Six new species of the genus Dicranosepsis Duda (Diptera, Sepsidae) from Vietnam, with a revised key to the species

Male. Head: frons black and shiny; almost all face dark brown to black; facial orbit dark brown; gena and occiput black and thinly pruinose; antennal segments entirely black, pubescent; arista black and bare; vibrissal angle with 3 moderately developed setae; genal margin with at least 10 peristomal setae in a row and a strong seta at genal angle; 1 oc, 1 vti, 1 vte, 1 pvt; or absent.

Thorax: wholly black; mesonotum, scutellum, and postpronotal lobe thinly pruinose: proepisternum thinly pruinose; anepisternum glossy; katepisternum anteroventrally shining and posterodorsally pruinose; anepimeron anteriorly shining and posteriorly pruinose; meron thinly pruinose; katatergite and metanotum thinly pruinose, central part of metanotum shining; 1 pprn, 2 npl, 2 dc, 1 sa, 1 pa, 1 m, 1 sc. Wing: hyaline, slightly tinged with brown and without dark spot near apex; veins dark brown; humeral cell and basal part of costal cell light brown; anal vein approximately 7 times as long as the width of bm cell; alula without a distinct posterodistal lobe, with marginal microtrichia; halter yellow, darkened basally. Legs: all coxae and trochanters normal and simple; fore femur (Figs 1,2) yellow, basally with 2 distinct anteroventral setae, 1 of which is very long (approximately 3 times as long as the other), and submedianly with a group of spinules and 1 small tubercle, and 3–4 ventral setae in the distal part; mid-femur dark brown and hind femur yellow, both without any distinct setae or spines; fore tibia with a row of 5–7 ventral short spinules in the basal third and ventrally with setulae in the distal third; middle tibia yellow with an anteroventral seta at the distal third and ventrally covered with distinct setulae in the distal half: hind tibia yellow and anterodorsally with a darkened mark like an osmeterium near the middle; all tarsi yellow, darkened apically; hind first tarsomere with a row of anteroventral setae that are approximately 1.3 times as long as the width of first tarsomere.

Abdomen: black and shiny; tergites sparsely clothed with setulae, without macrochaetae; third sternite longitudinally elongate with 4–5 pairs of setulae; 4th sternite rounded triangular-shaped and sparsely covered with 12–13 setulae; epandrium slender in lateral view, with a pair of strong dorsal setae and 3 pairs of posterior setae (Fig. 3); upper part of surstylus with slight projection (Fig. 4).

Body length: 3.0–3.8 mm (n = 20).

Female. Unknown.

Holotype. ♂, Sapa (1850 m a.s.l.), Lao Cai, Vietnam, 6.x.1999, M. Iwasa (OU).

Paratypes. 10♂, same data as holotype (IEBR); 25♂, same locality as holotype, 4–5.x.1999, M. Iwasa (OU); 9♂, Phang Si Pang (1970 m a.s.l.), Lai Chau Province, 4.x.1995, H. Kurahashi (OU).

Distribution. Vietnam.

Etymology. This species is named for the long anteroventral seta on the male fore femur.

Remarks. This species is easily distinguishable from previously described species of Dicranosepsis in having 1 short and 1 long anteroventral seta at the basal third of the male fore femur. The adults were collected from cow dung.

Male. Head: frons black and shining; face and facial orbit dark brown to black; gena and occiput black and thinly pruinose; antennal segments entirely black, third segment pubescent; arista black and bare; vibrissal angle with 3 moderately developed setae; genal margin with more than 10 peristomal setae in a row and 1 strong seta at genal angle; 1 oc, 1 vti, 1 vte, 1 pvt; or absent.

Thorax: wholly black; mesonotum and scutellum thinly pruinose; postpronotal lobe thinly pruinose in anterior half and posteriorly shining; proepisternum thinly pruinose; anepisternum glossy; katepisternum anteroventrally shining and posterodorsally pruinose; anepimeron anteriorly shining and posteriorly pruinose; meron thinly pruinose; katatergite and metanotum subshining, central part of metanotum glossy; 1 pprn, 2 npl, 2 dc, 1 sa, 1 pa, 1 m, 1 sc. Wings: hyaline, slightly tinged with brown, without dark spot near apex; veins dark brown; humeral cell and basal part of costal cell light brown; anal vein approximately 7 times as long as the width of bm cell; alula without a distinct posterodistal lobe, bearing microtrichia marginally; halter yellow, darkened basally. Legs: fore coxae slightly bent innerside; all trochanters normal and simple; fore femur (Figs 5,6) yellow, with 2 anteroventral setae in the basal third, 1 of which is 2 times as long as the other, and with small anteroventral and ventral tubercles preceded by a median group of spinules, and with 3 ventral setae distally; mid- and hind femora yellow and without any distinct setae or spinules; fore tibia (Fig. 5) with 3–4 ventral spinules in the basal third and ventrally covered with setulae in the distal third; middle tibia yellow, with an anteroventral seta at the distal third; hind tibia yellow, anterodorsally with a weak darkened mark like an osmeterium near the middle; all tarsi yellow, darkened apically; hind first tarsomere with a row of anteroventral setae that are approximately 2 times as long as the width of the first tarsomere.

