Trichoformosomyia abbreviata, Tachi, Takuji, 2013

Tachi, Takuji, 2013, A new species of the genus Trichoformosomyia Townsend from Malaysia (Diptera: Tachinidae), Zootaxa 3702 (1), pp. 61-70 : 62-68

Genus Trichoformosomyia Baranov

Trichoformosomyia Baranov, 1934: 163 . Type species: T. sauteri Baranov, 1934 , by original designation. Malaisimyia Mesnil, 1953: 146 . Type species: M. flavicoxa Mesnil , by monotypy.

Description. Head (Figs. 1, 2). Vertex narrow, distinctly narrower in male than in female; inner vertical setae weak and parallel to each other in male, strong and crossing each other in female; outer vertical setae about 2/3 as long as inner vertical setae in female, very weak or absent in male; ocellar setae weak and fine; reclinate orbital seta present, 1 in male, 2 in female; 2 proclinate orbital setae present in female, absent in male; 7–10 frontal setae reaching level of upper margin of scape; parafacial and facial ridge bare; lower facial margin produced forwards beyond vibrissal angle; vibrissa at level of lower facial margin; upper occiput flattened; postgena bulged with some fine setae; compound eye densely setulose. Antenna with pedicel having 1 rather long seta; first flagellomere 3–4 times as long as wide; arista pubescent; 1st aristomere shorter than wide; 2nd aristomere as long as wide; 3rd aristomere thickened at most on basal 1/3; palpus slender, subequal in length to first flagellomere; prementum approximately 4 times as long as wide; labella pad-like.

Thorax. Scutum black in ground color, with grayish white pruinosity; pleura dark brown or black in ground color, with densely grayish white pruinosity; prosternum with several setae on each side; proepisternum bare; proepimeral seta strong; 2 postpronotal setae; 1 presutural and 1 postsutural acrostichal setae; 2 presutural and 3 postsutural dorsocentral setae; 1 presutural and 3 postsutural intra-alar setae; 3 supra-alar setae, anterior seta shorter than 1st postsutural intra-alar seta; 2 notopleural setae; upper part of anepisternum with 1 strong seta anterior to row of anepisternal setae; 3 katepisternal setae; anepimeron with some setae; katepimeron and anatergite bare; scutellum with 3 pairs of marginal setae (basal, subapical and apical setae), subapical setae widely separated basally, distance between their bases greater than that between a subapical and its corresponding basal seta, apical setae strong and crossed horizontally.

Wing. Pale brown hyaline, more brownish on apical anterior margin; tegula and basicosta black; lower calypter light brown; halter light yellow. First and 2nd costal sectors with long or short setae ventrally; vein R4+5 with 1 seta dorsally on basal part and several long setae ventrally; vein M curved at obtuse angle, its bend closer to wing margin than to crossvein dm-cu; vein A1+ CuA2 not reaching wing margin.

Legs. Fore coxa bare on anteroventral surface; fore tibia with 1 preapical dorsal, 1 preapical posterodorsal, 1 preapical posteroventral and 1 posterior setae; mid tibia with 1 anterodorsal, 2–3 posterodorsal and 1 ventral setae; hind tibia with 3 preapical dorsal and 1 apical anteroventral setae; claws subequal in length to that of 5th tarsomere in male, shorter in female.

Abdomen. Excavation of syntergite 1+2 not reaching hind margin; 3rd and 4th tergites with or without median discal setae; 2nd to 4th sternites usually with a pair of long and some short setae on posterior margin.

Male postabdomen ( Figs. 3–10 ). Surstylus fused with epandrium at base; cerci fused completely and strongly constricted laterally on apical 1/ 4 in dorsal view, apex claw-shaped in lateral view; pregonite fused with hypandrium basally; postgonite slender and elongate; epiphallus absent; phallus with a plate medially in lateral view.

Female postabdomen ( Fig. 11 ). Fifth sternite elongate with some long setae on posterior margin; 6th tergite of small rectangular hemitergites; 6th sternite trapezoid in shape with some fine setulae on posterior margin; 7th tergite of small hemitergites; 7th sternite small trapezoid-shaped with some fine setulae on posterior margin; 8th tergite of short and longitudinal hemitergites; 8th sternite present with some fine setulae; epiproct absent; spiracles of 6th and 7th segments both present on or nearby each tergite.

