Centorisoma divisum, Liu, Xiaoyan & Yang, Ding, 2012

Liu, Xiaoyan & Yang, Ding, 2012, The genus Centorisoma Becker in China, with a key to world species (Diptera, Chloropidae), Zootaxa 3361, pp. 18-32 : 20-22

Centorisoma divisum sp. n.

Figs 1 , 6 , 11 , 16–22

Diagnosis. Postpedicel about 1.7 times as long as its basal breadth. Legs yellow except fore tibia and tarsus brown. Wing tinged yellowish brown on mid-anterior area. Cercus divided into two parts, oblong. Postgonite bearing minute serrations on inner margin and not produced beyond basiphallus.

Description. Male. Body length 3.2 mm, wing length 2.3 mm.

Head brown without microtomentum, about as long as high, 1.1 times as wide as thorax; face yellow, somewhat concave in lateral view, facial carina indistinct; epistoma yellow; frons yellow, about 0.9 times as long as wide, projecting only slightly in front of eye; gena anteriorly yellow with lower margin brown, broad, about 0.8 times as wide as postpedicel; parafacial distinct, yellow. Ocellar triangle brown, smooth, shiny, reaching to anterior margin of frons, with pointed apex; ocellar tubercle light brown. Occiput dark brown. Cephalic setae and setulae black; oc and pvt hair-like, oc as long as pvt; vte and vti developed, vte as long as vti. Antenna ( Figs. 11 ) yellowish brown with thick grayish microtomentum, but distal portion of postpedicel dark brown; postpedicel about 1.7 times as long as its basal breadth, basal 1/2 weakly concave; arista white except basal segment yellow, with short pale yellow setulae. Proboscis yellowish brown to yellow with yellow setulae; palpus brown with brown setulae.

Thorax black with microtomentum, evenly covered with short setulae. Scutum with granulated microsculpture, about 1.2 times as long as wide. Thoracic pleuron shiny brown without microtomentum except for anteroventral portion of anepisternum, anterior portion of anepimeron, ventral 2/3 of katepisternum and ventral 1/2 of katepimeron black. Scutellum about 0.6 times as long as wide; ap sc short, distinctly shorter than scutellum. Setae and setulae on thorax black; npl 1+2, a npl hair-like, p npl developed, a npl as long as p npl; a pa and p pa developed, a pa about 2 times as long as p pa; 1 dc developed, as long as a pa. Legs yellow except fore tibia and tarsus brown, basal portion of fore tibia yellow. Setulae on legs brown. Mid tibia with a distinct black subapical spur nearly as long as diameter of tibia. Tibial organ oblong, narrow. Wing ( Fig. 6 ) about 2.9 times as long as wide, hyaline, tinged yellowish brown on mid-anterior area; veins brown. Relative lengths of 2nd: 3rd: 4th costal sections = 5: 4: 3; crossveins r-m and m-m not approximate, r-m at basal 0.65 of discal cell. Halter pale yellow on knob, slightly brown on stem.

Abdomen shiny dark brown; venter yellow. Setulae on abdomen brown.

Male genitalia ( Figs. 16–19 ): Epandrium brown with many setulae; surstylus horizontally articulated with epandrium, strongly narrowed at apex. Cercus divided into two parts, oblong, distally pointed with some long setulae, articulated with distinct inner surstylar plate. Gonites arranged in a row, with a distinct demarcation at basal 3/5 of its length; postgonite gradually narrowed distally, not produced beyond basiphallus and bearing minute serrations on inner margin near basiphallus; basiphallus short; phallapodeme long, extended to base of basiphallus with basal stalk broad in lateral view. Hypandrium broad.

Female. Body length 3.6 mm, wing length 2.4 mm.

Female genitalia ( Figs. 20–22 ): Tergite 9 rhombic, about as long as wide, with 3 long setae; sternite 9 long, apically round with long stout setae at apical portion. Cercus short and stout with some long setae.

Type material. Holotype 3, CHINA: Inner Mongolia: Helanshan Mountain, Shuimogou, Nangou, 6. VIII. 2010, Yan Li. Paratypes 1 3, Helanshan Mountain, Shuimogou, Hougou, 4. VIII. 2010, Lihua Wang; 1 3, Helanshan Mountain, Gulamu, Luanchaigou, 10. VIII. 2010, Yan Li; 1 Ƥ, Helanshan Mountain, Halawu, Beigou, 28. VII. 2010, Lihua Wang. All type specimens were stored in 75% ethanol.

Distribution. China: Inner Mongolia.

Remarks. The new species is somewhat similar to C. nigraristatum Yang & Yang in having the wing tinged yellowish brown on the mid-anterior area, the gena about 0.8 times as wide as the postpedicel, and the postgonite not produced beyond the basiphallus. But it can be separated from the latter by the following features: arista white except basal segment yellow; legs yellow except fore tibia and tarsus brown; cercus divided into two parts, oblong. In C. nigraristatum , the arista is blackish brown; the legs are brownish black to black except for the coxae and trochanters brownish yellow to yellow, the apex of the femora, basal portion of the fore tibia, and the basal and apical portions of the mid and hind tibiae brownish yellow to yellow, fore tarsus wholly black; the cercus is nearly quadrate with a small concavity on the apical margin ( Yang & Yang 1992).

Etymology. The specific name is from the Latin divisus (“divided”), refers to the cercus divided into two parts.

Centorisoma gansuensis sp. n. Figs 2 , 7 , 12 , 23–26

Diagnosis. Gena broad, about as wide as postpedicel. Postpedicel about 1.8 times as long as its basal breadth. Arista brown except basal segment dark brown. Wing tinged yellowish brown on mid-anterior area. Cercus well developed, apical margin with a large concavity. Postgonite bearing minute serrations on inner margin and not produced beyond basiphallus.