Abdomen: black and shining; tergites sparsely with setulae, without macrochaetae; third sternite longitudinally elongate with 3 pairs of setulae; 4th sternite rounded triangular-shaped and sparsely covered with 9–10 setulae; epandrium comparatively thick in lateral view with a pair of strong dorsal setae and 3 pairs of posterior setae, and anteroventral part perpendicular (Fig. 7); upper part of surstylus with slight projection (Fig. 8).

Body length: 3.5–3.8 mm (n = 13).

Female. Unknown.

Holotype. ♂, Sapa (1850 m a.s.l.), Lao Cai, Vietnam, 6.x.1999, M. Iwasa (OU).

Paratypes. 6♂, same data as holotype (IEBR); 4♂, same locality as holotype, 4.x.1999, M. Iwasa (OU); 2♂, Mount Phang Si Pang (1970 m a.s.l.), Lai Chau, Vietnam, 4.x.1995, H. Kurahashi (OU).

Distribution. Vietnam.

Etymology. This species is named after Dr H. Kurahashi, who collected some of the type specimens.

Remarks. This species resembles D. longa sp. nov. in the structure of the male foreleg, but is distinguishable from it by having 3 anteroventral setae equidistant to each other in the basal half of the fore femur and by the shape of the epandrium in males (the ventral part of the epandrium is perpendicular to the anterior margin of the epandrium in lateral view). The adults were collected from cow dung.

Male. Head: frons black and shining; face and facial orbit dark brown to black; gena and occiput black and thinly pruinose; antennal segments entirely black, third segment pubescent; arista black and bare; vibrissal angle with 2–3 moderately developed setae; genal margin with a row of peristomal setae and 1 strong seta at genal angle; 1 oc, 1 vti, 1 vte, 1 pvt; or absent.

Thorax: wholly black; mesonotum and scutellum thinly pruinose; postpronotal lobe thinly pruinose, shining only around pprn seta: proepisternum thinly pruinose; anepisternum glossy; katepisternum anteroventrally shining and posterodorsally pruinose; anepimeron anteriorly shining or subshining and posteriorly pruinose; meron thinly pruinose; katatergite and metanotum subshining, central part of metanotum glossy; 1 pprn, 2 npl, 2 dc, 1 sa, 1 pa, 1 m, 1 sc. Wings: hyaline, slightly tinged with brown without dark spot near apex; veins dark brown; humeral cell and basal part of costal cell light brown; anal vein approximately 8 times as long as the width of bm cell; alula without a distinct posterodistal lobe, with microtrichia marginally; halter yellow, darkened basally. Legs: all coxae and trochanters normal and simple; fore femur (Figs 9,10) yellow, with a prominently strong ventral seta at the basal 4th and an anteroventral and a posteroventral tubercle followed by 1–2 short posteroventral setae at the near distal third, and with 3–4 setae distally; middle and hind femora yellow and without any distinct setae or spines; fore tibia (Fig. 9) with a row of ventral spinules in the basal third and ventrally clothed with setulae in the distal third; middle tibia yellow, with an anteroventral seta at the distal third and ventrally covered with distinct setulae in the distal half; hind tibia yellow, anterodorsally with a darkened mark like an osmeterium near the middle; all tarsi yellow, darkened apically; first hind tarsomere with a row of anteroventral setae as long as the width of first tarsomere.

Abdomen: black and shining; tergites sparsely clothed with setulae, without macrochaetae; third sternite longitudinally elongate with 5 pairs of setulae; 4th sternite rounded triangular-shaped and sparsely covered with 12–13 setulae; epandrium slender in lateral view with a pair of strong dorsal setae and 3 pairs of posterior setae (Fig. 11); upper part of surstylus with slight projection (Fig. 12).

Body length: 3.0–3.8 mm (n = 7).

Female. Unknown.

Holotype. ♂, Sapa (1850 m a.s.l.), Lao Cai, Vietnam, 6.x.1999, M. Iwasa (OU).

Paratypes. 5♂, same data as holotype (IEBR); 1♂, same locality as holotype, 4.x.1999, M. Iwasa (OU).

Distribution. Vietnam.

Etymology. This species is named for the strong ventral seta at the basal part of the male fore femur.

Remarks. This species is easily distinguishable from other species of Dicranosepsis by having a prominently strong ventral seta at the basal 4th of the male fore femur. The adults were collected from cow dung.

