Diogma caudata Takahashi, 1960

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

Diogma caudata Takahashi, 1960

Figs 4B , 5C , 8B , 11 , 12 , 13

Diogma caudata in Takahashi 1960: 82-84: original description; Siitonen 1984: 203: faunistic record; Sidorenko 1999: 68-70: identification key, illustration, distribution; Oosterbroek et al. 2001: 122: distribution; Paramonov 2004a: 258: faunistic record; Paramonov 2005: 211: comparison; Mukkala et al. 2005: 7: faunistic record; Bartsch et al. 2005: red list status, faunistic record; Paramonov 2006: 888-889: identification key, illustration, distribution; Polevoi 2006: 96: faunistic records; Sandström 2008: red list status; Salmela 2008: 12: ecology; Salmela 2012a: 242: distribution; Salmela 2012b: 16: distribution; Salmela and Petrašiūnas 2014: 31: checklist; Nakamura 2014: 54: distribution.

Type material examined.

Diogma caudata Takahashi: Holotype: • ♂; Japan, Hokkaido, Mount Meakandake; 5 Jul. 1958; M. Takahashi leg.; ELUK.

Non-type material examined.

Finland • 3 ♂, 1 ♀; Kaavi, Kalalamminpuro; 63.11458°N, 28.67255°E; alt. 140 m; 20 Jun. 2008 - 17 Jul. 2008; J. Salmela leg.; LMM, CKLP. Russia • 1 ♂, 1 ♀; Arkhangelsk Oblast, Plesetsk District, Obozersky Settlement, around the settlement; 63.44231°N, 40.30789°E; alt. 100 m; 26 Jun. 1959; N.P. Krivosheina leg.; CKLP. • 1 ♂; Karelia Republic, Kon: 6909:550, Kondopoga District, Kivach Nature Reserve, spruce forest; 62.26766°N, 33.97975°E, alt. 42 m; 19 May. 1993 - 23 Jun. 1993; A.V. Polevoi leg.; window trap; ZIN. • 1 ♂; Karelia Republic, Karelia, Kon: 6982:570, Medvezhyegorsk Urban Settlement, 3 km NW Medvezhyegorsk City, point № 6; 62.93364°N, 34.38467°E; alt. 130 m; 19 Jul. 2002; A.V. Polevoi leg.; ZIN. • 1 ♂; Perm Krai, Kungur Urban Okrug, Kungur City, forest station; 57.42881°N, 56.944206°E; alt. 219 m; 16 Jun. 1960; K.B. Borisova leg.; ZIN. • 1 ♂; Tuva Republic, Tandinsky District, north slope of Tannu-Ola mountains, near Chagytaj Lake; 50.99591°N, 94.6764°E; alt. 1500 m; 24 Jun. 1963; N.A. Violovich leg.; ZIN. Sweden • 2 ♂; Lule Lappmark, Kaltbacken bei Messaure; 66.67347°N, 20.32239°E; alt. 240 m; 23 Jun. 1969 - 26 Jun. 1969; • 1 ♀; same locality; 22 Jun. 1970 - 24 Jun. 1970; • 2 ♂; same locality; 23 Jun. 1971 - 30 Jun. 1971; • 31 ♂, 4 ♀; same locality; 12 Jun. 1972 - 13 Jul. 1972 / 21. Aug. 1972 - 28 Aug. 1972; • 2 ♂; same locality; 19 Jun. 1973 - 25 Jun. 1973; • 1 ♂, 1 ♀; same locality; 17 Jun. 1974 - 8 Jul. 1974; K. Müller leg.; ZFMK.

Redescription.

