Hexatoma (Eriocera) xizangensis, Zhang & Yang & Li & Yang, 2021

Zhang, Bing, Yang, Qicheng, Li, Yan & Yang, Ding, 2021, Hexatoma (Eriocera) Macquart (Diptera, Limoniidae) from Xizang, China, ZooKeys 1071, pp. 155-173 : 155

Hexatoma (Eriocera) xizangensis sp. nov.

Type material

. Holotype: male (CAU), China: Xizang, Beibeng, Jiangxincun, 2019.V.30, Qicheng Yang (light trap).

Diagnosis

. Femora are yellow. Wing is brownish yellow with the following markings: an oblique transverse hyaline marking from R extended up to CuA in base of wing; origin of Rs with a small hyaline marking; a longer oblique transverse hyaline marking from R extended to wing margin before cord; both sides of R2 with a hyaline marking; tip of R1 from Sc to R3 with an oblique transverse hyaline marking. R2 is moderately oblique, approximately as long as R3+4, placed before fork of R3+4; cell M1 is lacking; m-cu is near 2/3 of cell dm. Abdomen is brown to darker brown except segments 8-9 yellow. Posterior margin of ninth tergite has two small triangular processes; interbase is cylindrical, but stubby at base.

Description

. Male (N = 1): Body length 8.8 mm, wing length 7.2 mm.

Head (Figs 46) brown with long brown setae. Rostrum very short, brownish yellow; palpi brown. Antennal scape brown with brown setae; pedicel brownish yellow; flagellum is broken.

Thorax (Figs 46, 47) brown with long brown setae. Legs: coxae and trochanters brown with long brown setae; femora and tibiae yellow with brown setae; basal two segments of tarsi yellow with brown setae, reminder segments brownish yellow to brown with brown setae. Wing (Figs 46, 48) brownish yellow, anal cells more yellow; anal cells with hyaline markings at base; an oblique transverse hyaline marking from R extended up to CuA in base of wing; origin of Rs with a small hyaline marking; a longer oblique transverse hyaline marking from R extended to wing margin before cord; both sides of R2 with a hyaline marking; tip of R1 from Sc to R3 with an oblique transverse hyaline marking; veins slightly brown, very inconspicuous against ground. Venation: R2 oblique, approximately as long as R3+4, placed before fork of R3 + 4; cell M1 lacking; m-cu near 2/3 of cell dm. Halter (Figs 46, 47) length approximately 1.2 mm, pale brown.

Abdomen (Fig. 46) with brown setae. Segments 1-5 brown, segments 6-7 dark brown, segment 8 yellow.

Male terminalia (Figs 46, 50-54) yellow with brownish yellow setae. Posterior margin of ninth tergite with two small triangular processes, with abundant brown setae; gonocoxite moderately stubby; clasper of gonostylus slender, terminal spine decurved; lobe of gonostylus short and stout, middle margin swollen with setae; interbase cylindrical, stubby at base; aedeagus longer, apically directed ventrally.

Female

. Unknown.

Distribution

. China (Xizang).

Etymology

. The species is named after Xizang Autonomous Region, where the type locality is located.

Remarks

. This new species is very similar to H. (E.) decorata (Brunetti, 1918) from India (W Bengal) in having similar wing markings, but can be separated from it by the wing with a longer oblique transverse hyaline marking from R extended to wing margin before cord (Figs 46, 48) and the posterior margin of the ninth tergite with two small triangular processes (Fig. 50). In H. (E.) decorata , the oblique transverse hyaline marking from R extends to the CuP before the cord (Fig. 49 i.e., Brunetti, 1918: plate VII. fig. 12; Edwards, 1924: 304; Joseph, 1977: 427, fig. 16) and the posterior margin of the ninth tergite is produced, its margin concave (Fig. 55 i.e., Joseph, 1977: 427, fig. 7). These two species are very special within the subgenus Eriocera , be CAUse of their unique position and slope of vein R2 (Fig. 46, 48-49): it contacts vein R3+4 (and not vein R3 as is common in all Eriocera with a short vein R2+3+4), and is sloping forwards (also a very uncommon feature in Eriocera ).