Two new crane fly species of the subgenus Vestiplex Bezzi, 1924 (Diptera, Tipulidae, Tipula) from Yunnan and Sichuan, China, with a key to species in the immota species group

Abstract Two new crane fly species, Tipula (Vestiplex) gongdangensissp. nov. and T. (V.) dechangensissp. nov. are described and illustrated based on materials collected in the Yunnan and Sichuan provinces, China. A key is provided to distinguish males of the new species from those of other species in the T. (V.) immota Alexander, 1935 species group which is proposed here for the first time.


Introduction
The World fauna of the subgenus Vestiplex Bezzi, 1924 currently amounts to 176 described species, distributed throughout the Holarctic and Oriental regions (Oosterbroek 2021). The Chinese fauna of Vestiplex is richly represented, with 69 species and one subspecies (Oosterbroek 2021).
The subgenus Vestiplex can be recognized by females having a powerfully constructed and heavily sclerotized cercus, usually with a serrated ventral margin, although margins may be smooth in some of the Asiatic species (Alexander 1935(Alexander , 1965Alexander and Byers 1981). The hypogynial valve is short to rudimentary, in the shape of blades or plates, or filamentous (Starkevich et al. 2019a(Starkevich et al. , 2020. Some species of the subgenus Vestiplex have tergite 9 of the male hypopygium forming a shallowly concave and sclerotized saucer (Alexander 1935;Alexander and Byers 1981;Starkevich et al. 2020), while other species have tergite 9 divided by a pale membrane at the midline, with the posterior margin of the dorsal portion simple or bearing additional lobes, ventrally membranous or terminating in a pair of plates, sclerotized processes, armatures or flattened lobes (Alexander 1935;Alexander and Byers 1981;Men et al. 2017;Pilipenko et al. 2019;Starkevich et al. 2019a, b).
Two new species were detected while sorting and identifying specimens of Vestiplex from the Sichuan and Yunnan provinces, China. In the present paper, the new species are described and illustrated. The Tipula (V.) immota Alexander, 1935 species group is proposed here for the first time. A key to separate all known species in this species group is given.

Materials and methods
Adult crane flies were collected at ultraviolet light and with an insect net, and preserved in 96% ethanol. Specimens were studied with a Nikon SMZ800 (Nikon, Japan) and an Olympus SZ61 (Olympus, Japan) stereomicroscopes. Images were taken with a Canon EOS 80D (Canon, Japan) mounted on an Olympus SZX10 (Olympus, Japan) stereomicroscope and with a KUY NICE (KUY, China) mounted on an Olympus SZ61 stereomicroscope. The genitalia were studied after boiling in a 10% NaOH solution for 5-10 minutes.

Tipula (Vestiplex) immota Alexander, 1935 species group
The immota group can be distinguished from other T. (Vestiplex) species by tergite 9 having 1) a pair of brown, inconspicuously protruded rounded lobes dorsally, located on either side of the midline, 2) posterior margin terminating into a pair of short, heavily blackened processes and 3) membranous, brown ventral portion with additional microscopically darkened dots.
Males of the immota group can also be recognized by the following features: gonocoxite dorsally produced into a horn or spine; clasper of gonostylus terminating into an extended upper beak, dorsal crest nearly rectangular or angular, with a blackened ridge originating from the dorsal corner and a suffused black rim along dorsal surface; lower beak absent; sternite 9 with dorsal lobe of A9S short, fused basally with ventral lobe; adminiculum flattened basally and dilated, with median portion distinctly protruded. The female is known only for T. (V.) dechangensis sp. nov. and is characterized by a smooth cercus and a short, blackened, plate-like hypogynial valve.
