Triogma kuwanai (Alexander, 1913)

Kolcsar, Levente-Peter, Paramonov, Nikolai, Imada, Yume, Kato, Daichi, Gamboa, Maribet, Shinoka, Dai, Kato, Makoto & Watanabe, Kozo, 2022, Notes on the taxonomic status and distribution of some Cylindrotomidae (Diptera, Tipuloidea), with emphasis on Japanese species, ZooKeys 1083, pp. 13-88 : 13

Triogma kuwanai (Alexander, 1913)

Figs 4G , 5G, H , 31B , 36 , 37 , 38

Triogma kuwanai limbinervis Alexander, 1953, syn. nov.

Triogma nimbipennis Alexander, 1941, syn. nov.

Liogma kuwanai in Alexander 1913: 294-295, 321-322: illustration, original description; Alexander 1920: 15-16: female description.

Triogma kuwanai in Alexander 1928: 12: distribution, illustrations, comb. nov.; Esaki 1950: illustration; Alexander 1953a: 56: faunistic records; in Takahashi 1960: 81: distribution; Nakamura 2001: 23-29: identification key, illustration, distribution, faunistic records; Nakamura 2005: 685: illustration; Oosterbroek 2020 (since 2018): taxonomic status. Imada 2020: biology and ecology of larvae.

Triogma kuwanai kuwanai in Ishida 1955: 76-77: distribution; Sidorenko 1999: 68-70: identification key, illustration, distribution; Paramonov 2006: 888-889: identification key, illustration, distribution; Nakamura 2014: 54: distribution; Kato and Suzuki 2017: 16: faunistic records, distribution.

Triogma kuwanai limbinervis ssp. n. in Alexander 1953a: 56-57: original description, illustration; Alexander, 1953b: 77: distribution; Takahashi 1960: 82: distribution; Sidorenko 1999: 68-70: identification key, illustration, distribution; Paramonov 2006: 888-889: identification key, distribution; Nakamura 2014: 54: distribution.

Triogma limbinervis in Oosterbroek 2020 (since 2018): taxonomic status.

Triogma nimbipennis in Alexander 1941: 407-408: original description, illustration, comparison; Yang 1991: information about type material; Sinclair and Dorchin 2010: 80: information about type material; Alexander and Alexander 1973: 69: catalogue, distribution; Oosterbroek 2020: taxonomic status.

Type material examined.

Triogma kuwanai limbinervis Alexander, 1953: Paratype: Japan • ♀; Kochi, Tosa, Nisikawa, Mt. Yanase; alt. 800 m; 4 May. 1951; R. Takahashi leg.; USNM.

Triogma nimbipennis Alexander, 1941: Paratypes: China • ♂; Kuatun (Guadun), Fukien (Fukijen); 2500-3000 m; 23 Apr. 1938; • 2 ♀; same locality; 27 Apr. 1938 - 28 Apr. 1938; • 1 ♀; same locality; 27 Apr. 1938; Klapperich leg.; ZFMK.

Non-type material examined.

