row of long discal and a regular row of long marginal setae; 5th tergite with an irregularly set row of rather fine discal and a row of rather fine marginal setae; 2nd to 4th sternites each with dense long hairs on marginal and posterior portion.

Male terminalia: Epandrium with 2 pairs of strong setae; surstylus weakly narrowed from base to apex in lateral view, with sparse fine hairs on outer wall and very dense fine short pile on inner wall; bacilliform sclerite indistinct; postgonite nearly comma-like in lateral view, apex pointed, without hair; cerci in dorsal view widely and roundly excavated on anterior margin, narrow on posterior 1/3, very narrowly separated on apical 2/5, in lateral view broad basally and narrowed to apex, weakly curved ventrally.

Female. Differing from male as follows: Frons wide, vertex 0.28–0.29 of head width; fronto-orbital plate shining black from vertex to level of base of 1st flagellomere, grayish, somewhat silvery, pruinosity on narrow oblique outer portion of anterior 2/5 of fronto-orbital plate along eye margin to parafacial; frontal vitta weakly widened anteriorly, nearly as wide as fronto-orbital plate at middle or slightly narrower; inner vertical setae strong and converging apically, about 3/5 as long as eye height; outer vertical seta developed, about 2/3 as long as inner seta; ocellar seta short but distinct, 1/2–1/3 as long as inner vertical seta; 1 outwardly directed prevertical seta, slightly longer than ocellar seta; 2 subequally long proclinate orbital setae slightly longer than prevertical seta; 7–9 strong frontal setae, all subequal in length to proclinate orbital setae; fronto-orbital plate with very sparse fine short hairs on inner 1/3; facial ridge with several strong setae on lower 1/3; gena slightly wider, about 4/9 (about 1/ 3 in profile) of eye height, with sparser and stronger hairs; postocular setae shorter. Wing with distinct brownish tinge on anterior 1/3 along veins R2+3 and R4+5. Legs shining black; 3rd to 5th tarsomeres shorter and widened, 5th tarsomere of fore leg only slightly longer than wide; claws and pulvilli shorter than 5th tarsomere. Abdomen almost shining black, at most with very thin pruinosity on dorsum of anterior portion of 3rd and 4th tergites; hairs on dorsum short fine suberect and rather sparse, sternites with short recumbent hairs; syntergite 1+2 with a pair each of median discal, lateral discal, median marginal and lateral marginal setae; 3rd tergite with 2 pairs of median discal, 1 pair of lateral discal and a row of marginal setae; 4th tergite with 1–2 pairs of median discal and a row of marginal setae. Female terminalia: Sixth tergite entire, nearly cylindrical, with a row of rather long and strong hairs on posterior margin, 6th and 7th spiracles on mid ventral portion of 6th tergite; 6th sternite slightly shorter than 5th sternite; 7th tergite entire, with a few hairs on posteroventral margin; 7th sternite forked on posterior 2/5, with fine hairs; 8th tergite indistinct; 8th sternite strongly sclerotized, strongly curved ventrally on apical 1/2 and sharpened to apex, with median groove, basal portion of 8th sternite concealed under 7th tergite and exposed on apical portion.

Body length: 7.3–8 mm.

Holotype male, Moiwayama, Sapporo, Hokkaido, Japan, 2.vi.1968, T. Kocha ( EIHU).

Paratypes: Japan: 3 males, same data as holotype ( EIHU, KUM); 1 female, Shigiuchi, Nasushiobara, Tochigi, Honshu, 14–21.v.2010, Malaise trap, T. Matsumura; 1 male, Mt. Kanetsukido, Yorii, Saitama, Honshu, 16.iv.2004, K. Hara; 1 male, Yotsuyama-shrine, Ogano, Saitama, 26.iv.1993, K. Hara; 1 male, Mikashima, Tokorozawa City, Saitama, Honshu, 12.iv.1990, H. Mitsui; 1 female, Fukiage, Imperial Palace, Tokyo, 6–13.iv.2010, Malaise trap, M. Owada; 3 males 1 female, Yurano, Kumakogen, Ehime, Shikoku, 20.iv.2007, Malaise trap, E. Yamamoto; 1 male, Mt. Kasatori, Odamiyama, Ehime, Shikoku, 18.v.1997, E. Yamamoto (all in KUM). South Korea: 1 male, Samgak- Koji, 1000-1300 m, Macheon-myeon, Gyeongsangnam-do, 11.v.1991, T. Saigusa ( BLKU).

Etymology. This species is named due to its dark body color.

Distribution. Japan (Hokkaido, Honshu, Shikoku), South Korea.

Remarks. In the male terminalia, this species resembles the following species, M. chaoi , but the cerci of M. atrata are more closely associated near middle for long distance and the surstylus is narrower with dense short pile on the inner wall. The epandrium bears only 2 pairs of strong setae in this species. This species appears in the spring to early summer and is distributed in the northernmost area among members of this genus.

Figures

FIGURES 1 – 4. Habitus of adult Melastrongygaster atrata sp. nov. 1. Male in lateral view. 2. Male head in lateral view. 3. Male head and thorax in dorsal view. 4. Female head in dorsal view.

FIGURES 5 – 8. Male terminalia of Melastrongygaster atrata sp. nov. 5. Epandrium, surstylus and cerci in dorsal view (hairs on epandrium, surstylus and left cerci omitted) 6. Same in lateral view (hairs on epandrium omitted) 7. Hypandrium, postgonite and phallus in lateral view. Scale: 0.15 mm. 8. 5 th. sternite in ventral view (hairs on left side omitted). Scale: 0.25 mm.

FIGURES 9 – 10. Female terminalia of Melastrongygaster atrata sp. nov. 9. Lateral view. 10. Ventral view. Scale: 0.1 mm.