Remarks. The genus Trichoformosomyia comprises three species distributed in East Asia and the Oriental Region ( Fig. 16 ) and is characterized by the following combination of characters in the external morphology among Tachininae (Crosskey 1976; Tschorsnig 1985): eye setulose; 2 presutural and 3 postsutural dorsocentral setae; scutellum with 3 pairs of marginal setae; 2 subapical scutellar setae widely separated basally, distance between their bases much greater than that between a subapical seta and its corresponding basal seta; tegula and basicosta blackish brown. Crosskey (1976) and Tschorsnig (1985) tentatively placed this genus in the Leskiini based on its similarities with members of this tribe. Shima (1983) commented that this genus appears to be excluded from the Leskiini due to its peculiar male and female postabdominal character states.

It has not been possible to resolve the tribal placement of Trichoformosomyia during this study. I therefore follow the views of Crosskey (1976) and Tschorsnig (1985) in tentatively placing this genus in the Leskiini .

The monophyly of Trichoformosomyia has been reevaluated based on the examination of male and female postabdominal characters. The surstylus is fused with the epandrium at its base in all three species of this genus, but this state is considered to have occurred many times because it is recognized in different members of the Tachininae (e.g., tribe Tachinini , in Pseudoebenia Shima, Han & Tachi (tribe Macquartiini ) and in some species of Ceromya Robineau-Desvoidy (tribe Siphonini )). The male cerci in Trichoformosomyia are completely fused and the apex is strongly curved and claw-like in lateral view. Although the fusion of male cerci is also often found in some genera such as Solieria Robineau-Desvoidy (tribe Leskiini ) and Exorista Meigen (tribe Exoristini ), the clawlike apex is unique among members of the family Tachinidae because it is strongly constricted laterally ( Fig. 4 ). As mentioned by Tschorsnig (1985), the features of the phallus are unique to members of this tribe ( Figs. 6 , 10 ). Additionally, there are several strong setae along the posterior margin of the 5th abdominal sternite in the female of T. sauteri ( Fig. 11 ). The last character state might be specific to this genus, although females of the other two species were unavailable for study. Consequently, I consider the monophyly of this genus to be supported by the following autapomorphies in the male and female postabdomen: apex of male cerci claw-like; phallus with a plate medially in lateral view; female 5th sternite with several strong setae on posterior margin.

Trichoformosomyia abbreviata sp. nov. (Figs. 1, 3–6, 12, 14, 16)

Diagnosis. Male wing ventrally with short setae on 1st and 2nd costal sectors and 1–3 rather long setae at base of vein R4+5; 3rd and 4th abdominal tergites without median discal setae.

Description. Male. Head with white pruinosity on face; fronto-orbital plate and parafacial silvery white pruinose; gena with slightly yellowish white pruinosity; scape, pedicel, basal half of first flagellomere and palpus light yellow; arista and apical half of first flagellomere dark brown. Vertex about 1/14 of head width; frontal vitta strongly narrowed, scarcely seen when observed from above; width of parafacial at middle about twice as wide as palpus; gena about 1/10 of eye height; lower facial margin strongly produced forwards. Inner vertical setae slightly longer than frontal setae; ocellar seta weak and rather short; 1 reclinate orbital seta, subequal in length to inner vertical seta. Seven to 10 frontal setae, lowest seta nearly level with upper margin of scape; vibrissa nearly at level of lower facial margin; occiput with a row of black setae behind postocular setae; postgena rather developed with many white fine setae. Antenna falling short of lower facial margin; first flagellomere 3.5–4 times as long as wide, about 4 times as long as pedicel; arista pubescent, longest hairs longer than basal width of arista, thickened on basal 1/5–1/3; prementum about 4 times as long as wide.

Thorax. Black in ground color, with 4 longitudinal black stripes and grayish white pruinosity on presutural area of scutum; pleura dark brown or black in ground color, with densely grayish white pruinosity; 1 pre- and 1 postsutural acrostichal setae; 2 pre- and 3 postsutural dorsocentral setae; 1 pre- and 3 postsutural intra-alar setae; 3 katepisternal setae, lower seta shorter than upper anterior one.

Wing. First and 2nd costal sectors with short setae ventrally; vein R4+5 with 1 seta dorsally at base and 1–3 rather long setae ventrally; 2nd costal sector 2.1–2.3 times as long as 3rd and 0.6–0.8 times as long as 4th.

Legs. Coxae and trochanters light yellow; femora, tibiae and tarsi black. Fore tibia with 1 posterior seta; mid tibia with 1 anterodorsal, 2–3 posterodorsal and 1 ventral setae; hind tibia with 3 preapical dorsal setae; claws subequal in length to that of 5th tarsomere.

