Cylindrotoma distinctissima (Meigen, 1818)

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

Cylindrotoma distinctissima (Meigen, 1818)

Figs 3 , 4A , 5A , 6 , 7 , 8A

Tipula brevicornis (Zetterstedt, 1838)

Cylindrotoma tenebrarum Krogerus, 1937

Cylindrotoma distinctissima borealis Peus, 1952

Cylindrotoma japonica Alexander, 1919, syn. nov.; Alexander 1919: 344-345: original description; Alexander 1924: 595: faunistic records; Alexander 1928: 9: distribution, illustrations; Esaki 1950: 1513: illustration; Ishida 1955: 77: distribution; Takahashi 1960: 81: distribution; Alexander 1966: 122: distribution, faunistic records; Sidorenko 1999: 68-70: identification key, illustration, distribution; Nakamura 2001: 23-29: identification key, illustration, distribution, faunistic records; Pilipenko and Sidorenko 2004: 12 faunistic records; Boldgiv 2006: phylogeny, faunistic records; in Paramonov 2006 as Cylindrotoma distinctissima japonica : 888: stat. nov., identification key, illustration, distribution; Gelhaus et al. 2007: 64 comparison; Sasakawa 2008: 131: faunistic records; Nakamura 2014: 54: distribution; Kato and Suzuki 2017: 16: faunistic records, distribution; Imada 2020: biology and ecology of larvae.

Cylindrotoma distinctissima alpestris Peus, 1952, syn. nov.: Peus 1952: original description.

Type material examined.

Cylindrotoma japonica Alexander, 1919: Paratype. Japan • ♀; Saitama Pref., Saitama; 31 May 1919; R. Takahashi leg.; USNM.

Non-type material examined.

Cylindrotoma distinctissima distinctissima (Meigen, 1818): Finland • 1 ♂; Vieremä, Mammonhauta; 63.924404°N, 26.869023°E; alt. 135; 18 Jun. 2008 - 13 Jul. 2008; J. Salmela leg.; CKLP. Russia • 1 ♂, 1 ♀; Krasnodar Krai, Apsheronsky District, Mezmay Settlement, Kamyshanova polyana, Mezmaika River; 44.16989°N, 40.05181°E; alt. 1200 m; 11 Jun. 2004; N.M. Paramonov leg.; CKLP.