Male. Head: frons black and shining; face and facial orbit dark brown, facial carina brown; gena and occiput black and thinly pruinose; antennal segments entirely black, third segment pubescent; arista black and bare; vibrissal angle with 3 moderately developed setae; genal margin with a row of peristomal setae and 1 strong seta at genal angle; 1 oc, 1 vti, 1 vte, 1 pvt; or absent.

Thorax: wholly black; mesonotum and scutellum thinly pruinose; postpronotal lobe thinly pruinose, and shining only around pprn seta; proepisternum thinly pruinose; anepisternum glossy; katepisternum anteroventrally shining and posterodorsally pruinose; anepimeron anteriorly shining and posteriorly pruinose; meron thinly pruinose; katatergite and metanotum subshining, central part of metanotum glossy; 1 pprn, 2 npl, 2 dc, 1 sa, 1 pa, 1 m, 1 sc. Wings: hyaline, slightly tinged with brown, without dark spot near apex; veins dark brown; humeral cell and basal part of costal cell light brown; anal vein approximately 6.5 times as long as the width of bm cell; alula without a distinct posterodistal lobe, bearing microtrichia marginally; halter yellow, darkened basally. Legs: fore coxae (Fig. 13) yellow, sinuate and thick in basal half; fore trochanters (Fig. 14) elongate, with 2 distinct ventral spinules curled apically; fore femur (Figs 14,15) yellow, with an anteroventral and a posteroventral tubercle preceded by a median group of spinules and distally with 3 ventral setae; middle and hind femora yellow and without any distinct setae or spinules; fore tibia (Fig. 14) with 3–4 ventral spinules in the basal third and excavated at the middle; middle tibia yellow, with an anteroventral seta at the distal third; hind tibia yellow, anterodorsally with a darkened mark like an osmeterium; fore and middle first tarsomeres yellow, darkened apically; hind first tarsomere with a row of anteroventral setulae that are approximately 2 times as long as the width of first tarsomere; second to fifth tarsomeres entirely black.

Abdomen: black and shining; tergites sparsely with setulae, without macrochaetae; third sternite longitudinally elongate with 3–4 pairs of setulae; 4th sternite oval and sparsely covered with 9–10 setulae; epandrium comparatively thick in lateral view with a pair of strong dorsal setae and 4 pairs of posterior setae, and anteroventral part of epandrium gently curved (Fig. 16); upper part of surstylus with slight projection (Fig. 17).

Body length: 3.3–3.5 mm (n = 20).

Female. Unknown.

Holotype. ♂, Sapa (1850 m a.s.l.), Lao Cai, Vietnam, 5.x.1999, M. Iwasa (OU).

Paratypes. 15♂, same data as holotype (IEBR); 11♂, same locality as holotype, 4.x.1999, M. Iwasa (OU); 6♂, Mount Phang Si Pang (1970 m a.s.l.), Lai Chau, Vietnam, 4.x.1995, H. Kurahashi (OU); 2♂, Sapa (1500 m a.s.l.), Vietnam, 2.x.1995, H. Kurahashi (OU).

Distribution. Vietnam.

Etymology. This species is named for the sinuate fore coxae in males.

Remarks. This species is remarkable in Dicranosepsis for having sinuate coxae and elongate trochanters in the male forelegs. The adults were collected from cow dung.

Male. Head: frons black and shining; face black, facial carina brown; gena and occiput black and thinly pruinose; antennal segments entirely black, third segment pubescent; arista black and bare; vibrissal angle with 3 moderately developed setae; genal margin with a row of peristomal setae, and genal lower part with long and wavy hairs instead of a genal seta (Fig. 18), 1 oc, 1 vti, 1 vte, 1 pvt; or absent.

Thorax: wholly black; mesonotum and scutellum thinly pruinose; postpronotal lobe thinly pruinose, with posterior shining spot around pprn seta; proepisternum thinly pruinose; anepisternum glossy; katepisternum anteroventrally shining and posterodorsally pruinose; anepimeron anteriorly shining and posteriorly pruinose; meron thinly pruinose; katatergite and metanotum subshining, central part of metanotum widely glossy; 1 pprn, 2 npl, 2 dc, 1 sa, 1 pa, 1 m, 1 sc. Wings: hyaline, slightly tinged with brown; veins dark brown; humeral cell and basal part of costal cell light brown; anal vein approximately 5.5 times as long as the width of bm cell; alula without a distinct posterodistal lobe, bearing microtrichia marginally; halter yellow, darkened basally. Legs: all coxae and trochanters normal and simple; fore femur (Figs 19,20) yellow, with 2 anterobasal setae, and antero- and posteroventral tubercles preceded by a median group of spinules, and distally with 3–4 ventral setae; middle and hind femora yellow and without any distinct setae or spinules; fore tibia (Figs 19,20) with 3–4 ventral spinules in the basal third and ventrally covered with setulae in the distal third; middle tibia yellow, with an anteroventral seta at the distal third; hind tibia yellow, anterodorsally with a darkened mark like an osmeterium near the middle; all tarsi yellow, darkened apically; hind first tarsomere with a row of anteroventral setae that are as long as the width of first tarsomere.

