Dactylolabis (Dactylolabis) longicauda Alexander, 1922

Kato, Daichi, 2023, Taxonomic study of the genus Dactylolabis Osten Sacken, 1860 of Japan (Diptera: Limoniidae), Zootaxa 5375 (2), pp. 227-240 : 234-239

Dactylolabis (Dactylolabis) longicauda Alexander, 1922

( Figs 4 , 5 , 6B )

Dactylolabis longicauda Alexander 1922: 184 . Type locality: Japan, Honshu, Ôsaka, Mt. Minomo .

Dactylolabis flavidipennis Alexander 1922: 184 . Type locality: Japan, Honshu , Gifu.

Dactylolabis longicauda : Alexander 1930: 507; Alexander 1953: 81; Alexander 1954: 293.

Dactylolabis longicauda megastylata Alexander 1930: 521 , syn. nov. Type locality: Japan, Nansei Islands , Yaku-shima Island, Kosugidani.

Dactylolabis (Dactylolabis) longicauda : Nakamura 2014: 9; Kato & Yamauchi 2023: 5 ; Oosterbroek 2023.

Dactylolabis (Dactylolabis) longicauda megastylata : Nakamura 2014: 9.

Type material examined. HOLOTYPE, male, JAPAN, Nansei Islands, Kagoshima, Yakushima, Kosugidani , altitude 2,500 feet, N30.34°, E130.55°, 29.IV.1929, S. Issiki (as Dactylolabis longicauda megastylata Alexander, 1930 ) ( USNM) . PARATYPES: JAPAN: [Honshu] 1 male, Ôsaka, Mount Minomo , N34.85°, E135.46°, 4. V .1921, K. Takeuchi (as D. longicauda longicauda Alexander, 1922 ) ( USNM); 1 male, same data as holotype of D. l. megastylata (as D. l. megastylata). Other examined material . JAPAN: [Honshu] 1 male, Aomori, Nishimeya-mura, Kawaratai, Ôkawa-rindô Path , altitude 300 m, N40.5006°, E140.2040°, 30. V .2014, D. Kato ( BLKU) ; 1 male, Niigata, Tokamachi-shi, Matsunoyama, Echigo-Matsunoyama Museum of Natural Science , ‘ Kyororo’ , altitude 310 m, N37.0995°, E138.6163°, 9. V .2020, D. Kato ( BLKU) ; 1 male, Niigata, Itoigawa-shi, Kajiyama, near Amakazari Spa , altitude 861 m, N36.9213°, E137.9539°, 14. VI .2022, D. Kato ( BLKU) ; 1 male, 1 female, Toyama, Toyamashi, Arimine, Inone-dani Valley , altitude 1134 m, N36.4905°, E137.4656°, 15. VI .2022, D. Kato ( BLKU) ; 1 male, Gifu, Sakauchi , N35.59°, E136.42°, 4. V .1958, Mishima ( USNM) ; 1 male, 1 female, Aichi, Seto-shi, Katakusachô , altitude 400 m, N35.26°, E137.16°, 5. V .2012, D. Kato ( BLKU) ; 4 males, Aichi, Toyota-shi, Kawashimo-chô, tributary of Yahagi-gawa River , altitude 140 m, N35.2037°, E137.3012°, 4. V .2014, D. Kato ( BLKU) ; 2 males, Yamanashi, Kôshu-shi, Enzankamihagihara , altitude 1360 m, N35.7092°, E138.8274°, 7.VII.2014, D. Kato ( BLKU) ; 1 female, Mie, Matsuzaka-shi, Iitaka-chô-Kuwabara, Tsukide-gawa River , altitude 320 m, N34.425°, E136.163°, 15.IV.2014, D. Kato ( BLKU) ; 4 males, 1 female, Mie, Matsuzaka-shi, Okawachi-chô , altitude 73 m, N34.5197°, E136.4727°, 15. V .2014, D. Kato ( BLKU) ; 1 male, Yamaguchi, Iwakuni-shi, Nishiki-machi-Ôno, Mt. Shôjô-yama , altitude 330 m, N34.2999°, E131.9375°, 2. V .2016, D. Kato ( BLKU). [Shikoku] 1 male, Iyo (Ehime), Omogokei , altitude 800 m, N33.72°, E133.09°, 10. V .1952, Ishihara ( USNM) ; 1 male, 1 female, Iyo (Ehime), Mt. Ishizuchi , 9. VI .1950, Issiki-Ito ( USNM) ; 1 male, same data as previous except 8. VI .1950; 1 male, 1 female, Kagawa, Mannô-chô, Katsuura , altitude 480 m, N34.0940°, E134.0143°, 16. V .2015, D. Kato ( BLKU) ; 1 male, Awa (Tokushima), Mt. Tsurugi , 1400–1955 m, N33.85°, E134.09°, 1. VI .1950, Issiki-Ito ( USNM) ; 2 males, 1 female, Tokushima, Higashimiyoshi-chô, Nishisyô, Kamodani-gawa River , altitude 170 m, N34.0153°, E133.9432°, 21.IV.2014, D. Kato ( BLKU) ; 1 male, Tokushima, Miyoshi-shi, Higashiiya-Oshima, Oshimadani-gawa River , altitude 550 m, N33.8870°, E133.8716°, 29.IV.2016, D. Kato ( BLKU) ; 1 male, Ehime, Kumakôgen-chô, Hinoura, near Prefectural road 328, altitude 1490 m, N33.5703°, E132.9381°, 17. VI .2019, D. Kato ( BLKU) ; 1 female, Ehime, Shikokuchuôshi, Sangawa-chô, Hase-gawa River , altitude 260 m, N33.9487°, E133.5055°, 20.IV.2014, D. Kato ( BLKU) ; 1 male, 2 females, Ehime, Mima-shi, Waki-machi, Shimizu , Soedani-gawa River , N34.15°, E134.15°, 5. V .2016, M. Aoyagi ( BLKU) ; 6 males, 2 females, Ehime, Saijô-shi, Nishinokawa-Tei, Mt. Ishizuchi-san , altitude 1530 m, N33.7547°, E133.1530°, 16. VI .2019, D. Kato ( BLKU) ; 8 males, 2 females, Ehime, Tôon-shi, Kamihayashi , altitude 400 m, N33.741°, E132.891°, 20.IV.2014, D. Kato ( BLKU). [Kyushu] 1 male, Fukuoka, Kitakyushu-shi, Kokuraminami-ku, Dôbaru , Takinoguchi-gawa River , N33.790°, E130.817°, 17.IV.2019, R . Toda ( BLKU) ; 1 female, Fukuoka, Fukuoka-shi, Nishi-ku, Myôbaru , Myôbaru-gawa River , altitude 160 m, N33.5618°, E130.2638°, 26.III.2016, D. Kato ( BLKU) ; 1 male, same data as previous except 15.IV.2016 ; 1 female, Fukuoka, Fukuoka-shi, Nishi-ku, Kuwabara , Biodiversity Conservation Zone of Kyushu Univ. , altitude 38 m, N33.5980°, E130.2161°, 15.IV.2016, T . Mishima ( BLKU) ; 1 male, 1 female, Fukuoka, Miyako-machi, Saigawa-Hobashira, Notôge Pass , altitude 740 m, N33.4956°, E130.9615°, 22.IV.2016, D. Kato ( BLKU) ; 3 males, Saga, Saga-shi, Fuji-machi-Sekiya, Kase-gawa River near Hokuzan Dam , altitude 320 m, N33.4332°, E130.2321°, 12.IV.2015, D. Kato ( BLKU) ; 2 males, same data as previous except 23.IV.2015 ; 2 males, 1 female, Saga, Karatsu-shi, Kyuragi-machi-Hirano, Mt. Sakurei-zan , altitude 860 m, N33.3570°, E130.0703°, 26.IV.2015, D. Kato ( BLKU) ; 1 female, Saga, Karatsu-shi, Hamatamamachi-Torisu, Tsubakiyama Pond , altitude 630 m, N33.4041°, E130.1064°, 26.IV.2015, D. Kato ( BLKU) ; 1 male, Kumamoto, Yatsushiro-shi, Izumi-machi-Momiki , altitude 1350 m, N32.4812°, E131.0123°, 11. V .2016, D. Kato ( BLKU) ; 1 male, Kumamoto, Yatsushiro-shi, Futamisuguchimachi , altitude 7 m, N32.4106°, E130.5388°, 10.IV.2019, R . Toda ( BLKU) ; 2 males, 1 female, Kirishima , altitude 2500 feet, 3. V .1929, S. Issiki ( USNM). [Nansei Islands] Yakushima Island : 1 male, 1 female, Onoaida, Ara-kawa River , altitude 1200 m, N30.299°, E130.556°, 4–7. VI .2007, CT, Yamauchi et al. ( BLKU) ; 1 male, 1 female, same data as previous except 7–28. VI .2007, MT .

