Nephrotoma Meigen (Diptera, Tipulidae) from Xizang Autonomous Region, China

Abstract Eight species of the genus Nephrotoma were previously known to occur in Xizang Autonomous Region. Here, three species are added to the fauna of Xizang. Among them two species, N. beibengensissp. nov. and N. hanaesp. nov. are described and illustrated as new to science, and one species, N. evittata Alexander, 1935 is recorded from Xizang for the first time. The following four species are redescribed: N. claviformis Yang & Yang, 1987, N. didyma Yang & Yang, 1987, N. nigrohalterata Edwards, 1928, and N. xizangensis Yang & Yang, 1987. A key to the species of Nephrotoma from Xizang is presented.


Introduction
The genus Nephrotoma Meigen is one of the largest genera in the family Tipulidae. It is distributed worldwide with 163 known taxa from the Palaearctic Region and 127 taxa from the Oriental Region. Until now, 96 taxa are known in China (Oosterbroek 2020). In recent years, Men et al. (2015Men et al. ( , 2016Men et al. ( , 2017 and Ren and Yang (2017) increased our knowledge of the genus Nephrotoma in China. This genus is characterized by the following features: body usually yellow with dark stripes at top of prescutum or nearly entirely black; Rs short, cell m 1 sessile or shortly petiolate; male tergite 9 separated from sternite 9; posterior margin of tergite 9 varied in shape, usually with small black spines; outer gonostylus usually flattened and fleshy, and more or less acuminate; female cercus longer than hypovalva, blunt at tip, and hypovalva tapered or parallel-sided (Oosterbroek 1978;Tangelder 1983).
Xizang Autonomous Region (hereafter referred to as Xizang) is located in southwestern China and on the Qinghai-Tibet Plateau. This area is in the Palaearctic Region and on the border of the Oriental Region. With the formation and uplift of the Qinghai-Tibet Plateau, it has an average altitude of more than 4,500 m and a wide elevation range (Su et al. 2019). The formation of the Himalayas and the Qinghai-Tibet Plateau created a variety of climates and vicariance (Li and Fang 1999). Therefore, Xizang, is one of the most important biodiversity hotspots in the world. So far, only the following eight species of Nephrotoma are known to occur in this area: N. claviformis Yang & Yang, 1987, N. didyma Yang & Yang, 1987, N. distans Edwards, 1928, N. inorata Alexander, 1951, N. kaulbacki Alexander, 1951, N. libra Alexander, 1951, N. nigrohalterata Edwards, 1928, and N. xizangensis Yang & Yang, 1987 In the present paper, three species, including two new species, are added to the fauna of Xizang, and four species are redescribed. A key to the species of Nephrotoma from Xizang is presented.

Materials and methods
The specimens were studied and illustrated with a ZEISS Stemi 2000-c stereo microscope. Details of coloration were checked in specimens immersed in 75% ethyl alcohol (C2H5OH), except the dried specimens of N. claviformis Yang & Yang, 1987. Genitalic preparations of males were made using lactic acid solution (C3H6O3 > 85%) heated in a water-bath to 95 °C for 4-6 minutes. After examination, it was transferred to fresh glycerin (C3H8O3) and stored in a microvial pinned below the specimen. Type specimens are deposited in the Entomological Museum of China Agricultural University (CAU), Beijing.