Abdomen: black and shining; tergites sparsely with setulae, without macrochaetae; third sternite longitudinally elongate with 4–5 pairs of setulae; 4th sternite oval and sparsely covered with 9–10 setulae; epandrium comparatively thin in lateral view with a pair of strong dorsal setae and 2 pairs of posterior setae, and anteroventral part of epandrium gently curved (Fig. 21); upper part of surstylus with slight projection (Fig. 22).

Body length: 2.9–3.0 mm (n = 4).

Female. Unknown.

Holotype. ♂, Mount Phang Si Pang (1970 m a.s.l.), Lai Chau, Vietnam, 4.x.1995, H. Kurahashi (OU).

Paratypes. 2♂, same data as holotype (IEBR); 1♂, Sapa (1500 m a.s.l.), Vietnam, 2.x.1995, H. Kurahashi (OU).

Distribution. Vietnam.

Etymology. This species is named for the characteristic wavy hairs on the lower genal part of the head in males.

Remarks. This species resembles D. revocans (Walker, 1860) in the structure of the male forelegs, but is easily distinguishable by males having long and characteristic wavy hairs on the lower genal part of the head.

Male. Head: frons black and shining; face black, facial carina and facial orbit brown; gena and occiput black and thinly pruinose; antennal segments entirely black, third segment pubescent; arista black and bare; vibrissal angle with 3 moderately developed setae; genal margin with more than 10 peristomal setae and with a distinct seta at genal angle; 1 oc, 1 vti, 1 vte, 1 pvt; or absent.

Thorax: wholly black; mesonotum and scutellum thinly pruinose; postpronotal lobe thinly pruinose, with posterior shining spot around pprn seta; proepisternum thinly pruinose; anepisternum glossy; katepisternum anteroventrally shining and posterodorsally pruinose; anepimeron thinly pruinose, only central part shining; meron thinly pruinose; katatergite and metanotum subshining, central part of metanotum glossy; 1 pprn, 2 npl, 2 dc, 1 sa, 1 pa, 1 m, 1 sc. Wings: hyaline, slightly tinged with brown; veins dark brown; humeral cell and basal part of costal cell light brown; anal vein approximately 6.8 times as long as the width of bm cell; alula without a distinct posterodistal lobe, with microtrichia marginally; halter yellow, darkened basally. Legs: all coxae and trochanters normal and simple; fore femur (Figs 23,24) yellow, with a long anteroventral seta at the basal 4th, and with a group of median spinules accompanied by a small posteroventral tubercle next, and distally with 3 ventral setae; middle and hind femora yellow and without any distinct setae or spinules; fore tibia (Fig. 23) with 4–5 ventral spinules in the basal third and ventrally covered with setulae in the distal part; middle tibia yellow, with an anteroventral seta at the distal third and strong apical anteroventral and posteroventral spurs; hind tibia (Fig. 25) yellow, anterodorsally with distinct osmeterium accompanied by comparatively long dorsal setulae; all tarsi yellow, darkened apically; rows of anteroventral and posteroventral setae on mid-first tarsomere somewhat long and stout (Fig. 26); hind first tarsomere with a row of anteroventral setulae that are as long as the width of first tarsomere.

Abdomen: black and shining; tergites sparsely with setulae, without macrochaetae; third sternite longitudinally elongate with 4 pairs of short setulae; 4th sternite rounded triangular-shaped and sparsely covered with 13–14 short setulae; anteroventral part of epandrium angularly curved with a pair of strong dorsal setae and 3 pairs of posterior setae (Fig. 27); upper part of surstylus with slight projection (Fig. 28).

Body length: 3.0–3.3 mm (n = 8).

Female. Unknown.

Holotype. ♂, Sapa (1600 m a.s.l.), Lao Cai, Vietnam, 5.x.1999, M. Iwasa (OU).

Paratypes. 2♂, same data as holotype (IEBR); 1♂, same locality as holotype, 6.x.1999, M. Iwasa (IEBR); 1♂, same locality as holotype, 4.x.1999, M. Iwasa (OU); 3♂, Sapa (800–1200 m a.s.l.), Lao Cai, Vietnam, 6–7.x.1995, Kurahashi (OU).

Distribution. Vietnam.

Etymology. This species is named after the country in which the type specimens were collected.

Remarks. This species is very similar to D. unipilosaDuda, 1926 in the features of the male forelegs, but differs from it in having a long anteroventral seta at the basal third of the fore femur and rows of stout anteroventral and posteroventral setae on the first tarsomere of the midlegs, and a distinct osmeterium on the hind tibia in males.