Triogma kuwanai kuwanai (Alexander, 1913): Japan • 1 ♂; Aomori, Hirosaki, Koguriyama, Inekari River; 40.53658°N, 140.48701°E; alt. 170 m; 24 May. 2013; • 1 ♂; same locality; 25 May. 2013; • 1 ♀; same locality; 28 May. 2013; D. Kato leg.; BLKU. • 2 ♂; Aomori, Nakadomari, Osawanai, Osawanai Pond; 40.94641°N, 140.46231°E; alt. 35 m; 15 May. 2014; D. Kato leg.; BLKU. • 1 ♂; Aomori, Nishimeyamura, Hirasawa River; 40.48729°N, 140.31335°E; alt. 710 m; 4 Jun. 2013; D. Kato leg.; BLKU. • 1 ♂; Aomori, Towada, Okuse, Tsutanuma Path; 40.59084°N, 140.95705°E; alt. 468 m; 23 May. 2014; D. Kato leg.; BLKU. • 1 ♂; Ehime, Iyo, Mt. Saragamine; 33.72°N, 132.89°E, 8 May. 1949; M. Miyatake leg.; EUMJ. • 1 ♀; Ehime, Komi, Yanadani; 33.55°N, 133.01°E; 6 May. 1994 - 8 May. 1994; Ohbayashi, Nishino, Okada le.; EUMJ. • 1 ♀; Ehime, Matsuyama, Misaka-toge; 33.71°N, 132.85°E; 3 May. 1951; Yano T. leg.; EUMJ. • 1, sex unknown; Ehime, Matsuyama, Sugitate; 33.84°N, 132.79°E; 8 Ap. 1950; M. Miyatake leg.; EUMJ. • 1 ♀; Ehime,?Matsuyama, Shichidori; 33.84°N, 132.79°E; 3 May. 1952; Ide leg.; EUMJ. • 1 ♂; Ehime, Saijo, spring and mosses rocks; 33.75504°N, 133.15377°E; alt. 1480 m; 5 Jun. 2019; L.-P. Kolcsár leg.; CKLP. • 1 ♂; Fukuoka, Fukuoka, Sawara-ku, Itaya, Mt. Sefuri; 33.43811°N, 130.36673°E; alt. 970 m; 2 May. 2015; D. Kato leg.; BLKU. • 1 ♂; Ishikawa, Hakusan, near to Hakusan National Park; 36.25869°N, 136.72558°E; 678 m; 27 May. 2015; M. Kato leg.; CYI. • 1 ♂, 1 ♀; Nagano, Ueda, Sanada-machi, Irikaruizawa; 36.47441°N, 138.25481°E; alt. 777 m; 16 May. 2012; D. Kato leg.; BLKU. • 1 ♂; Oita, Kokonoe, Tano; 33.11621°N, 131.23541°E; alt. 1150 m; 7 May. 2016; D. Kato leg.; BLKU. • 1 ♂; Okayama, Maniwa, Hiruzen-Kamifukuda, Nawashirodani-gawa River; 34.08837°N, 133.87994°E; alt. 600 m; 30 Apr. 2016; D. Kato leg.; BLKU. • 2 ♂, 1 ♀; Saga, Karatsu, Kyuragi-Hirano, Mt. Sakurei; 33.35701°N, 130.07038°E; alt. 862 m; 26 Apr. 2015; D. Kato leg.; BLKU. • 1 ♀; Saitama, Saitama; 35.88°N, 139.26°E; 29 May. 1919; R. Takahashi leg.; USNM. • 2 ♂, 1 ♀; Shizuoka, Shizuoka, Ikawa-touge; 35.24094°N, 138.28156°E; alt. 1471 m; 10 May. 2015; M. Kato leg.; •1 ♂; same locality; 18 May. 2016; Y. Imada leg.; CYI. • 1 ♂; Tokushima, Awa, Mt. Tsurugi; 33.87°N, 134.11°E; 31 May. 1950; Issiki-Ito leg.; USNM. • 2 ♂; Tokushima, Higashimiyoshi, Higashiyama, Ogawadani River; 34.08837°N, 133.87994°E; alt. 340 m; 21 Apr. 2014; D. Kato leg.; BLKU. • 1 ♂; Tokushima, Miyoshi, Higashiiya-Ochiai, around Matsuogawa Dam; 33.96478°N, 133.93908°E; alt. 900 m; 30 Apr. 2016; D. Kato leg.; BLKU. • 1, sex unknown; Tokyo, Meguro; 35.62°N, 139.7°E; 8 Apr. 1919; R. Takahashi leg.; USNM. • 1 ♂; Tokyo, Mt. Mitake; 35.78°N, 139.14°E; 10 May. 1931; B. Oda leg.; USNM. • 1, sex unknown; Tokyo, Tokyo; 35.67°N, 139.69°E; 8 Apr. 1930; R. Takahashi leg.; USNM. • 1 ♂; Tottori, Kurayoshi, Sekigane-cho-Nozoe, Mt. Karasuga; 35.35352°N, 133.58577°E; alt. 1000 m; 17 May. 2015; D. Kato leg.; BLKU.

Triogma kuwanai limbinervis Alexander: Japan • 7 ♂ 1 ♀; Ehime, Matsuyama, small ruderal streem; 33.86328°N, 132.77157°E; alt. 125 m; 31 Mar. 2019; L.-P. Kolcsár leg.; CKLP. • 2 ♀; Ehime, Matsuyama, ruderal forest and orange plantation; 33.86041°N, 132.76552°E; alt. 84 m; 6 Apr. 2019; L.-P. Kolcsár leg.; CKLP.

Redescription.

