Centorisoma scutatum, 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 : 24-25

Centorisoma scutatum sp. n.

Figs 4, 9 , 14 , 31–34

Diagnosis. Gena broad, about 0.5 times as wide as postpedicel. Postpedicel about 1.8 times as long as its basal breadth. Legs yellow except fore tibia and tarsus brown. Cercus large, scutelliform, distal portion round. Postgonite without minute serrations on inner margin and slightly produced beyond basiphallus.

Description. Male. Body length 3.6 mm, wing length 2.5 mm.

Head brown without microtomentum, about 0.8 times as long as high, 1.1 times as wide as thorax; face yellow except ventral 1/2 with a triangular brown spot, somewhat concave in lateral view, facial carina indistinct; epistoma yellow; frons brownish yellow except anterior 1/4 yellow, about 0.9 times as long as wide, projecting only slightly in front of eye; gena broad, about 0.5 times as wide as postpedicel, anteriorly yellow with lower margin brown; parafacial narrowed. Ocellar triangle blackish brown, smooth, shiny, reaching to anterior margin of frons, with pointed apex; ocellar tubercle light brown. Cephalic setae and setulae black; oc and pvt hair-like, oc as long as pvt; vte and vti developed, vte slightly longer than vti. Antenna ( Figs. 14 ) yellowish brown with thick grayish microtomentum, but basal portion of pedicel brown, distal 1/2 of postpedicel black; postpedicel about 1.8 times as long as its basal breadth, basal 1/2 weakly concave; arista white except basal segment yellow, with short pale yellow setulae. Proboscis yellow with yellow setulae; palpus brown with brown 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 for anteroventral portion of anepisternum, anterior portion of anepimeron, ventral 2/3 of katepisternum and ventral 1/2 of katepimeron black. Scutellum about 0.7 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 subequal to p npl; a pa developed, p pa hairlike, a pa about 1.2 times as long as p pa; 1 dc, hair-like, 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 longer than diameter of tibia. Tibial organ oblong, narrow. Wing ( Fig. 9 ) about 2.6 times as long as wide, hyaline; veins brown. Relative lengths of 2nd: 3rd: 4th costal sections = 5: 3: 2; crossveins r-m and m-m not approximate, r-m at basal 0.5 of discal cell. Halter pale yellow.

Abdomen shiny blackish brown except for basal portion of tergite 1 yellow; venter yellow. Setulae on abdomen brown.

Male genitalia ( Figs. 31–34 ): Epandrium brown with many setulae; surstylus horizontally articulated with epandrium, strongly narrowed at apex, slightly short. Cercus rather large, scutelliform, distal portion round, articulated with distinct inner surstylar plate. Gonites arranged in a row, with a distinct demarcation at middle; postgonite without minute serrations on inner margin, gradually narrowed distally, slightly produced beyond basiphallus; basiphallus short; phallapodeme long, extended near base of basiphallus, with basal stalk broad in lateral view. Hypandrium broad.

Female. Unknown.

Type material. Holotype 3, CHINA: Ningxia: Liupanshan Mountain, 7. VII. 2008, Jingxian Liu. Paratype 1 3, Beijing: Shidu, 1–2. VII. 2009, Jinjing Wang. All type specimens were stored in 75% ethanol.

Distribution. China: Ningxia, Beijing.

Remarks. The new species is somewhat similar to C. kyushuense Kanmiya in the following aspects: postpedicel elongate, about 1.8 times as long as its basal breadth; legs yellow except fore tibia and tarsus brown; gonites distinctly divided into two parts, postgonite without minute serrations on inner margin near basiphallus. But it can be separated from the latter by the following features: gena yellow except with posterior 1/2 black; cercus rather large, scutelliform, distal portion round; surstylus slightly short. In C. kyushuense , the gena is entirely shiny black; the cercus is rather broad, its distal portion with a big convexity; the surstylus is very long ( Kanmiya 1983).

Etymology. The specific name is from the Latin scutatus (“scutatus”), refers to the shape of cercus.

Figures

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 31 – 34. Centorisoma scutatum sp. n., male. 31 epandrium, posterior view; 32 epandrium, lateral view; 33 hypandrium and phallic complex, ventral view; 34 hypandrium and phallic complex, lateral view. Scale bar = 0.1 mm.