Description. Male. Body length 3.7 mm, wing length 2.7 mm.

Head black without microtomentum, about 0.9 times as long as high, 1.2 times as wide as thorax; face yellow, somewhat concave in lateral view, facial carina indistinct; epistoma yellow; frons yellow, about 0.8 times as long as wide, projecting only slightly in front of eye; gena anteriorly yellow, broad, about as wide as postpedicel, with some yellow setulae; parafacial yellow, narrow. Ocellar triangle black, smooth, shiny, reaching to anterior margin of frons, with pointed apex; ocellar tubercle light black. Cephalic setae and setulae black; oc and pvt hair-like, oc as long as pvt; vte and vti developed, vte as long as vti. Antenna ( Figs. 12 ) black with thick grayish microtomentum, but distal portion of pedicel yellowish brown, basoventral portion of postpedicel yellow; postpedicel about 1.8 times as long as its basal breadth, basal 1/2 weakly concave; arista brown except basal segment dark brown, with short brown setulae. Proboscis yellowish brown to yellow with yellow setulae; palpus black with black setulae.

Thorax black with microtomentum, evenly covered with short setulae. Scutum with granulated microsculpture, about 1.1 times as long as wide. Thoracic pleuron shiny brown without microtomentum except anteroventral portion of anepisternum, anterior portion of anepimeron, ventral 2/3 of katepisternum and ventral portion of katepimeron black. Scutellum about 0.6 times as long as wide; ap sc short, distinctly longer than scutellum. Setae and setulae on thorax black; npl 1+2, a npl hair-like, p npl developed, a npl subequal to p npl; a pa and p pa developed, a pa about 2 times as long as p pa; 1 dc developed, as long as a pa. Legs yellow except femora brown, distally yellow; fore tibia yellowish brown except basal 1/2 yellow; hind tibia yellow except middle 1/4 brown; fore tarsus, mid and hind tarsomeres 3-5 brown. Setulae on legs brown. Mid tibia with a distinct black subapical spur nearly as long as diameter of tibia. Tibial organ oblong, narrow. Wing ( Fig. 7 ) about 2.9 times as long as wide, hyaline, tinged yellowish brown on mid-anterior area; veins brown. Relative lengths of 2nd: 3rd: 4th costal sections = 4: 3: 2.4; crossveins r-m and m-m not approximate, r-m at basal 0.6 of discal cell. Halter pale yellow on knob, brown on stem.

Abdomen shiny brown; venter yellow. Setulae on abdomen brown.

Male genitalia ( Figs. 23–26 ): Epandrium brown with many setulae; surstylus horizontally articulated with epandrium, strongly narrowed at apex. Cercus well developed with a large concavity on apical margin, articulated with distinct inner surstylar plate. Gonites arranged in a row, with a distinct demarcation at middle; postgonite gradually narrowed distally, not produced beyond basiphallus and bearing minute serrations on inner margin near basiphallus; basiphallus short; phallapodeme long, extended to base of basiphallus, with basal stalk broad in lateral view. Hypandrium broad.

Female. Unknown.

Type material. Holotype 3, CHINA: Gansu: Nankonggangmu, 8. VII. 2010, Xiao Zhang. Type specimen was stored in 75% ethanol.

Distribution. China: Gansu.

Remarks. The new species is somewhat similar to C. nigraristatum Yang & Yang in having the wing tinged brown on mid-anterior area and the arista blackish brown. But it can be separated from the latter by the following features: proboscis yellowish brown to yellow; mid tibia entirely yellow, middle 1/4 of hind tibia brown; cercus slightly longer than wide, with a large concavity on apical margin. In C. nigraristatum , the proboscis is light brown to black; the mid and hind tibiae are brown except for the basal and distal protions brownish yellow to yellow; the cercus is nearly quadrate, about 1.6 times as long as wide, and with a small concavity on the apical margin ( Yang & Yang 1992).

Etymology. The species is named after the type locality Gansu.

Figures

FIGURES 1. Centorisoma divisum sp. n., male. body, lateral view. Scale bar = 0.5 mm.

FIGURES 2. Centorisoma gansuensis sp. n., male. body, lateral view. Scale bar = 0.5 mm.

FIGURES 6 – 10. wing. 6 Centorisoma divisum sp. n.; 7 Centorisoma gansuensis sp. n.; 8 Centorisoma helanshanensis sp. n.; 9 Centorisoma scutatum sp. n.; 10 Centorisoma shaanxiensis sp. n. Scale bar = 0.25 mm.

FIGURES 11 – 15. antenna. 11 Centorisoma divisum sp. n.; 12 Centorisoma gansuensis sp. n.; 13 Centorisoma helanshanensis sp. n.; 14 Centorisoma scutatum sp. n.; 15 Centorisoma shaanxiensis sp. n. Scale bar = 0.1 mm.

FIGURES 16 – 19. Centorisoma divisum sp. n., male. 16 epandrium, posterior view; 17 epandrium, lateral view; 18 hypandrium and phallic complex, ventral view; 19 hypandrium and phallic complex, lateral view. Scale bar = 0.1 mm.

FIGURES 20 – 22. Centorisoma divisum sp. n. Female. 20 abdominal terminalia, dorsal view; 21 abdominal terminalia, lateral view; 22 abdominal terminalia, ventral view. Scale bar = 0.1 mm.

FIGURES 23 – 26. Centorisoma gansuensis sp. n., male. 23 epandrium, posterior view; 24 epandrium, lateral view; 25 hypandrium and phallic complex, ventral view; 26 hypandrium and phallic complex, lateral view. Scale bar = 0.1 mm.