New and little-known species of Tipula Linnaeus (Diptera, Tipulidae) from Laos, with a new synonym

Abstract Only seven species of the genus Tipula Linnaeus were previously known to occur in Laos. Here one new species is added to the fauna of Laos, Tipula (Nippotipula) champasakensissp. nov.Tipula (unplaced) cladomera Alexander, 1936 is designated as a synonym of T. (unplaced) reposita Walker, 1848, syn. nov. A key to species of the genus Tipula from Laos is presented.


Introduction
The genus Tipula Linnaeus is a large genus in the family Tipulidae. It is distributed worldwide with 2445 known species and subspecies, of which 1024 taxa are from the Palaearctic Region, 496 taxa from the Nearctic Region, 464 taxa from the Neotropical Region, 112 taxa from the Afrotropical Region, 356 taxa from the Oriental Region, and 30 taxa from the Australasian/Oceanian Region (Oosterbroek 2020). This genus is characterized by the following features: antenna usually 13-segmented, rarely 14-segmented, each segment dilated at base with 4-6 setae except scape, pedicel and first flagellomere; formula of tibial spurs 1-1-2, 1-2-2, 2-1-2 or 2-2-2; wings with two anal veins, A 2 usually away from inner margin, and cell a 2 broad; Rs long and originating well before end of Sc 2 ; M separated into three veins, cell m 1 petiolate; m-cu located beyond fork of M (Savchenko 1961;Joseph 1974;Savchenko 1983).
The subgenus Nippotipula Matsumura is a small subgenus in the genus Tipula. It contains 17 known species and subspecies, of which five taxa are from the Palaearctic Region, two taxa from the Nearctic Region, and 15 taxa from the Oriental Region (Oosterbroek 2020). This subgenus is characterized by the following features: formula of tibial spurs 1-2-2; R 4+5 in a straight line with the Rs (base of R 4+5 not curving); Rs long, at least twice as long as m-cu (Edwards 1931); abdomen exceeding wings; lobe of gonostylus larger than clasper of gonostylus, and with strong, dense setae.

Material and methods
The specimens were studied and illustrated with a ZEISS Stemi 2000-c stereomicroscope. Details of coloration were checked in specimens immersed in 75% ethyl alcohol (C 2 H 5 OH). Genitalic preparations of males were made by macerating the apical portion of the abdomen in cold 10% NaOH for 12-15 hours. After examination, it was transferred to fresh glycerine (C 3 H 8 O 3 ) and stored in a microvial pinned below the specimen. The specimens studied, which were collected in Laos during June 2017, are deposited in the Entomological Museum of China Agricultural University (CAU), Beijing, China.
Some type and non-type material used in this paper were borrowed from the National Museum of Natural History, Smithsonian Institution, Washington, DC, USA (USNM) and the Natural History Museum, London, UK (BMNH). Unfortunately, specimens of two species previously recorded from Laos were unavailable for study, T. vitalisi and T. laosica. Therefore, any comparisons/characters mentioned in the key and elsewhere where based on the previously published descriptions of these species.
Hypopygium (Figs 5-7). Posterior margin of ninth tergite with a shallow, Ushaped notch. Posterior margin of eighth sternite with a pair of digitiform appendages. Clasper of gonostylus complex (Fig. 7), beak with triangular, membranous dorsal lobe, dorsal crest with a sickle-shaped dorsal process, basal beak and posterior crest with short setae; face of dististyle with a slender, acute, upwardly tilted spine.
Female resembles male in head and thorax, except abdomen plump. Eighth tergite and eighth sternite black throughout with black setae. Ninth tergite, ninth sternite, and tenth tergite dark black, with black setae (Fig. 2).
Thorax (Figs 19, 21). Mainly brownish. Prescutum brownish yellow with three pale yellow stripes; median stripe broad basally with a light brown median line, lateral stripes oval, shorter than median stripe. Scutum brownish yellow, each lobe with two  pale yellow stripes. Scutellum gray-yellow. Mediotergite yellow with long brownish yellow setae. Thoracic pleuron mostly brownish throughout, except middle of pleuron bright yellow or tinged brown. Setae on thorax brownish yellow. Legs coxae and trochanters grayish yellow, femora light brown, with subterminal dark band, tibiae, and tarsi brownish. Setae on legs black except those on coxae grayish yellow. Wings brownish yellow, with dark brown spots at the origin of Rs, M, and R 4+5 . Pterostigma dark brown with some macrotrichiae, Rs relatively long; cell m 1 petiolate (Fig. 22). Halter length approximately 2.5 mm; halter stem brownish yellow, with brownish yellow setae; halter knob pale yellow (Fig. 21). Abdomen (Fig. 19). Mainly brownish yellow. Abdominal segments 1-6 brownish yellow with yellow setae; segments 7 and 8 with brown setae. Hypopygium reddish brown, with brown setae.
Hypopygium (Figs 19, 23-27). Eighth sternite extended backward, posterior margin with a deep median notch and setae; two small, triangular processes present at bottom of notch. Posterior margin of ninth tergite extended with ossified depression; middle of extension with a small spiny protrusion. Ninth sternite with dark-brown setae laterally. Lobe of gonostylus fleshy with dense, dark-brown setae on outer side and dense, black, obtuse spinules on inner side, posterior margin with a V-shaped depression. Clasper of gonostylus duck-shaped; posterior crest with longer setae.
Remarks. This new species is somewhat similar to T. (N.) coquilletti Enderlein, 1912 from Japan and T. (N.) sinica Alexander, 1935 from China (Zhejiang) in having a similarly shaped hypopygium, but it can be separated from these species by the shape of the eighth sternite and ninth tergite, posterior margin of eighth sternite with V-shaped notch which with two long triangular processes at bottom, and posterior margin of ninth tergite with a small spiny protrusion at middle. In T. (N.) coquilletti, the posterior margin of eighth sternite is without processes and V -shaped depression, and the posterior margin of the ninth tergite has a V-shaped notch. In T. (N.) sinica, the eighth sternite is without processes and V-shaped depression, and the posterior margin of the ninth tergite is extended with a sclerotized U-shaped depression.