Abdomen. Yellow on syntergite 1+2, anterior 2/3–4/5 of 3rd tergite and 1/3–1/2 of 4th tergite; black on posterior 1/3–1/5 of 3rd tergite and 1/2–2/3 of 4th tergite; 5th tergite black with grayish white pruinosity on anterior 1/2. Syntergite 1+2 with excavation not reaching its hind margin; 3rd and 4th tergites without median discal setae; 5th sternite nearly rectangular in ventral view.

Male postabdomen. Surstylus fused with epandrium at base, slightly curved dorsally at middle in lateral view; apical part of cerci claw-shaped and strongly curved dorsally in lateral view; hypandrial arms not fused with each other; pregonite fused with hypandrium basally, curved ventrally at middle; postgonite slender and elongate; epiphallus absent; phallus with a plate medially in lateral view.

Female. Unknown.

Body length. 8–10 mm.

Holotype male, Malaysia, Sabah [Borneo], Crocker Range, Inobong, 2.v.2004, T. Tachi (ITBC).

Paratypes. MALAYSIA [Borneo], 4 males, same data as holotype; 6 males, same locality as holotype, 4.ii.2004, 16.iv.2004, Tachi & Shima (ITBC, BLKU).

Etymology. This species is named for the short setae on the underside of the costa of the wing.

Distribution. Malaysia (Sabah).

Host. Unknown.

Remarks. Males of the other two known species of Trichoformosomyia have many long setae on the ventral side of the 1st and 2nd costal sectors of the wing (Fig. 15). However, the male of this new species has only short setae on the ventral side of these costal sectors (Fig. 14). In addition, it has only 1–3 long setae on the ventral side of R4+5, in contrast to the other species having many long setae. Consequently, this species is easily distinguishable from the other species by these features of the wing. The male postabdomen is, on the other hand, similar to that in the other species: cerci completely fused and apex claw-shaped; surstylus fused with epandrium at base; postgonite slender and elongate; phallus with a plate medially in lateral view. This species is, therefore, assigned to Trichoformosomyia based on the male postabdominal characters and differs from T. sauteri in having the following male postabdominal character states: fifth abdominal sternite nearly rectangular in ventral view; surstylus slightly curved dorsally at middle in lateral view.

Trichoformosomyia sauteri Baranov (Figs. 2, 7–11, 13, 15–16)

Trichoformosomyia sauteri Baranov, 1934: 163 . Lectotype male (DEI, not examined), by designation of Sabrosky & Crosskey (1969: 53). Type locality: Taiwan.

Malaisimyia flavicoxa Mesnil, 1953: 146 . Holotype male (FMNHH, not examined). Type locality: Myanmar, Kambaiti.

Diagnosis. Similar to T. abbreviata but differing as follows: abdomen with a longitudinal black stripe on middorsal portion on syntergite 1+2 to 4th tergite; coxae brownish black or dark brown with grayish white pruinosity; male wing with many long setae on ventral side of 1st and 2nd costal sectors and on vein R4+5 from its base to r-m crossvein.

Redescription. Male. Frontal vitta black; antenna with first flagellomere dark brown to black; wing pale brown hyaline, slightly brownish on apical anterior margin; coxae brownish black or dark brown with grayish white pruinosity; abdomen back on mid-dorsal longitudinal portion on syntergite 1+2 to 4th tergite. Vertex 1/10–1/12 of head width; frontal vitta widened anteriorly; parafacial about as wide as width of palpus at middle; gena 1/16–1/13 of eye height; 10–12 frontal setae; antenna with first flagellomere 3–3.5 times as long as wide; 1st and 2nd costal sectors with 2 very long setae proximal to its break behind humeral crossvein and many rather long setae ventrally; vein R4+5 with 5–8 long setae ventrally from base beyond middle of crossvein r-m, apices curved posteriorly; 2nd costal sector 1.9–2.1 times as long as 3rd and 0.5–0.7 times as long as 4th; 5th abdominal sternite nearly square in ventral view. Male postabdomen: surstylus nearly straight in lateral view; cerci slightly curved dorsally on basal 1/ 4 in lateral view, slightly wide basally in dorsal view.

