Two new species of the genus Nephrotoma (Diptera, Tipuloidea, Tipulidae) from China with a key to species from Mainland China

Abstract Nephrotoma liankangensis sp. n. and Nephrotoma pseudoliankangensis sp. n. are described from males and females collected from Henan and Yunnan provinces, China. Morphological descriptions and illustrations for the new species are provided. A key to known species from mainland China is provided. Some internal reproductive structures, including male semen pump, female vaginal apodeme and spermatheca, are described and compared. The possible usefulness of these internal reproductive structures for separating related species is analyzed. The type specimens are deposited in the animal specimen room, School of Life Sciences, Anqing Normal University, Anhui Province, China.

Introduction 15 (13) Occiput without mark (see Yang and Yang 1990: p. 122); male sternite nine without appendage at caudal margin (see Yang and Yang 1990: p. 124 (14) Flagellum dark yellow; scutum with spots brown; abdomen dark yellow (see Yang and Yang 1987: p. 243 Male sternite eight with produced appendage at caudal margin (see Yang and Yang 1991: p. 44 Yang and Yang 1988: p. 111 (44) fig. 115 Diagnosis. Antennae with flagellum light brown, pleura light yellow conspicuously patterned with white, abdominal tergites with two black lateral stripes and one brown median stripe, ninth tergite with two rounded lobes which are densely covered with black spines, posterior margin of ninth tergite not concaved at base of lobes. Description. Male (n=2): body length 9.8 mm, wing 10.5 mm, antenna 5.8 mm.
Nasus yellow with black setae, palpi black. Antennae relatively long, if bent backward extending to the first abdominal tergite, scape and pedicel yellow, flagellum 10-segmented, with the first flagellomere yellow, with the second to tenth flagellomeres light brown and enlarged at both ends, the basal enlargement black with black setae basally, subequal to the flagellomeres from which they arise. Head yellow, occipital brand brown and narrow, along the middle line of occiput (Fig. 1).
Pronotum light brown, changing into yellow in middle. Prescutum yellow with three brown stripes, median one expanded apically, not extending to the hind border, lateral stripe straight and rounded apically, extending slight beyond the middle of median stripe (Fig. 2). The median stripe lighter in coloration than lateral one, sometimes divided by a yellow line (Fig. 2). Scutum light brown, each lobe with jet-black anterior border, median area of scutum yellow (Fig. 2). Scutellum yellowish. Postnotum light brown. Pleura yellowish brown, variegated by white on anepimeron, katepimeron, meron and basal laterotergite. Halters yellowish brown throughout. Legs with coxae and trochanters yellow; femora and tibiae yellow with brown tips; tarsi dark brown. Wings transparent, cells c and sc suffused with brown; stigma oval, dark brown; wing tip narrowed and slightly suffused with light brown. Cell r1 without stigmal trichia, cell m1 petiolate (Fig. 3).
Abdomen generally yellow, the first tergite light brown, tergites two to six with a light brown median stripe and two black lateral stripes, sternites two to seven with light brown median stripe, hypopygium chiefly yellowish brown. Male hypopygium (Figs 4,5) with the ninth tergite having the median notch rounded basally, gradually narrowed to apex, separating the ninth tergite into two rounded lobes, the lobe black and densely covered with black spines (Fig. 6). Outer gonostylus lanceolate, basally widened and gradually narrowed to the end (Figs 4, 5, 7). Inner gonostylus with two black beaks (Figs 8, 9).
Female (n=2): body length 16.2 mm, wing 12.0 mm, antenna 3.2 mm. The general coloration of head, thorax and abdomen similar to that of male. Antennae relatively short, if bent backward not extending to abdomen, scape and pedicel yellow, flagellum 10-segmented, each flagellomere cylindrical, gradually shorter and slightly enlarged at base, the basal two flagellomeres yellow, three to ten flagellomeres yellowish brown with black at base.
Distribution. China (Henan). Etymology. The specific epithet is a noun 'liankang' with Latin suffix 'ensis', referring to the distribution of the new species.
Remarks. This new species is similar to N. pseudoliankangensis, as discussed below, and another Chinese species, N. sinensis (Edwards, 1916), by the coloration of the prescutum and wings, the shape of lobes on the ninth tergite and the shape of inner gonostylus. It can be easily distinguished from the latter by the prescutum not bearing a black spot on anterior portion of the lateral stripe (this black spot present in N. sinensis as described by Liu et al. 2009: 43), the ninth tergite without spiny prominence on each side of lobes (this spiny prominence on each side of lobes in N. sinensis as illustrated by Sidorenko 1999: 112), and the inner gonostylus broad apically (apical half obviously narrower than that of N. liankangensis in N. sinensis as illustrated by Sidorenko 1999: 112). Diagnosis. General coloration light yellow, antennae with flagellum black except the first flagellomere, pleura white conspicuously patterned with yellow, abdominal tergites with two black lateral stripes and one brown median stripe, ninth tergite with two rounded lobes, posterior margin of ninth tergite slightly concaved at base of lobes.