Diagnosis.
Rs is relatively long and cell m 1 is petiolate. Tip of eighth sternite has long dense thick setae. Ninth tergite has a U-shaped depression. Lobe of gonostylus is subtriangular and posterior margin has a shallow V-shaped incision with a black sclerotized protuberance. Clasper of gonostylus is small and beak-like. Description. Male (n = 3): Body length 12-13 mm, wing length 13-14 mm, antenna length 4-4.5 mm.
Head (Figs 38, 39). Mostly brownish yellow. Dorsal part of rostrum brownish yellow, with distinct long nasus. Eyes black. Setae on head black. Antenna dark brown except scape brownish and pedicel yellow; first flagellomere longest, slightly longer than scape. Proboscis mostly brown with black setae; palpus greyish brown, with black setae.
Thorax (Figs 38, 39). Mainly brownish. Pronotum yellow with a light brown spot at middle. Prescutum yellow with three brown stripes; median stripe narrowed basally with a light brown median line; lateral stripes oval, a little shorter than median stripe. Scutum yellow, each lobe with a brown stripe. Scutellum yellow with a brown margin. Mediotergite yellow with a brown area near hind margin. Pleuron brownish yellow. Setae on thorax brownish yellow. Legs with coxae and trochanters yellow; femora light brown with dark tips; tibiae and tarsi dark brown. Setae on legs black, except those    on coxae yellow. Wings light brown; pterostigma dark brown with some macrotrichia; posterior margin of cell cua 1 as wide as base; Rs relatively long, cell m 1 petiolate (Fig. 40). Halter length approximately 2.5 mm; halter stem pale yellow; halter knob brownish gray, with brownish setae. Abdomen (Fig. 38). Mainly brownish yellow. Abdominal segments 1-5 brownish yellow with yellow setae; remaining segments dark brown with light brown setae.
Semen pump (Figs 41-43). Posterior immovable apodeme (pia) brownish yellow, rod-like, and directed backward. Compressor apodeme (ca) ginkgo-leaf-shaped and directed ventrally. Anterior immovable apodeme (aia) triangular. Remarks. Tipula (unplaced) cladomera was proposed by Alexander (1936a, as T. (Oreomyza) cladomera)) and some morphological differences were indicated. According to Alexander (1936a), males of T. (unplaced) cladomera are characterized by the following features: hypopygium with the lobe of gonostylus very large and of unusual shape, expanded outwardly, the apex with a U-shaped notch which forms two conspicuous lobes; eighth sternite with nine or ten very coarse setae on either side of midline of the caudal margin (Fig. 51;Alexander 1936a: 230;pl. 2, figs 25, 26). After comparison of the type specimens of T. (unplaced) cladomera Alexander, 1936 with T. (Vestiplex) reposita Walker, 1848 and our specimens from Laos, we found that those specimens do not have clear differences and are characterized by the same features, even though the males of T. (unplaced) cladomera have no shorter cross-vein between cell dm and cell cua 1 (Fig. 50; Alexander 1936a: pl. 1, fig. 5), and T. (Vestiplex) reposita does have shorter cross-vein between cell dm and cell cua 1 (Brunetti in Joseph 1974: 268, fig. 109). Altogether, through examining many specimens, including holotypes and paratypes, and the literature, we attribute such differences as intraspecific variation and consider these two species to be the same and T. (O.) cladomera to be a junior synonym of T. (unplaced) reposita. This species used to be placed in the Tipula subgenus Vestiplex, although in our opinion, such an arrangement is incorrect because of the unique male genital complex. Tipula (unplaced) reposita Walker, 1848 does not belong to any existing subgenus and is to be considered unplaced.