Rhodesiella arcuata, Cai & Yang & Nartshuk & Liu, 2021

Cai, Xiaodong, Yang, Ding, Nartshuk, Emilia P. & Liu, Xiaoyan, 2021, Four new species of the genus Rhodesiella from Xizang Autonomous Region, China (Diptera: Chloropidae), Zootaxa 4970 (2), pp. 372-384 : 373-377

Rhodesiella arcuata sp. nov.

Figs 1 , 5 , 9–12

Diagnosis. Gena 0.25 times as deep as depth of first flagellomere. Antenna entirely yellow. Scutellum 1.3 times as long as wide, with 3 pairs of yellow scutellar setae on tubercles which are black on basal 1/2 and yellow on distal 1/2, 2 times as long as wide. Surstylus brown, well developed, long, rounded marginally, bent ventrad at basal 1/ 4 in dorsal view, cambered in lateral view.

Description. Male ( Figs. 1 , 5 ). Body length without antennae 2.74–3.00mm, wing length 2.72–2.80mm.

Head brownish black, much wider than long, length, width and height ratio as 1: 2: 1.3; frons yellowish brown, 0.86 times as long as wide, width measured at level of anterior ocellus, projecting only slightly in front of eye; face concave, yellow; gena narrow, 0.25 times as deep as depth of first flagellomere; parafacial inconspicuous. Ocellar triangle polished brownish black, smooth, reaching the anterior margin of frons with obtuse apex; ocellar tubercle yellowish brown. Occiput brownish black. Clypeus brownish black. Cephalic setulae and setae yellow. Antenna yellow, first flagellomere 0.65 times as long as deep; arista brownish black with short pubescence. Proboscis yellow with yellow setulae; palpus yellowish brown with yellow setulae.

Thorax black, slightly narrower than head. Scutum convex, as long as wide. Scutellum black, elongate, subtriangular, 1.3 times as long as wide and 0.68 times as long as scutum, with 3 pairs of yellow scutellar setae on tubercles which are black on basal 1/2 and yellow on distal 1/2, 2 times as long as wide. Ap sctl s 0.85 times as long as scutellum and 2.6 times as long as basal l sctl s; distal l sctl s 2 times as long as basal l sctl s. Distance between tips of the tubercles of basal and distal l sctl s slightly shorter than that between those of ap sctl s and distal l sctl s; distance between tips of tubercles of ap sctl s equal to that between those of ap sctl s and distal l sctl s. Thoracic setulae and setae yellow; npl s 1+1. Legs light yellow, only tarsomeres 5 brown. Setulae on legs mostly light yellow. Hind femur not thickened, 1.7 times as broad as succeeding tibia at middle. Mid-tibia with a distinct, yellow apical spur. Wing hyaline, 2.5 times as long as wide; veins brown, relative lengths of costal sections: 2nd: 3rd: 4th = 2.8: 2: 1; crossvein r-m distad beyond middle of discal cell, at basal 0.62 of its length; R 4+5 and M 1+2 nearly parallel medially; M 1+2 almost straight basally. Halter pale yellow.

Abdomen brown except for tergites 1+2 light yellow, tergite 2 brown laterally; venter yellow, except sternite 5 brown. Setulae black.

Male genitalia ( Figs. 9–12 ): Epandrium brown with yellow setulae, wider than long in dorsal view. Surstylus brown, well developed, long, rounded marginally, bent ventrad at basal 1/ 4 in dorsal view, basally broad and distally narrowed, cambered in lateral view. Hypandrium well developed, widened laterally, broadened and turned outwards on lateroventral part, concave medially, bucket-shaped in dorsal view. Pregonite basally broad, slightly incurved, with a triangular process on middle inner margin, distally narrowed. Postgonite highly incurved at middle and bearing 2 setae basally. Distiphallus relatively wide in the middle, distally narrowed.

Female. Unknown.

Type material. Holotype ♂, CHINA: Xizang: Linzhi, Hanmi , 29°22’N, 95°8’E, 5. viii. 2011, leg. Lihua Wang ; Paratype 1 ♂, Xizang: Linzhi , 29°38’N, 94°22’E, 19. viii. 2011, leg. Lihua Wang.

Etymology. The specific name is from the Latin arcuatus (“arcuate”), referring to the shape of the surstylus.

Remarks. The new species is similar to R. monticola KaNmIYa, 1987 from Taiwan in the following features: 3 pairs of yellow scutellar setae standing on tubercles which are black on basal 1/2 and yellow on distal 1/2, 2 times as long as wide; legs mostly yellow except tarsomeres 5 brown; hind femur not thickened; distance between tips of tubercles of basal and distal l sctl s slightly shorter than that between those of ap sctl s and distal l sctl s and distance between tips of tubercles of 2 ap sctl s equal to that between those of ap sctl s and distal l sctl s. But it can be separated from R. monticola by the following features: M 1+2 almost straight basally; surstylus brown, well developed, long, rounded marginally, bent toward venter of epandrium, cambered in lateral view. In R. monticola , M 1+2 is slightly curved basally; and the surstylus is dark brown, very large, 2 times as long as epandrium, oblong in lateral view ( Kanmiya, 1987).

Figures

FIGURES 1–4. Rhodesiella species, male habitus, lateral view. 1 R. arcuata sp. nov.; 2 R. longiseta sp. nov.; 3 R. perpendicularis sp. nov.; 4 R. uncata sp. nov. Scale bar = 0.5 mm.

FIGURES 5–8. Rhodesiella species, male habitus, dorsal view. 5 R. arcuata sp. nov.; 6 R. longiseta sp. nov.; 7 R. perpendicularis sp. nov.; 8 R. uncata sp. nov. Scale bar = 0.5 mm.

FIGURES 9–12. Rhodesiella arcuata sp. nov. male. 9 epandrium, posterior view; 10 epandrium, lateral view; 11 hypandrium and phallic complex, ventral view; 12 Scutellum, dorsal view. Scale bar = 0.1 mm.