Taxonomy
Key to species (males) of Nephrotoma from Xizang (Tibet), China

1
Vertex with triangular spots near inner margin of eye; prescutum with narrow black margin (Edwards 1928: 700 Mediotergite with a pair of black spots; tergite 9 with black caudal margin, lateral angle produced into a decurved spine (Yang and Yang 1987: 128 Posterior margin of mediotergite slightly dark; tergite 9 with a pair of large aduncous protuberances on posterior margin (Yang and Yang 1987: 128 Description. Male (n = 2): body length 10.4-10.5 mm, wing length 10.0 mm, antenna length 2.5 mm.
Head (Figs 1, 2). Mainly yellow. Frontal tubercle raised into discoid. Occipital marking dark brown, square, extended anteriorly to inner margin of eye. Rostrum yellow and nasus brown. Hairs on head black. Antenna brownish yellow, base of each segment darker; first flagellomere 1.3 times longer than second one. Proboscis brownish yellow, with black hairs. Palpus brown, with black hairs.
Thorax (Figs 1, 2). Mainly yellow. Pronotum yellow, lateral side dark brown, with yellow hairs. Prescutum with three black, longitudinal stripes; anterior end of lateral prescutal stripe bent outward, outer part brown and dull; prescutum with posterolateral dark-brown margin. Scutum with two black spots. Scutellum dark brown, with two triangular, yellow spots anteriorly. Mediotergite with an I-shaped, dark-brown marking. Anepisternum and katepisternum yellow. Anepimeron yellow with brown spot at antero-dorsal corner. Parascutellum pale brown. Anatergite brown; katatergite yellow. Meron yellow. Hairs on thorax dark yellow. Legs long, approximately three times as long as body, yellow except apices of tibiae and tarsi dark brown; hairs brown. Wing subhyaline, tinged with light brown; pterostigma pale with macrotrichiae; cell m 1 shortly petiolate, virtually invisible; apices of R 5 not curve up (Fig. 3). Halter with stem brownish yellow; knob pale yellow.
Remarks. This new species is similar to N. globate Alexander, 1951 from India, but the latter differs in the following characters: tergite 9 with lateral projections tipped with two or three spicules; outer gonostylus long and slender; inner gonostylus long and narrow, lower beak like a slender blackened rod; sternite 8 with two tufts of hair.
Etymology. This species is named after the type locality, Beibeng, Xizang, China.
Head (Figs 10,11). Mainly yellow. Vertex with velvety, dark-brown, rectangular spots near inner margin of eye. Occipital marking annular, velvety, dark brown. Face with short, linear marking. Dorsal part of rostrum including nasus brownish black. Head with brown hairs. Antenna brownish black, with dark-brown hairs, except scape and pedicel dark brownish yellow; first flagellomere 1.6 times as long as second one. Proboscis brown, with dark-brown hairs. Palpus brown, with brownish-yellow hairs.
Thorax (Figs 10,11). Mainly yellow. Pronotum mainly yellow, with dark-brown spots on lateral side. Prescutum with three black, longitudinal stripes bearing velvety margin. Scutum with two black spots bearing velvety margin. Scutellum dark brown. Mediotergite yellow, with a brown, velvety, longitudinal stripe at middle. Anepisternum and katepisternum each with a brown lower spot and black posterior margin. Anepimeron and katepimeron each with a small, pale-brown spot. Meron with black lower part. Parascutellum yellow, anatergite yellow, katatergite with black posterior margin. Legs dark yellow except tips of tibiae, femora, and tarsi dark brown. Hairs on legs brownish, except those on coxae yellow. Wing subhyaline, tinged with light brown; pterostigma brownish; vein of cell m 1 sessile (Fig. 10). Halter with yellow stem; knob dark yellow.
Distribution. China (Xizang). Remarks. This species is similar to N. distans Edwards, 1928 from Xizang, the inner gonostylus is similar, but the latter differs in the following characters: occipital marking triangular, scutellum and postnotum pale; tergite 9 without rod-like projections on posterior margin.