Cylindrotoma japonica Alexander, 1919: Japan • 1 ♂; Mt. Shirouma Alps, 36.78°N, 137.7°E; 8 Aug. 1931; J. Machida leg.; USNM. • 1 ♀; Aomori, Towada, Sakura Spa, Okuse; 40.627315°N, 140.909831°E; alt. 854 m; 21 Jun. 2014, D. Kato leg.; BLKU. • 1 ♂, 1 ♀; Aomori, Nishimeyamura, Okawa Path, Kawaratai; 40.500625°N, 140.204058°E; alt. 300 m; 18 Sep. 2013; D. Kato leg.; BLKU. • 1 ♂, reared from larva; Gifu, Takayama, Nigorikawa; 36.0545°N, 137.55818°E; 1375 m; larva collected: 5 Aug. 2015, emerged: 26 May. 2015; M. Kato leg.; CYI. • 1 ♂; Gifu, Mt. Norikura, Japanese Alps; 36.12°N, 137.5°E; 26 Jun. 1929; J. Machida leg.; USNM. • 1 ♀; Hokkaido, Sapporo, Minami-ku, Jozankei, trail of Mt. Sapporo; 42.92392°N, 141.17688°E; alt. 450-860 m; 3 Sep. 2018; D. Kato leg.; BLKU. • 2 ♂, 3 ♀; Hokkaido, Higashikawa, Asahidake, River Yukomabetsu; 43.65226°N, 142.80229°E; alt. 1120 m; 23 Jul. 2019; L.-P. Kolcsár leg.; CKLP. • 2 ♂; Hokkaido, Higashikawa, Asahidake; 43.65582°N, 142.82608°E; alt. 1100-1500 m; 24 Jul. 2019; L.-P. Kolcsár, leg.; CKLP. • 1 ♂; Hokkaido, Ashoro, Meakan Moutain, small sandy/muddy stream; 43.3907°N, 143.96821°E; alt. 365 m; 27 Jul. 2019; L.-P. Kolcsár leg.; CKLP. • 1 ♀; Iwate, Hachimantai, Toshiti Spa; 39.94253°N, 140.86804°E; alt. 1344 m; 3 Aug. 2013; • 1 ♀; same locality; 1 Jul. 2014; • 1 ♂; same locality; 5 Aug. 2014; • 2 ♀; same locality; 20 Sep. 2014; • 1 ♀; same locality; 5 Aug. 2015; D. Kato leg.; BLKU. • 3 ♂; Nagano, Matsumoto, Azumi, Mt. Norikura, near Kuraigahara-Sansou; 36.11987°N, 137.5692°E; alt. 2370 m; 22 Jul. 2016; D. Kato leg.; BLKU. • 1 ♂; Nagano, Ueda, Daimyozin stream, Sugadaira MRC; 36.51992°N, 138.3539°E; alt. 1315 m; 27 Aug. 2012; D. Kato leg.; BLKU. • 2 ♂; Nagano, Sakae-mura, Sakai, Koakazawa-gawa River; 36.85352°N, 138.66358°E; alt. 1320-1600 m; 19. Sep. 2019; D. Kato leg.; BLKU. • 1 ♂; Nagano, Chino, Shibunoyu; 36.03582°N, 138.32771°E; alt. 1863 m; 21 Jul. 2013; M. Kato leg.; CYI. • 2 ♂; Nagano, Miyada, Kisokomagatake; 35.76917°N, 137.8357°E; alt. 1683 m; 13 Aug. 2013; M. Kato leg.; CYI. • 1 ♂; Nagano, Matsumoto, Kamikouchi; 36.20966°N, 137.60662°E; alt. 1320 m; 3 Aug. 2014; M. Kato leg.; CYI. • 1 ♀; Niigata, Yuzawa, Mitsumata, Mt. Naeba; 36.85616°N, 138.71041°E; alt. 1500-1900 m; 8 Aug. 2019; D. Kato leg.; BLKU. • 1 ♂; Niigata, Kurokawa, Echigo; 38.05°N, 139.47°E; 19 May 1954; B. Kintaro leg.; USNM. • 1 ♀; Okayama, Maniwa, Hiruzen-Shimotokuyama; 35.32931°N, 133.59725°E; alt. 784 m; 17 May. 2015; D. Kato leg.; BLKU. • 2 ♀; Tokyo, Tokyo, Akiruno, rocky river and stream; 35.74766°N, 139.18466°E; alt. 288 m; 11 May. 2019; L.-P. Kolcsár leg.; CKLP. • 1 ♂; Tokyo, Tokyo, Mitake; 35.78°N, 139.14°E; 10 May. 1931; B. Oda leg.; USNM. • 1 ♂; Toyama, Kurobegoro; 36.38°N, 137.47°E; 8 Aug. 1931; Imanishi leg.; USNM. • 1 ♀; Yamagata, Yonezawa, Shirabu-onsen; 37.77646°N, 140.11964°E; alt. 888 m; 26 Jun. 2015; Y. Imada leg.; CYI. Russia • 1 ♂; Saghalien [Far East, Sakhalin Oblast], Shimizu; 1922.07.27, T. Esaki leg.; USNM.

Redescription.

Colouration very variable, base colour whitish yellow to dark orange, with pale brown to black markings.

Head. Vertex and occiput with dark area, size variable among specimens, larger on " Cylindrotoma borealis " and " Cylindrotoma japonica " form; yellowish around eye (Fig. 3C, D, F ). Rostrum short, yellow to brown, without nasus, but with tuft of hairs (Fig. 3F, E ). Palpus five segmented, last segment 2 × longer than penultimate segment. Antenna yellowish brown to black (Fig. 3F, E ); scape short, as long as wide; pedicel short, subspherical to drop-shaped; flagellum 14 segmented (Fig. 4A ). Flagellar segments simple in both sexes, not expanded ventrally, covered with dense, whitish setae (sensilla), especially in ventral side (Figs 3E, F , 4A ); sensilla less dense in female; first flagellomere longer than second in both sexes; verticels black, relatively long.