The immota group is close to the bicornigera species group (Starkevich et al 2019a). Both groups are characterized by an armed gonocoxite, tergite 9 with additional extensions on posterior margin, and dorsal lobe of A9S reduced. The bicornigera group can also be separated by the hypertrophic ventral portion of tergite 9, the absence of protruded lobes on the dorsal surface, and posteromedian lobes having the same level of sclerotizasion as the rest of the tergal surface, not heavily blackened as in the immota species group. trivittate, distal segments, including hypopygium, dark brown; male antenna reaching base of abdomen if bent backward. Hypopygium with gonocoxite apically with a black spine that is curved at tip; tergite 9 divided at midline by a pale membrane, posterior margin with U-shaped notch, dorsal surface with pair of brown, inconspicuously protruded, rounded lobes, posterior margin terminating with a pair of black and short, wedge-shaped processes; adminiculum with a rounded preapical incision in lateral view. Female with cercus nearly straight, outer margin smooth, without visible serration, hypogynial valve in the shape of short brown plates, obtuse at apex.
Head. Yellowish, vertex and occiput yellowish with dark brown median line. Rostrum yellowish, with short nasus. Antenna 13-segmented, elongate, if bent backward reaching base of abdomen. Scape, pedicel and first flagellomere yellow; following flagellomeres basally brown, apically light brown. Each flagellomere except first slightly enlarged at base (Fig. 1). Apical flagellomere small, reduced. Verticils shorter than their corresponding segments. Palpus brownish-yellow. Thorax. Pronotum light brown, with darker median line. Prescutum and presutural scutum brownish, with four brown longitudinal stripes. Interspaces grey, median pair fused anteriorly, with anterior margins inconspicuously bordered by darker brown. Scutum grey, scutal lobes each with two brown spots. Scutellum and mediotergite grey, with dark brown median line. Pleura yellowish, thinly grey-dusted (Fig. 1). Leg with coxa and trochanter yellow; femur yellow, with darkened tip; tibia and tarsal segments dark brown; tarsal claw with tooth ( Fig. 1). Wing light brown (Fig. 2), cell sc not darker than ground colour, stigma dark brown, variegated by light areas including apical area of cell c and medial area of first cell of cell r 1 , a light band across apical area of cell r 1 , base of cells r 3 , r 4 and r 5 , and median area of discal cell; remaining light area including base and apical areas of bm. Wing venation: R 1 complete, R 2+3+4 subequal in length to R 3 , R 4 as long as Rs, R 5 curved in apical half, r-m as long as base of R 5 , discal cell narrow, at least 3 times as long as petiole of cell m 1 , cell m 1 more than 4× longer than its petiole. Halter pale yellow, knob brown basally, pale yellow apically.
Biology and distribution. The new species is known from the Dechang, located at the eastern edge of the Tibetan plateau in Sichuan Province, China (Fig. 36). Two males and three females were collected at ultraviolet light at the beginning of May, at an altitude of around 2100 m. The new species was collected in the dry valley of a small river, with slopes covered by mixed forest dominated by various broadleaved trees such as oaks (Quercus dentata Thunberg, Q. glauca Thunberg), poplars (Populus cathayana Rehder, P. simonii Carrière), elm (Ulmus parvifolia Jacquin), rhododendrons (Rhododendron brachycarpum G. Don, R. dauricum Linnaeus), and bamboos (Phyllostachys ssp., Borinda ssp., Fargesia spp.) (Fig. 21).
Etymology. The new species name is derived from the type locality, Dechang, in Sichuan, China.