Head. Rugose; ground colouration dark brown to black, with very intense greyish pubescence (Fig. 36B, C ). Rostrum moderately long, with few short hairs; palpus greyish black, five segmented; last segment 1.4-1.6 × longer than penultimate in male, 1.2-1.3 × in female. Scape cylindrical, rugose, ~ 2 × as long as pedicel; pedicel ovate; flagellum 14 segmented monochrome greyish black (Figs 4G , 36B, D ). Male flagellomeres, except ultimate, expanded ventrally, covered with dense whitish grey sensilla, denser ventrally; ultimate flagellomere cylindrical, with several sensilla (Figs 4G , 36B ); female flagellomeres 1-5 or 6 extended ventrally, remaining flagellomeres fusiform to cylindrical; flagellomeres 1-10 or 11 bearing sparse whitish grey sensilla mostly on ventral side (Figs 4G , 36E ). Flagellomere with two long verticels on dorsal surface, two short on lateral face, and two short on ventral side; first flagellomere always bearing additional 1-4 verticels.

Thorax. Ground colouration dark brown to black, with very dense and intensive grey pruinosity, thorax appearing grey (Fig. 36A-C ). Pleural area, wing base, and halter yellow to yellowish brown (Fig. 36B ). Anterior part of mesonotum with rugose sutures (Fig. 36C ); lateral margin of scutum rugose (Fig. 36A, B ). Anterior half of mediotergite rugose (Fig. 36B ). Katepisternum and metakatepisternum weakly rugose (Fig. 36B ). Trochanter yellow to pale brown; femur gradually darkening apically, basally yellowish, apically black; tibia and tarsus uniformly black (Fig. 36A ). Wing hyaline, tinged with pale brown; membrane with interference patterns, visible with dark background (Fig. 36A ); pterostigma brown; veins yellow at base of wing, apically brownish; three branches of M reaching wing margin; M1 at same level as M1+2, cell a2 less than 6 × longer than wide (Fig. 5G, H ); small, weakly infuscate areas around base and fork of Rs, at crossvein r-m (if present), at base of M1+2, at crossvein m-cu, M2, and crossvein m-m. Note: the early spring specimens from Shikoku Island have more intensive wing pattern (Fig. 5H ), than the later spring specimens, or specimens collected in the other part of Japan (Fig. 5G ). The pattern is more intensive in the living specimens, less prominent in the dead ones, and became paler after time.

Abdomen. Grey with reddish tinge, caudal half of tergites and sternites 8 and 9 darker. Abdominal plaques (external remnants of attachment sites of muscles in the pupa) shiny, punctuated (Fig. 36A ).

Male terminalia: Reddish grey, directed caudally (Fig. 36A ). Tergite 9 fused with gonocoxite at base, fusion suture present (Fig. 37C ); tergite 9 with laterally directed, ear-like lobes in dorsal view (Fig. 37A ), triangular or bird-head-shaped laterally (Fig. 37C ); additional two very small, triangular lobe on posterior margin of tergite 9. Sternite 9 fully membranous (Fig. 37B ). Gonocoxite large 1.5-1.6 × longer than tergite 9, without evident ventral lobe (Fig. 37B, C ), small protuberance on ventral margin of gonocoxite in some specimen rarely present (Fig. 37C see arrow). Gonostylus simple, generally tapering to distal end (Fig. 37A, C ). Aedeagus complex very large, 1.5-1.7 × longer than gonocoxite (Fig. 37D-F ); ejaculatory apodeme and sperm pump large, not covered by paramere in lateral view (Fig. 37D-F ); interbase simple, tip rounded or sharp, with small lobe dorsally in lateral view (Fig. 37F ); dorsal lobe between interbases, membranous, bubble-like; sperm ducts branching from elongation of sperm pump, area darkened (Fig. 37F ); aedeagus 2 × as wide as interbase in lateral view; directed ventrally then turned dorsally, almost turning back anteriorly (Fig. 37F ); trifid, medial branch shorter than lateral branches (Fig. 37D-E ); tips of branches widened and flattened (Fig. 37D-F ).

