Centorisoma convexum, Liu, Xiaoyan & Yang, Ding, 2014

Liu, Xiaoyan & Yang, Ding, 2014, Five new species of Centorisoma Becker from China, with an updated key to world species (Diptera, Chloropidae), Zootaxa 3821 (1), pp. 101-115 : 103-105

Centorisoma convexum sp. n.

Figs 1, 6–12

Diagnosis. Postpedicel 1.5 times as long as its basal breadth. Legs yellow except distal 1/2 of fore tibia and fore tarsus brown. Cercus nearly quadrate with apical margin round. Postgonite without minute serrations on inner margin, distinctly produced beyond basiphallus.

Description. Male. Body length 3.4 mm, wing length 2.3 mm.

Head brown without microtomentum, 0.8 times as long as high, 1.1 times as wide as thorax; face yellow with a triangular brown spot more or less on ventral 1/2, somewhat concave in lateral view, facial carina indistinct; frons yellow, 0.9 times as long as wide, projecting only slightly in front of eye; gena broad, 0.5 times as wide as postpedicel, anteriorly yellow with lower margin brown; parafacial indistinct. Ocellar triangle brown, smooth, shiny, reaching to anterior 0.9 of frons, with pointed apex; ocellar tubercle light brown. Cephalic setae and setulae black; oc and poc hair-like, oc as long as poc; vte and vti developed, vte slightly longer than vti. Antenna yellow with thick grayish microtomentum except distal 1/4 of postpedicel black; postpedicel 1.5 times as long as its basal breadth, basal 1/3 weakly concave on dorsal margin; arista white except basal segment yellow, with short pale yellow setulae. Proboscis yellow with yellow setulae; palpus brown with brown setulae.

Thorax brown with microtomentum, evenly covered with short setulae. Scutum with granulated microsculpture, 1.2 times as long as wide. Thoracic pleuron shiny brown without microtomentum except for anteroventral portion of anepisternum, ventral 2/3 of katepisternum and ventral 1/2 of katepimeron black.

Scutellum 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 developed and p pa hair-like, a pa 1.2 times as long as p pa; 1 dc hair-like, as long as a pa. Legs yellow except for fore tarsus and apical half of fore tibia, both of which are brown. Setulae on legs brown. Mid tibia with a distinct black subapical spur. Tibial organ oblong, narrow. Wing 2.7 times as long as wide, hyaline; veins brown. Relative lengths of 2nd: 3rd: 4th costal sections = 2.2: 2: 1; crossveins r-m and m-m not approximate, r-m at basal 0.6 of discal cell. Halter pale yellow.

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

Male genitalia ( Figs. 6–9 ): Epandrium brown with many setulae; surstylus horizontally articulated with epandrium, strongly narrowed at apex. Cercus well developed and nearly quadrate with apical margin round, articulated with distinct inner surstylar plate. Gonites arranged in a row, with a distinct demarcation at middle; postgonite gradually narrowed distally without minute serrations on inner margin, distinctly produced beyond basiphallus; basiphallus short; phallapodeme long, extended to base of basiphallus, with basal stalk broad in lateral view. Hypandrium broad.

Female. Body length 2.7 mm, wing length 2.4 mm.

Female genitalia ( Figs. 10–12 ): Tergite 9 nearly triangular, slightly wider than long, with 3 long setae; sternite 9 long, apically round with long stout setae. Cercus short and stout with some long setae.

Type material. Holotype ♂, CHINA: Guizhou: Suiyang, Kuankuoshui, 9. VI. 2010, Jie Zeng. Paratypes 2 ♂, 2 ♀, Beijing: Mentougou, Xiaolongmen, 13. VIII. 2009, Hui Yu; 1 ♀, Hebei: Xiaowutai, Shanjiankougou, 24. VI. 2009, Junchao Wang.

Distribution. China: Guizhou, Beijing, Hebei.

Remarks. The new species is somewhat similar to C. scutatum Liu & Yang in having the gena yellow except posterior 1/2 black, the legs yellow except for apical half of fore tibia and fore tarsus brown and the postgonite without minute serrations on inner margin near basiphallus. It can be separated from the latter by the following features: postpedicel yellow except distal 1/4 black, 1.5 times as long as its basal breadth; cercus nearly quadrate. In C. scutatum , the postpedicel is yellowish brown except distal 1/2 black, 1.8 times as long as its basal breadth; the cercus is scutelliform ( Liu & Yang 2012).

Etymology. The specific name is from the Latin convexus (“convex”), refers to the apical margin of the cercus being round.

Figures

FIGURES 6 – 9. Centorisoma convexum sp. n., male. 6 epandrium, posterior view; 7 epandrium, lateral view; 8 hypandrium and phallic complex, ventral view; 9 hypandrium and phallic complex, lateral view. Scale bar = 0.1 mm.

FIGURES 10 – 12. Centorisoma convexum sp. n. female. 10 abdominal terminalia, dorsal view; 11 abdominal terminalia, lateral view; 12 abdominal terminalia, ventral view. Scale bar = 0.1 mm.