Diagnosis.
Pronotum yellow with a brownish spot on lateral side. Mediotergite yellow with dark-brown posterior margin (Figs 17, 19). Posterior margin of tergite 9 with a jaw-shaped protuberance; spade-shaped protuberance with two short horns at posterior margin (Fig. 22). Posterior margin of sternite 8 with meniscus-shaped protrusion (Figs 20, 23). Head (Figs 17,19). Mainly yellow. Vertex with brown spot near inner margin of eye. Occipital marking dark brown, bell-shaped, extended to top of vertex. Frontal tubercle relatively high. Dorsal part of rostrum including nasus brownish black. Hairs on head dark brown. Antenna dark brown except scape yellow and pedicel dark yellow; first flagellomere 1.4 times longer than second one. Proboscis yellow, with brown hairs. Palpus brownish grey, with brown hairs.
Thorax (Figs 17, 19). Mainly yellow. Pronotum yellow with a brownish spot on lateral side. Prescutum with three black longitudinal stripes; anterior end of lateral prescutal stripe bent outward, outer part brown. Scutum with two large, dark-brown spots. Scutellum dark yellow. Mediotergite yellow with dark-brown posterior margin. Anepisternum and katepisternum pale yellow with yellow lower part. Anepimeron pale yellow. Parascutellum pale brown; anatergite and katatergite pale yellow. Legs yellow except middle portions of femora, tips of tibiae, and tarsi dark brown; hairs dark brown, except those on coxae and trochanters yellow. Wing subhyaline, tinged with light brown; pterostigma pale brown; cell m 1 nearly sessile (Fig. 18). Halter with stem brownish grey; knob yellowish brown.
Remarks. Hypopygium of this species is very specific; no similar species.
Head (Figs 26,27). Mainly yellow. Occipital marking brown, faint. Frontal tubercle relatively high. Dorsal part of rostrum, including nasus, dark brown. Head with black hairs. Antenna dark brown except scape yellow, pedicel and first flagellomere brown; first flagellomere 1.2 times as long as second one; both ends of flagellomere obvious expansion. Proboscis mainly yellow, with black hairs. First palpal segment yellow, second one brown, with black hairs.
Thorax (Figs 26, 27). Mainly yellow. Pronotum yellow, pale brown on lateral side. Prescutum with three black longitudinal stripes; anterior end of lateral prescutal stripe bent outward, outer part brown. Scutum with four black spots. Scutellum dark yellow, with brown middle stripe. Mediotergite yellow, with brown to dark-yellow middle stripe. Anepisternum and katepisternum yellow; katepisternum with yellow lower part. Anepimeron pale yellow, lower part dark yellow. Anatergite and katatergite yellow. Parascutellum yellow. Legs yellow except tips of tibiae brown and tarsi dark brown; hairs dark brown except those on coxae dark yellow. Wing subhyaline, tinged with light brown; pterostigma slightly deepened; cell m 1 shortly petiolate (Fig. 28). Halter with stem pale brown; knob pale yellow. Abdomen (Fig. 26). Mainly yellow. Abdominal tergites with three brown longitudinal stripes. Abdominal segments 6-8 entirely dark brown to black; hypopygium mainly yellow; tergite 9 brown or yellow. Hairs on abdomen blackish or yellow.
Distribution. China (Sichuan, Yunnan and Xizang). Remarks. First record for Xizang. This species is similar to N. impigra impigra Alexander, 1935 from China (Hubei, Sichuan, Zhejiang, Fujian, Guizhou, Jiangxi), but the latter differs in the following characters: occipital marking distinct; scutellum dark brown. The hypopygium of this species is consistent with holotype, and we found that its occipital marking is variable. We think the difference between the veins is caused by the origin, which is also variable. Description. Male (n = 4): body length 10.3-10.6 mm, wing length 11.0-11.6 mm, antenna length 2.8-3.0 mm.
Parascutellum yellow. Legs yellow, except tips of femora dark yellow, tips of tibiae and tarsi dark brown; hairs brown, except those on coxae and trochanters yellow. Wing subhyaline, tinged with light brown; pterostigma brown; cell m 1 sessile, cell m 1 and cell d narrow; apices of R 5 not curving up (Fig. 36). Halter pale yellowish brown.
Abdomen (Fig. 34). Mainly yellow. Abdominal tergites each with three brown spots, lateral spots rather narrow and fused with each other; tergite 1 without spot, median spot on tergites 2 and 3 roughly rectangular, on tergites 4-8 subtriangular. Abdomen with yellow and brown hairs.

Remarks.
This new species is similar to N. korpa Alexander, 1967 from India (Sikkim), but the latter differs in the following characters: posterior vertex with three brown spots at narrowest point; projections of tergite 9 smaller, but lateral projections without spines; outer gonostylus unusually long, basally expanded.
Etymology. This species is named after the collector, Shaolin Han.

Nephrotoma nigrohalterata
Head (Figs 43,44). Mainly yellow. Vertex with round, dark-brown spot near inner margin of eye. Occipital marking dark brown, subtriangular. Face with obvious linear marking. Posterior margin of postgena brown. Dorsal part of rostrum including nasus brownish black. Head with black hairs. Antenna black with dense villi; first flagellomere 1.2 times longer than second one. Proboscis mainly yellow, with brown hairs. Palpus greyish brown, with brown hairs.
Thorax (Figs 43,44). Mainly yellow. Pronotum mainly yellow, with large, brown spots on lateral side. Prescutum with three black longitudinal stripes, middle stripe extended to scutum, anterior end of lateral prescutal stripe slightly bent outward. Scutum with two black spots. Scutellum dark brown. Mediotergite with a brown longitudinal stripe at middle. Anepisternum and katepisternum each with large black spot, posterior margin of anepisternum and katepisternum black; spot of anepisternum tilted V-shaped. Anepimeron and katepimeron each with small pale brown spot. Meron with black lower portion. Anatergite yellow, katatergite with black lower margin. Parascutellum yellow. Legs yellow, except anterior margin of coxae brown black, tips of tibiae and femora brown; hairs brownish except those on coxae yellow. Wing subhyaline, tinged  with light brown; pterostigma greyish brown; vein of cell m 1 shortly petiolate, cell d almost as long as cell m 1 (Fig. 45). Halter with stem brown; knob yellowish brown.
Head (Figs 52, 53). Mainly yellow. Vertex with brown spot near inner margin of eye. Occipital marking brown, subtriangular. Dorsal part of rostrum including nasus brown. Head with black hairs. Antennal scape yellow, pedicel pale brown, flagellum mainly dark brown except first flagellomere pale brown; first flagellomere 1.5 times longer than second one. Proboscis yellow, with brown hairs. First palpal segment greyish brown, second one yellow, with brown hairs.