Female terminalia: Cercus and hypopygial valve pale brown (Fig. 36E ). Tergite 8, ~ 1.5 × larger than tergite 9 in lateral view (Fig. 38B ); very broad in dorsal view, not divided medially (Fig. 38A ). Tergite 9 triangular in lateral view, with a small round lobe at middle, with few longer setae (Fig. 38A ). Triangular sclerites of tergite 10 variable in size (Fig. 38A ), in some specimens partly fused with tergite 10. Cercus simple, tip rounded or weakly pointed; dorsal margin weakly rugged, formed by small pyramidal teeth (Fig. 38A, B ). Hypogynial valve long, blade-like, longer than cercus; with pit at base, holding lateral lobes of male tergite 9 during copulation (Fig. 38B ). Common spermathecal duct short; spermathecal ducts wide, carrot-shaped, suddenly narrow; inner wall rugged (Fig. 38C ); three round spermathecae, with very narrow duct (Fig. 38D ).

Distribution.

Japan (Fig. 31B ) (Hokkaido I, Honshu I, Shikoku I, and Kyushu I) ( Oosterbroek 2021). Distribution records of Triogma kuwanai limbinervis (Shikoku I) and T. nimbipennis transferred to Triogma kuwanai (China: Zhejiang and Fujian).

Comments.

Alexander (1953a) described the subspecies, Triogma kuwanai limbinervis , from Shikoku Island, of which wing markings in some individuals are more conspicuous than those of T. k. kuwanai . In the original description, Alexander noted, "there is evidence of mergence with the typical form - Triogma kuwanai kuwanai -, where the wings are unpatterned or virtually so" ( Alexander 1953a). Triogma k. limbinervis has been referred to as the T. limbinervis in the CCW (since 2018) due to its sympatric occurrence with Triogma kuwanai in Shikoku Island. This study suggests that wing markings, the diagnostic character of T. k. limbinervis (Fig. 5H ), appear only in early spring specimens from Shikoku and Kyushu Islands, but do not after early spring in later specimens. It is also observed that wing marking turns paler over time. Some specimens from northern Honshu occasionally have pale wing markings, as well, suggesting variation. These two subspecies do not significantly differ in terms of male and female terminalia, and were not distinguished as different by the barcode sequences. Triogma k. limbinervis syn. nov. is therefore synonymised with Triogma kuwanai . Another closely related species T. nimbipennis Alexander, 1941, was described from China (Zhejiang and Fujian) ( Alexander 1941). This species is quite similar to T. kuwanai , and shows a subtle difference in the colour tint: particularly, the wings of T. nimbipennis are darker than those of T. kuwanai . Alexander (1941) mentioned that T. nimbipennis can be considered as a subspecies of T. kuwanai . After the morphological comparison of the type specimens of T. nimbipennis with T. kuwanai , the two species were found not to differ in genital structure, and so T. nimbipennis syn. nov. is proposed as a junior synonym of Triogma kuwanai .

Figures

Figure 4. Antennae A Cylindrotoma distinctissima (Meigen, 1818) B Diogma caudata Takahashi, 1960 C Diogma glabrata (Meigen, 1818) D Liogma mikado (Alexander, 1919) E Liogma brevipecten Alexander, 1932 F Liogma serraticornis Alexander, 1919 G Triogma kuwanai (Alexander, 1913). Scale bar: 1 mm.

Figure 5. Wing A Cylindrotoma distinctissima (Meigen, 1818) B Diogma caudata Takahashi, 1960 C Diogma glabrata (Meigen, 1818) D Liogma mikado (Alexander, 1919) E Liogma brevipecten Alexander, 1932 F Liogma serraticornis Alexander, 1919 G Triogma kuwanai (Alexander, 1913) of " Triogma kuwanai " form H Triogma kuwanai (Alexander, 1913) of " Triogma limbinervis " form.

Figure 31. Occurrence data in Japan and surrounding areas of A Liogma serraticornis Alexander, 1919 B Triogma kuwanai (Alexander, 1913). Red dots indicate locations of investigated specimens, white dots indicate approximate locations of literature data.

Figure 36. Triogma kuwanai (Alexander, 1913) A habitus of male, lateral view (colouration of wings is artefact) B head and thorax of male, lateral view C head and thorax, dorsal view D head of female, lateral view E female terminalia, lateral view.

Figure 37. Male genital structures of Triogma kuwanai (Alexander, 1913) A terminalia, dorsal view B terminalia, ventral view C terminalia, lateral view, arrow indicating shape variability of gonocoxite margin D aedeagus complex, dorsal view E aedeagus complex, ventral view F aedeagus complex, lateral view.

Figure 38. Female genital structures of Triogma kuwanai (Alexander, 1913) A terminalia, dorsal view B terminalia, lateral view C sternite 8, hypogynial valve, genital fork, and sperm ducts, inner dorsal view D spermathecae.