Redescription. Male. Body length 6.0– 9.8 mm, wing length 6.2–9.0 mm.

Head. Grey, sparsely clothed with brown and yellow setae. Anterior part of vertex with narrowest part slightly wider than eye in dorsal view; vertex posterior to eye as long as eye. Antenna generally yellowish brown to brownish black, about 2.5 times length of head. Scape greyish by pruinosity, 3–4 times as long as wide. Pedicel often brownish, twice longer than wide and half as long as scape, distal part distinctly broader. Flagellomere oval, twice as long as wide on flagellomere 1, gradually decreased in size toward apical segment; each segment with about four verticils, at most as long as corresponding segment, and covered with pale pubescence, about 1/4 length of corresponding segment; pubescence on terminal flagellomere indistinct. Rostrum grey, 3/4 as long as scape. Palpus dark brown to black; palpomere 1 small, roundish; palpomeres 2–5 almost same in length, each segment three times as long as palpomere 1; palpomere 4 slightly broader than other segments. Labellum dark brown to black.

Thorax. Generally grey, notum sparsely covered with short yellow setae. Pronotum sometimes bearing brown longitudinal line at middle of antepronotum; postpronotum sometimes yellowish or brownish laterally.Prescutum and presutural scutum often widely tinged with ocherous on center, with four brown stripes, more evident in anterodorsal view; middle pair distinct, running from anterior end of mesonotum to slightly before transverse suture, often fused at posterior end; lateral pair broader and shorter, about half length of middle one, reaching to transverse suture and joining dark marking on scutal lobes; scutal lobe with large brown area at middle, sometimes vaguely separated by narrow greyish line near middle; in paler colored specimens, dark markings on mesonotum weakened. Mediotergite weakly dark on posterior half in dorsal view. Pleuron grey, dorsopleural membrane brighter or yellowish. Wing ( Fig. 4C ) tinged with yellow to brown, prearcular region indistinctly yellow in darker specimens. Stigma sometimes vaguely darker. Rs weakly curved near base; cell dm 2–2.5 times as long as wide. Legs covered with short black setae. Coxae and trochanters yellow to ocherous, coxae dusted with grey in various degrees, sometimes entirely grey. Remainders of legs yellow to dark brown; in darker specimens, femora to tarsi generally dark brown, basal 1/3 of femora gradually turning into yellow toward bases; in lighter colored specimens, femora to tarsi generally yellowish, tips of tibiae and distal parts of tarsi darkened. Halter yellow to dusky yellow, sometimes whitish.

Abdomen. Dusky yellow to dark brown, often paler on sternites, sparsely covered with yellowish short setae; setae on hypopygium longer and darker.

Hypopygium ( Figs 4D–J ) with epandrium ( Fig. 4D ) roughly trapezoid in dorsal view, wider distally, longer than wide. Hypandrium ( Fig. 4E ) strongly and widely convex posteriorly at middle of posterior margin. Proctiger ( Fig. 4D ) roughly squarish, lateral lobe ( Fig. 4F ) slender tongue-shaped, narrower on distal 1/3, twice as long as wide. Gonocoxite ( Fig. 4G ) 2.5–2.7 times as long as wide, and about 1.2 times longer than epandrium, slender and curved, basal part weakly wide. Outer gonostylus ( Fig. 4H ) stout and bacilliform, 0.6–0.8 times as long as gonocoxite, slightly longer to shorter and much wider than inner gonostylus; inner gonostylus ( Fig. 4H ) slender and strongly curved at middle, tip rounded. Interbase ( Figs 4I–J ) with middle part fused and forming narrow band, bearing pair of claw-shaped ventral lobes, gradually narrow to tip and slightly arched; posterior margin of interbase without notch at middle; lateral arm wider on distal part, curved medially. Paramere ( Figs 4I–J ) slender, weakly curved outward. Aedeagus ( Figs 4I–J ) cylindrical, relatively slender, almost straight and bent posteroventrally on distal 1/3, tip ending at level of posterior end of interbase. Sperm pump ( Figs 4I–J ) small, 0.4 times as long as and about three times as wide as aedeagus. Ejaculatory apodeme ( Figs 4I–J ) with each arm narrow, directing anteriorly.