Thorax. Whitish yellow to dark orange, with contrasting black marks. Cervical sclerites brown to black. Pronotum pale in middle, darker laterally (Fig. 3B, C, D ). Mesonotal pattern variable, from three longitudinal, pale brown (" Cylindrotoma alpestris " form) to black (the typical " Cylindrotoma distinctissima " form Fig. 3C ) markings to one large patch (" Cylindrotoma japonica " form Fig. 3D ); longitudinal mesonotal suture distinct, formed by deep groove (Fig. 3C, D ). Scutellum yellow, triangular (Fig. 3C, D ). Mediotergite yellow, posterior part black (Fig. 3B ). Anepisternum and katepisternum separated, both darker ventrally (Fig. 3B ). Katatergite yellow, black above posterior spiracle, with creases. Coxa base yellow to pale brown, apically yellow, trochanter yellowish (Fig. 3B ); femur and tibia yellowish, with distinct and wide, black ring at tip; tarsus uniformly black. Stem of halter yellow, knob usually darker. Wing hyaline, with yellowish brown to brown tinge; veins brown to black; pterostigma brown to black (Fig. 5A ); wing membrane with interference patterns, visible with dark background (Fig. 3A ). Four branches of M reaching wing margin. Cell a2 less than 6 × longer than wide.

Abdomen. Yellow (" Cylindrotoma alpestris " form) to almost black (" Cylindrotoma japonica " form); gradually lightening caudally, without clear pattern or with narrow longitudinal line medially.

Male terminalia. Black, directed dorsally (Fig. 3A ). Tergite 9 partly fused with gonocoxite (Fig. 6C ). Caudal margin of tergite 9 with deep V-shaped notch at middle (Fig. 6A ); posterior edge of tergite 9 forming dorsal and ventral portion in lateral view (Fig. 6C ), shapes variable among specimens. Gonocoxite fused with sternite 9 (Fig. 6B, C ); gonocoxite with ventral crescent-shaped lobe (Fig. 6A, B : vl); apical lobe of gonocoxite (al) prominent, well separated, directed inward; both ventral and inner lateral margins sclerotised, shape variable (Fig. 6A, D, E ). Gonostylus undivided; twisted, widening in caudal view, shape variable among and within population(s) (Fig. 6F , Japan; Fig. 6G , Finland). Interbase small, without membranous or sclerotised lobe between interbases (Fig. 6H, I ). Aedeagus dorsoventrally flattened, gently curved dorsally (Fig. 6J ), gradually narrowing to tip, shape variable among and within population(s) (Fig. 6H, I, L , Japan; Fig. 6M , Finland); tip divided into three short, nearly equal tubes in last 1/4 of its length (Fig. 6L, M ). Spines on lateral branch of aedeagus small, indistinct (Fig. 6K ).

Female terminalia. Brown to black, strongly sclerotised (Fig. 3G ). Tergite 8 separated in middle by membranous area (Fig. 7A ). Tergite 9 larger than tergite 8 in lateral view (Fig. 7B ). Tergite 10 with elongated Y-shaped projection, shape variable among specimens (Fig. 7A , Japan; Fig. 7C , Russia (Krasnodar Krai), Fig. 7D , Finland). Cercus with serrate, cutting edge on inner-dorsal surface (Fig. 7A, B ). Hypogynial valve on dorsal side with bulbous or triangular projection near middle, shape variable within specimens (Fig. 7B, F ); distal part of hypogynial valve narrowing to tip. Three, relatively large spermathecae present, diameter ~ 0.15-0.2 of wide of sternite 8; duct of spermatheca straight or curved (Fig. 7I, J ). Sperm ducts simple, without darkened areas (Fig. 7H ). Sternite 10 with a small notch at tip, less sclerotised at midline (Fig. 7G ).

