Tipula (Vestiplex) butvilai sp. nov., a new crane fly (Diptera, Tipulidae) from Yunnan, China

Abstract A new crane fly, Tipula (Vestiplex) butvilaisp. nov., is described and illustrated based on new material collected in the Nu Jiang Valley of Yunnan Province, China. The hypopygium for the most closely related species, Tipula (Vestiplex) testata Alexander, 1935, is also illustrated. A key is provided to distinguish males of the new species from those of other species in the T. (V.) bicornigera Alexander, 1938 species group.

Females belonging to the subgenus T. (Vestiplex), are characterized by having an ovipositor with a powerfully constructed and heavily sclerotised cerci and serrate outer margins, although margins may be smooth in several Asiatic species. The hypovalvae are small to rudimentary (Alexander 1935, 1965, Alexander and Byers 1981. The male genitalia are extremely polymorphic (Savchenko 1964), typically with tergite 9 forming a shallowly concave and sclerotised saucer, although some other species have their tergite 9 completely divided longitudinally by a pale membrane (Alexander 1935, Alexander andByers 1981).
A revisionary study of this subgenus on a global basis was conducted by Starkevich (2012) and a phylogenetic review of the group is ongoing. Those species with a divided tergite 9 were grouped into the following species groups according to the phylogenetic tree: Some species placements remain unresolved due to a lack of fresh material. As part of an ongoing morphological analysis, the Tipula (Vestiplex) bicornigera Alexander, 1938 species group is proposed and diagnosed herein for the first time. The new species, belonging to this group, was detected while sorting and identifying specimens of T. (Vestiplex) from China's Sichuan and Yunnan Provinces.

Materials and methods
Adult crane flies were collected at night using an ultraviolet light trap and preserved in 96% ethanol. Specimens were studied with a Nikon SMZ800 stereomicroscope. Pictures were taken with an INFINITY-1 camera mounted on a Nikon Eclipse 200 stereomicroscope and Canon EOS 80D mounted on an Olympus SZX10 dissecting microscope. Genitalia were studied after boiling them in 10% NaOH solution for 5-10 minutes.
Descriptive terminology generally follows that of Alexander and Byers (1981) and Frommer (1963) with some additions for particular features for some T. (Vestiplex). The term appendage of sternite 9 (A9S) is adopted from Mannheims (1953), and terms ventral lobe and dorsal lobe of A9S were adopted from Gelhaus (2005).
Abbreviations for institutional collections used herein: USNM United States National Museum of Natural History, Washington, DC, USA; NRC Nature Research Centre, Vilnius, Lithuania; other abbreviation: PS slide Pavel Starkevich.

Tipula (Vestiplex) bicornigera species group
The bicornigera group can be easily distinguished from other T. (Vestiplex) species by a remarkable tergite 9 with its ventral part flattened and hypertrophic (Figs 5,16). The following species, all distributed in China (Sichuan, Hubei and Taiwan), are placed in the T. (V.) bicornigera group: Tipula (Vestiplex) bicornigera Alexander, 1938, Tipula (Vestiplex) subtestata Alexander, 1938, Tipula (Vestiplex) testata Alexander, 1935 and Tipula (Vestiplex) xingshana Yang & Yang, 1997. Males of the bicornigera group can be recognized by the following features: tergite 9 divided by a pale membrane into two parts, ventral part shaped as a hypertrophic and flattened plate, its inner and posterior margin blackened, and microscopically roughened; each half of dorsal part of tergite 9 with a posterior lobe on the posterior margin or with an additional posteromedial lobe which is covered with setae and pointed caudad; gonocoxite dorsally produced into a black spine; sternite 9 with A9S dorsal lobe usually reduced into a small triangular or rod-shaped sclerite , or narrow and distinct in case of T. (V.) butvilai sp. nov. Mesonotal prescutum golden yellow with three olive-brown stripes that are poorly defined against the background; femur without preapical yellow ring; inner gonostylus with small lower beak and dorsal crest rounded (Fig. 19); dorsal lobe of A9S in the shape of a short process (Fig. 20) .....Tipula (Vestiplex) testata Alexander, 1935 -Mesonotal prescutum yellowish with four olive-yellow stripes that are narrowly bordered by yellow; femur with yellow preapical ring (Fig. 1); inner gonostylus without lower beak; dorso-median margin with blackened tooth; dorsolateral margin in the shape of blackened obtuse outgrowth; dorsal crest nearly rectangular (Fig. 8); dorsal lobe of A9S long and narrow (Fig. 4)  Diagnosis. Among other members of T. (V.) bicornigera group T. (V.) butvilai sp. nov. can be recognized by yellow body, elongate antennae which if bent backward reach the base of the abdomen, brown flagellum and femur with a preapical yellow ring. Dorsal portion of tergite 9 posteriorly with a pair of oval lobes. Appendage of sternite 9 with dorsal lobe blackened, long and narrow. Sternite 8 provided with long setae.
Thorax. Pronotum yellow. Mesonotal prescutum, yellowish, with 4 olive-yellow longitudinal stripes, narrowly bordered by yellow and median pair separated by brownish interspace. Scutum yellow, scutal lobes each with two olive-yellow spots bordered by yellow. Scutellum and mediotergite yellow with dark median line. Pleura yellow. Leg with coxa and trochanter yellow; femur brown with broad preapical yellow ring, tip dark brown; tibia and tarsal segments dark brown; tarsal claw with tooth. Wing (Fig. 1) yellowish-brown, cells c and sc slightly darker than ground color; stigma brown; Rs suffused with dark brown at origin point and the level of its branch; discal cell transparent with the exception of outer end which suffused with brown; apical half of cells r 3 , r 4 and r 5 , and entire cells m also suffused with brown, some large hyaline areas at cells cup and a 1 . Venation: R 1+2 entire, discal cell narrow, elongated, petiole of cell m1 distinctly shorter than discal cell. Halter pale yellow with brown knob.
Biology and distribution. Two males and three females were collected during mid May, 2018. All were collected at ultraviolet lights over two nights in a Nu Jiang (Salween) river valley in the northwestern part of China's Yunnan Province bordering North Myanmar (Kachin State). The new species was collected at altitudes of approxi-mately 2100 meters in mixed mountain forest, dominated by various deciduous trees, bamboo and bushes (Figs 21-22).
Discussion. Tipula (V.) butvilai sp. nov., is closest to T. (V.) testata (China, Sichuan) based on the shape of the male hypopygium. Both species are characterized by their hypertrophied ventral portion of tergite 9 and a pair of lobes on posterior margin of dorsal portion of tergite 9 but can be easily separated by the shape of the appendage of sternite 9, inner gonostylus and details of tergite 9. They can also be separated by the yellow preapical ring on the femur which is present in T.  fig. 30) and Tipula (Vestiplex) xingshana Yang & Yang, 1997(China, Hubei;Yang andYang 1997, p. 1438, fig. 3a-c) which all share a hypertrophied ventral portion of tergite 9, but can be separated by the shape of posterior margin of the dorsal portion of tergite 9, which includes two pairs of lobes.