Description. Male (n=2): body length 9.6 mm, wing 11.0 mm, antenna 5.1 mm. Nasus brown with brown setae, palpi black. Antennae relatively long, if bent backward extending to the first abdominal tergite, scape and pedicel yellow, flagellum 10-segmented, with the first flagellomere yellow, with second to tenth flagellomeres black and enlarged at base and apex, each flagellomere with black setae at base, subequal to the flagellomeres where they are found. Head yellow without occipital brand (Fig. 20).
Pronotum entirely yellow. Prescutum yellow with three brown stripes, median one percurrent and expanded apically, lateral stripe straight and rounded apically, the area between lateral stripe and lateral border of prescutum suffused with brown (Fig. 21). Scutum light brown, each lobe with jet-black anterior border, median area of scutum yellow (Fig. 21). Scutellum yellowish brown. Postnotum light brown with white median stripe. Pleura white, variegated by yellow on anepisternum and katepisternum. Halters yellowish brown throughout. Legs with coxae and trochanters yellow; femora and tibiae yellow with brown tips; tarsi dark brown. Wings transparent, cells c and sc variegated with brown; stigma oval, dark brown; wing tip narrowed and slightly suffused with light brown. Cell r1 with five to six stigmal trichiae, cell m1 petiolate (Fig. 22). Abdomen generally yellow, the first segment yellow with light brown tergite, tergites two to seven with a brown median stripe and two black lateral stripes, the median stripe expanded at hind border, tergite eight entirely brownish black; sternites two to seven with light brown median stripe, hypopygium chiefly yellowish brown. Male hypopygium (Figs 23,24) with the ninth tergite having the median notch rounded and widened basally, separating the ninth tergite into two rounded black lobes, which densely covered with black spines, almost connected to each other (Fig. 25). Outer gonostylus lanceolate, basally widened and gradually narrowed to the end (Figs 23, 24, 26). Inner gonostylus with two black beaks, the dorsal side of inner gonostylus obviously extended (Fig. 27).
Aedeagal guide very similar to that of N. liankangensis, with paramere not blunt apically, the dorsal margin slightly arched, the ventral and outer margins forming an obtuse angle (Fig. 28).
Semen pump very similar to that of N. liankangensis, with posterior immovable apodeme (PIA) not bent directed dorsad at the apex in lateral view (Fig. 30); compressor apodeme (CA) fan-shaped, broader than that of N. liankangensis (Figs 29,31), with median ridge slightly expanded in lateral view, which more degenerated than that of N. liankangensis (Fig. 30); anterior immovable apodeme (AIA) more expanded than that of N. liankangensis in lateral view (Fig. 30).
Female (n=3): body length 15.8 mm, wing 13.0 mm, antenna 2.5 mm. The colouration of head, thorax and abdomen similar to those of male. Antennae relatively short, scape and pedicel yellow, flagellum 10-segmented, each flagellomere cylindrical, gradually shorter, the basal two flagellomeres entirely yellow, three to ten flagellomeres yellowish brown with black at base.
Distribution. China (Yunnan). Etymology. The specific epithet is based on the name of the related species, N. liankangensis, with the Latin prefix 'pseudo', referring to the morphological similarity of the new species to N. liankangensis.
Remarks. This new species is externally similar to N. liankangensis by the colouration of head, thorax, abdomen and wings, and the shape of inner and outer gonostyli. It can be easily distinguished from the latter by antennae with the second to tenth flagellomeres black (the second to tenth flagellomeres yellow with basal enlargement black in N. liankangensis), the occiput unpatterned (with brown median brand in N. liankangensis as shown in Fig. 20), and the inner gonostylus with the dorsal margin obviously extended (just slightly extended in N. liankangensis as shown in Figs 8,9). The new species is also similar to N. liankangensis in some internal reproductive organs, but differs from the latter in the female vaginal apodeme widened at basal two fifths, tubular and parallel at apical three fifths (vaginal apodeme widened at basal half and gradually tapered to the end in N. liankangensis as shown in Fig. 17), the spermatheca laterally with membranous extension truncate (with membranous extension angular in N. liankangensis as shown in Fig. 18), the male aedeagal guide with paramere not blunt apically (apically blunt in N. liankangensis as shown in Fig. 10), the semen pump with posterior immovable apodeme not dorsally bent (dorsally bent in N. liankangensis as shown in Fig. 13), and compressor apodeme with median ridge slightly expanded in lateral view (median ridge obviously more expanded than that of N. pseudoliankangensis in N. liankangensis as shown in Fig. 13).

Discussion
Based on morphological comparison, the characters of the vaginal apodeme, spermatheca and semen pump are uniform in different individuals of N. pseudoliankangensis and N. liankangensis. However, these structures show noticeable differences between the two species. More comparative morphological study may not only prove a high application value of the characters of these internal reproductive structures in separating relative species, but also prove the roles of these structures for phylogenetic studies as mentioned by Tangelder (1985). Moreover, although used less frequently, the characteristics of female genitalia, especially the vaginal apodeme and ninth sternite, may be helpful to effectively distinguish species in which males are difficult to collect.