Distribution.

Widely distributed species in Palearctic, known from: Austria, Belarus, Belgium, Bulgaria, Croatia, Czech Rep., Denmark, Estonia, Finland, France, Germany, Great Britain, Hungary, Ireland, Italy, Kazakhstan, Lithuania, Luxembourg, Mongolia, Netherlands, Norway, Poland, Romania, Russia (North European territory, Central European territory, South European territory, West Siberia (Altay), Far East (Kamchatka Krai, Primorsky Krai, Sakhalin Oblast (incl. Kuril I), Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Ukraine, and Turkey ( Paramonov and Lobkova 2013; Devyatkov 2021; Oosterbroek 2021). Distribution records of C. japonica transferred to C. distinctissima : Mongolia and Japan (Hokkaido I, Honshu I, and Kyushu I) (Fig. 8A ).

Comments.

The species was originally described 250 years ago from Europe, where it is among the most widespread of cylindrotomines. The colour polymorphisms of C. distinctissima have been described as separate species or subspecies. Peus (1952) separated three subspecies, the nominate subspecies C. d. distinctissima (Meigen, 1818), widespread in Europe, C. d. borealis Peus, 1952 from Norway, and C. d. alpestris Peus, 1952 from Italian Alps. Later, Cylindrotoma d. borealis was raised to species rank based on the generally darker habitus and slightly different genital characters (Salmela and Autio 2007). As the COI gene sequence’s genetic distance between C. d. distinctissima and C. borealis was low, the species was later synonymised with C. d. distinctissima (Salmela 2013). In our ML tree, C. borealis sequences were also not separated from C. d. distinctissima sequences. Cylindrotoma d. alpestris was treated as species in CCW (2018-2021), because it showed the sympatric distribution with C. d. distinctissima in Alps (Italy). This subspecies was designated based on very pale colouration, compared with the nominative subspecies, but the male terminalia does not show any differentiation, which was highlighted in the original description by Peus (1952). Peus noted that this subspecies maybe just a local colour variation, as Cylindrotoma specimens showed colour polymorphisms, especially in mountain specimens (as noted by the personal experience of N. Paramonov), but there is no genital differentiation between the two species, and therefore we synonymise C. d. alpestris syn. nov. with C. distinctissima .

Another species related to C. distinctissima was described from Japan. The description of Cylindrotoma japonica Alexander, 1919, was based on the darker colouration of the thorax (Fig. 3D ) ( Alexander 1919). The rank of this species was first questioned by Paramonov (2006), who referred to it as a subspecies of C. distinctissima in his identification key of The Cylindrotomidae of Far East Russia. Our morphological and genetic comparisons suggest that C. japonica does not differ significantly from C. distinctissima , even at the subspecies level. The colouration of C. japonica shows a high level of variability in Japan. The specimens collected in Hokkaido Island, have, typically, three separated black marks on the mesonotum (Fig. 3C ). Small genital differences occur between the typical examples of C. distinctissima and C. japonica , in the shape of the apical gonocoxal lobe (rectangular in Japanese specimens (Fig. 6D ) and less sclerotised and rounded in studied European specimens Fig. 6E ), the shape of aedeagus (evenly narrowing in Japanese specimens Figure 6L , and broader at the middle in examined European specimens Fig. 6M ), as well as the shape of the gonostylus in caudal view (Fig. 6F, G ). However, these also show variability amongst specimens (see illustrations by Peus 1952: fig. 27; Salmela and Autio 2007; figs 1e, 2b, e). Ujvárosi et al. (2011: fig. 2) illustrated the high variability level of the ventral lobe of the gonocoxite in Bulgarian and Romanian populations in the case of C. d. distinctissima , but we did not find that similar variability in C. japonica specimens examined. C. japonica syn. nov. and C. distinctissima are now synonymised based on the high colour variability level, the minimal genital differences, and the small genetic differentiation between the species.