Female. Similar to male, but differing as follows: vertex 1/6–2/11 of head width; frontal vitta twice as wide as fronto-orbital plate at middle; gena 1/12–1/11 of eye height; outer vertical seta present, subequal in length to posterior reclinate orbital seta; 2 proclinate and 2 reclinate orbital setae; first flagellomere about 4 times as long as wide; apical anterior margin of wing more brownish; 1st and 2nd costal sectors of wing with many fine setae ventrally; vein R4+5 with 3–6 short setae ventrally from base to middle of crossvein r-m; claws shorter than 5th tarsomere; anterior 1/4–1/3 of 4th abdominal tergite yellow with silvery white pruinosity. Female postabdomen: 5th sternite elongate with some long setae; 6th tergite of small rectangular hemitergites in lateral view; 6th sternite trapezoid in shape with some fine setulae on posterior margin, apex curved ventrally at middle; 7th tergite of small hemitergites, shorter than 6th hemitergite; 7th sternite small trapezoid-shaped with some fine setulae on posterior margin; 8th tergite of short and longitudinal hemitergites; 8th sternite present with some fine setulae; epiproct absent; spiracles of 6th and 7th segments present on anteroventral portion of 6th hemitergite and on membrane below 7th hemitergite, respectively.

Body length. 6.5–9.6 mm

Specimens examined. JAPAN • 1 male, Honshu, Moroyama, Saitama Prefecture, 6.ix.1975. CHINA. 2 males, 1 female, Sichuan, Tianquan Xian, Dayuxi, 1200m, 30, 31.viii.1993. TAIWAN [Nantou-hs.]. 3 males, 3 females, Meichi, Jenai-hsiang, Tungyenchi, 950 m, 19.xi.1997. 3 males, Nanshanchi, 31.iii.1996. 1 male, Guanin, Puhbuh, 700m, Shytzyytour, Puuli, 16.vi.1999. 1 male, Kanshirei, 6.vi.1965. VIETNAM. 4 males, Langbian, 1650m, Da Lat Nui, Lam Dong, Prov., 10–11.xi.2000. 1 male, nr. Sapa Deo Tram Ton, 1950m, Lao Cai Prov., 27–29.vi.1997. 2 males, Sa Pa, 1700m, Lao Cai Prov., 26, 30.v.1997 (all in BLKU).

Distribution. Japan (Honshu)*, Russia (S. Far East), China (Sichuan)*, Taiwan, Vietnam, Myanmar.

Host. Unknown.

Trichoformosomyia notata Richter

Trichoformosomyia notata Richter, 1999: 721 . Holotype male (ZIN, not examined). Type locality: Russia, Far East, vicinity of Khabarovsk.

Distribution. Russia (Far East).

Remarks. Since specimens of the species were not available for study, relationships among the species of this genus remain unclear. Based on the original description of this species, it is distinguished from the other species of Trichoformosomyia by having a pair of median discal setae on the 3rd and 4th abdominal tergites in the male.

Key to species of Trichoformosomyia

1. Abdomen with a longitudinal black stripe on mid-dorsal portion of syntergite 1+2 to 4th tergite; male wing ventrally with many long setae on 1st and 2nd costal sectors and at base of R4+5 (Fig. 15)......................................... 2

- Abdomen without a longitudinal black stripe on mid-dorsal portion; male wing ventrally with short setae on 1st and 2nd costal sectors and 1–3 rather long setae at base of R4+5 (Fig. 14)...................................... T. abbreviata sp. nov.

2. Third and 4th abdominal tergites without median discal setae..................................... T. sauteri Baranov

- Third and 4th abdominal tergites each with one pair of median discal setae........................... T. notata Richter

Figures

FIGURES 16. Known distributions of Trichoformosomyia species. Black star: T. abbreviata sp. nov.; black square: T. notata Richter; black circles: T. sauteri Baranov.

FIGURES 3 – 6. Male postabdomen of T. abbreviata sp. nov. (paratype). 3. Epandrium, cerci and surstylus in lateral view. 4. Same in dorsal view (setae omitted on left side). 5. Fifth abdominal sternite in ventral view (setae omitted on the left side). 6. Hypandrium, pregonite, postgonite and phallus in lateral view. Scale bars = 0.2 mm. (Abbreviations: cerc, cerci; distph, phallus; epand, epandrium; hypd, hypandrium; pgt, postgonite; prgt, pregonite; sur, surstylus).

FIGURES 7 – 11. Male and female postabdomen of T. sauteri Baranov (Taiwan). 7. Epandrium, cerci and surstylus in lateral view. 8. Same in dorsal view (setae omitted on left side). 9. Fifth abdominal sternite in ventral view (setae omitted on the left side). 10. Hypandrium, pregonite, postgonite and phallus in lateral view. 11. Female postabdomen in lateral view. Scale bars = 0.2 mm. (Abbreviations: st 5, 5 th abdominal sternite; st 6, 6 th abdominal sternite; st 7, 7 th abdominal sternite; t 6, 6 th abdominal tergite; t 7, 7 th abdominal tergite).