Disscussion. Tipula (V.) dechangensis sp. nov. is most similar to T. (V.) gongdangensis sp. nov. in body and antenna colouration, and in the shape of the gonocoxite, the clasper of the gonostylus and the dorsal lobe of A9S. These two species can be separated by following details of tergite 9: posterior margin with U-shaped notch, black processes wedge-shaped, and posterolateral corner without extension in T. (V.) dechangensis sp. nov.; posterior margin broadly emarginated, without U-shaped notch, black processes nearly triangular, and posterolateral corner extended in T. (V.) gongdangensis sp. nov. Both species can be also separated by differences in the adminiculum, which has a preapical incision in T. Paratypes: 23 males, topotypic (AQNU), preserved in ethanol. Diagnosis. Tipula (V.) gongdangensis sp. nov. can be recognized by the following combination of characters: body yellow, abdomen with basal segments yellow, tergites trivittate, distal segments, including hypopygium, dark brown; male antenna reaching base of abdomen if bent backward. Hypopygium with gonocoxite armed with a black spine; tergite 9 divided at midline by a pale membrane, broadly emarginated at posterior margin, dorsal surface with a pair of brown, inconspicuously protruded, rounded lobes, posterior margin terminating with a pair of short, black, triangular processes. Adminiculum with median portion before apex distinctly protruded, apex curved, acute in lateral view.
Head. Yellowish, vertex and occiput yellowish, medially with narrow dark brown line. Rostrum yellowish, with short nasus densely covered with black setae. Antenna 13-segmented, elongate, if bent backward reaching base of abdomen. Scape, pedicel and first flagellomere yellow; following flagellomeres basally brown, apically light brown, producing an indistinct bicoloured appearance (Fig. 22). Each flagellomere, except first, slightly enlarged at base, segments progressively shortened and narrowed. Apical flagellomere small, reduced. Verticils shorter than their corresponding segments. Palpus brownish-yellow. Thorax. Pronotum light brown, with darker median area. Prescutum and presutural scutum brownish, with four brown longitudinal stripes. Interspaces between median and lateral stripes grey, with light and short setae. Median pair with anterior margins and inner margins on apical 1/4 suffused with black. Scutum grey, scutal lobes greypruinose, each with two brown spots. Scutellum and mediotergite grey-pruinose, with dark brown median line. Pleura yellowish, thinly dusted with brown (Fig. 22). Leg with coxa and trochanter yellow; femur yellow with tip dark brown; tibia and tarsal segments dark brown; tarsal claw with a tooth. Wing light brown (Fig. 23), cell sc darker than ground colour, stigma dark brown with a light area at base, variegated by light areas, including apical area of cell c and median area of 1 st cell of cell r 1 , a light band across apical area of cell r 1 , base of cells r 3 , r 4 and r 5 , and median area of discal cell; remaining area light, including base and apical areas of cell bm, and median and apical areas of cells cua and cup. Wing venation: R 1 atrophied in basal half, R 2+3+4 slightly shorter than R 3 , R 4 distinctly shorter than Rs, R 5 curved in apical half, r-m distinctly longer than base of R 5 , discal cell narrow, 3× as long as petiole of cell m 1 , cell m 1 more than 4× as long as its petiole. Halter with stem yellow, knob brown, with apical part lighter.
Female. Unknown. Biology and distribution. A total of 24 males were collected with insect nets around the middle of June, 2019 on Gongdang Mountain, located in the south of Bingzhongluo town of Nujiang Lisu Autonomous Prefecture, Yunnan Province (Fig. 36). The new species was collected at altitudes of approximately 2000-2400 m, in mixed mountain forest dominated by various deciduous trees and bushes (Fig. 35).
Etymology. The specific epithet refers to the type locality, Gongdang Mountain, Yunnan, China.
Discussion. Tipula (V.) gongdangensis sp. nov. and T. (V.) dechangensis sp. nov. are closely related to T. (V.) dashahensis : p. 381, fig. 1A-C) based on the shape of the clasper of the gonostylus and of the dorsal lobe of A9S, but they differ by the shape of gonocoxite, which is stout, horn-shaped in T. (V.) dashahensis and is slender, spine-shaped in T. (V.) dechangensis sp. nov. and T. (V.) gongdangensis sp. nov. The two new species can also be separated by the intermediate stripes on the prescutum and presutural scutum, which are fused in T. (V.) dashahensis and separated, except at the anterior margin, in both of the newly described species.
Key to species (male) of the immota species group