Four species of Cylindrotoma have been described from the Nearctic, which are related to C. distinctissima , namely C. americana Osten Sacken, 1865, C. juncta Coquillett, 1900, C. splendens Doane, 1900, and C. pallescens Alexander, 1931. After the revision of North American Cylindrotomidae , these later three species were synonymised with C. americana , and the latter species was treated as a subspecies of C. distinctissima as C. distinctissima americana Osten Sacken, 1865, as their male terminalia were highly similar to each other ( Brodo 1967). Molecular analysis shows a relatively high (~ 4.6%) genetic distance between the Nearctic and Palearctic subspecies, and a slight genital difference between these two clades was found in our study (see below the comparative diagnosis of C. americana ). Based upon the two subspecies’ genetic and geographic separation, the two subspecies are now raised to species rank, C. americana stat. reval. and C. distinctissima . Furthermore, the Nearctic C. americana shows an additional molecular differentiation, as specimens from Jasper National Park, Alberta, Canada were found to belong to a separate barcode BIN (BOLD:ABA1601), and the remaining sequences, both from western and eastern parts of North America represent another barcode BIN (BOLD:AAV1805). The phylogenetic relationship between these clades is not resolved in the molecular tree and lowly supported (Bootstrap: 65) in our analysis.

Figures

Figure 3. Cylindrotoma distinctissima (Meigen, 1818) A habitus of male, lateral view (colouration of wings is artefact) B thorax of male, lateral view C head and thorax dorsal view of pale " Cylindrotoma distinctissima " form D head and thorax dorsal view of dark, " Cylindrotoma japonica " form E head of female, lateral view F head of male, lateral view G female terminalia lateral view.

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 6. Male genital structures of Cylindrotoma distinctissima (Meigen, 1818) (A-M), in comparison to C. americana Osten Sacken, 1865 (N-P) A terminalia, dorsal view B terminalia, ventral view C terminalia, lateral view; D Apical lobe of the gonocoxite (Japan) E apical lobe of the gonocoxite (Finland) F shape of the gonostylus caudal view (Japan) G shape of the gonostylus caudal view - Finland H aedeagus complex, dorsal view I aedeagus complex, ventral view J aedeagus complex, lateral view K tip of the aedeagus L shape of the aedeagus (Japan) M shape of the aedeagus (Finland); C. americana Osten Sacken N apical lobe of the gonocoxite O shape of the gonostylus caudal view P shape of the aedeagus. Abbreviations: ae - aedeagus; al - gonocoxite apical lobe; eja - ejaculatory apodeme; gc - gonocoxite; gs - gonostylus; ib - interbase; pm - paramere; sp - sperm pump; s 9 - sternite 9; t 9 - tergite 9; vl - gonocoxite ventral lobe.

Figure 7. Female genital structures of Cylindrotoma distinctissima (Meigen, 1818) (A-J) and C. americana Osten Sacken, 1865 (K) A terminalia, dorsal view B terminalia, lateral view C shape variant of median lobe of tergite 10 (Krasnodar Krai, Russia) D shape variant of median lobe of tergite 10 (Finland) E sternite 8 and hypogynial valves, inner dorsal view F shape variant of tip of the hypogynial valve G sternite 10 H genital opening and sperm ducts I spermathecae (Japan) J spermathecae (Finland) K spermathecae of C. americana Osten Sacken, 1865. Abbreviations: ce - cutting edge; crc - cercus; hv - hypogynial valve; t 8 - tergite 8; t 9 - tergite 9; t 10 - tergite 10; t 10 s - tergite 10 triangular sclerite; t 10 ll - tergite 10 lateral lobe; s 8 - stergite 8.

Figure 8. Occurrence data in Japan and surrounding areas of A Cylindrotoma distinctissima (Meigen, 1818) B Diogma glabrata (Meigen, 1818) and D. caudata Takahashi, 1960. Red dots indicate locations of investigated specimens, white dots indicate approximate locations of literature data. Green dot indicate approximate location of type locality of D. caudata Takahashi, 1960.