Female. Body length 6.2–8.4 mm, wing length 7.2–8.3 mm. Generally resembling male.

Female terminalia ( Figs 5A–F ). Brown to yellow. Cercus ( Fig. 5B ) yellow, slightly shorter than tergite 10, weakly constricted near middle of dorsal margin, basal part covered with long hair-like setae ventrally, distal part with very short setae; ventral margin at distal 1/6 strongly curved; distal 1/6 gradually narrowed to tip; posterodorsal edge produced posteriorly into small lobe. Sternite 8 ( Fig. 5D ) squarish, slightly longer than wide in ventral view. Hypogynial valve wide blade-shaped, about twice as long as sternite 8, gradually narrowed to tip in ventral view; tip ending near level of middle of cercus. Sternite 9 ( Fig. 5C ) narrow, nearly rectangular, about 1/4 times as long as wide, with posteriorly directed slender arm at posterolateral corner. Genital frame ( Figs 5E–F ) with genital fork slender rod-shaped, curved in dorsoventral axis, about twice as long as remainder of genital frame, anterior part directed anterodorsally; lateral arm long oval, central part weakly produced; common spermathecal duct long, if bent anteriorly, furcation point situated at middle of genital fork.

Distribution. Japan (Honshu, Shikoku, Kyushu, and Nansei Islands (Yakushima Island)) ( Fig. 6B ) and?Russian Far East (Sakhalin) ( Oosterbroek 2023).

Remarks. The specimens collected in Yakushima Island were treated as the different subspecies, Dactylolabis longicauda megastylata Alexander, 1930 , based on the larger outer gonostylus than that of D. l. longicauda Alexander, 1922 . However, by examining additional specimens from various sites in Japan, including the site near the type locality of D. l. megastylata, the size of the outer gonostylus of the specimens in Yakushima Island has a variation and it falls within that of the specimens from the other localities in Japan. Therefore D. l. megastylata is synonymized with the nominotypical subspecies in this paper.

This species resembles a Chinese species, D. (D.) gracilistylus Alexander, 1926 , but is differentiated from it by the following characters: halter yellowish to whitish (dark brown in at least knob in D. gracilistylus ); lateral arm of interbase slender, basal part distinctly narrower than distal part ( Fig. 4I ) (stout, almost same width in whole length in D. gracilistylus ); aedeagus ending at level of posterior margin of middle of interbase ( Figs 4I–J ) (extending beyond posterior margin of middle of interbase in D. gracilistylus ); ejaculatory apodeme almost straight and directed anteriorly to anterolaterally ( Fig. 4I ); (curved and directed laterally in D. gracilistylus ).

Figures

FIGURE 4. Dactylolabis (Dactylolabis) longicauda Alexander, 1922. A. habitus with darker coloration, lateral view; B. same with lighter coloration; C. wing; D. hypopygium, dorsal view; E. male hypandrium, ventral view; F. lateral lobe of proctiger, outer view; G. gonocoxite, outer surface; H. gonostyli, dorsal surface. I. aedeagal complex, dorsal view. J. same, lateral view (left side directing dorsally). Scale bars: A–B, 3 mm; D–J, 0.1 mm.

FIGURE 5. Ovipositor of Dactylolabis (Dactylolabis) longicauda Alexander, 1922. A. ovipositor, lateral view; B. cercus, lateral view; C. sternite 9 ventral view (upper side directing posteriorly); D. sternite 8 and hypogynial valve, ventral view; E. genital frame, dorsal view (upper side directing posteriorly); G. same, lateral surface (left side directing dorsally). Scale bars: A–G, 0.1 mm.

FIGURE 6. Distributions of Japanese species of Dactylolabis. A. D. (D.) diluta (red circle) and D. (D.) kyororo sp. nov. (green square); B. D. (D.) longicauda.