Head. Dorsally dark brown, ventrally brown. Frons with white pubescence noticeable only in dry specimens (Fig. 11C, D ). Rostrum pale brown, short, without nasus, with few hairs. Mouthparts pale brown to brown (Fig. 11C, D ). Palpus pale brown to brown, short, five segmented; last segment slightly longer than penultimate segment (Fig. 11B ). Scape cylindrical, 2 × as long as pedicel; pedicel ovate, slightly darker than scape; flagellum 14-segmented, gradually darkening from base to tip; segments simple in both sexes, not expanded ventrally (Figs 4B , 11E, F ); in male, first flagellomere as long as wide, remaining segments cylindrical; last segment 1.2-1.3 × as long as penultimate segment; flagellomeres with short, relative sparse whitish setae (sensilla), just slightly denser in ventral and lateral sides (Fig. 11E ); in female, last flagellomere 1.8-2 × as long as penultimate; last 4-6 segments without sensilla (Figs 4B , 10F ). Verticels black, shorter than length of flagellomere; usually one verticel in ventral surface and two or three in dorsal/dorsolateral sides, first segment with 4-6 verticels.

Thorax. General colouration yellowish brown with contrasting, shiny black markings. Mesonotum pale brown, greenish yellow in fresh, living specimen ( Takahashi 1960), with three separated, broad, longitudinal black markings (Fig. 11C ); several small yellow setae along pale strips. Scutellum yellow. Posterior part of mediotergite black. Anepisternum and katepisternum separated, both ventral parts dark brown to black. Ventral corner of laterotergite black. Additional small darker patch on posterior basalare, and on ventral part of meron. Coxa and trochanter yellowish, darker on anterior- dorsal parts (Fig. 11B ); femur pale brown; tibia gradually darkening from pale brown to dark brown/black; tarsus uniformly black. Wing hyaline; veins pale brown to brown; pterostigma pale (Fig. 5B ); three branches of M reaching wing margin; M1 in same level as M1+2; cell a2 narrow,> 7 × longer than wide (Fig. 5B ); membrane with interference patterns, visible with dark background (Fig. 11A ). Halter monochrome, yellow or pale brown.

Abdomen. Tergites and sternites pale brown to brown, tergite 8 and sternite 8 darker than others (Fig. 11A ). Pleural parts greenish in living specimen ( Takahashi 1960).

Male terminalia: Black, large, complex, directed caudally. Tergite 9 not fused with gonocoxite, partly cover gonocoxite (Fig. 12C ); medial part rounded with small tuft of hairs (Fig. 12A ); lateral lobe of tergite 9 greatly extended, complex; as long as basal part of tergite 9; ventral portion of lateral lobe elongated, finger-like in lateral view (Fig. 12C ); lateral margin almost straight or weakly divergent in dorsal view (Fig. 12A, B ); ventral base of lateral lobe with small, black, heavily sclerotised lobe (Fig. 12C, E ) - named lamina by some authors - shape variable; posterior margin of tergite 9 between median round part and lateral lobe covered with dense short, blunt ended setae (Fig. 12A ). Gonocoxite complex; apical lobe with dense hairs (Fig. 12B-D ); ventral lobe round, almost bare (Fig. 12B, D ); inner part of gonocoxite with basally directed lobe, with hairs on margin (Fig. 12D ). Gonostylus simple, wider at middle (Fig. 12F ); with finger-like membranous lobe on inner side, poorly visible in dry specimens (Fig. 12G ). Aedeagus bifid; aedeagus with apical branches long, curved ventrally almost in right angle, then curved in right angle posteriorly, then turn dorsally in right angle in lateral view (Fig. 12J ); dorsal lobe between interbases complex, sclerotised (Fig. 12H, J ); interbase with ventral projection (Fig. 12J ). Sperm pump and ejaculatory apodeme small (Fig. 12H-J ), covered by parameres in lateral view (Fig. 12J ).

Female terminalia: Brown, tip of cercus and hypopygial valve yellowish brown. Tergite 8 separated at middle by membranous area (Fig. 13A ). Tergites 8 and 9 similar in size (Fig. 13B ). Ventral corner of tergite 9 rugged (Fig. 13B ). Triangular sclerite separated from tip of tergite 10 (Fig. 13A ). Lateral lobes of tergite 10 elongated, with few longer hairs (Fig. 13A, B ). Cercus and hypogynial valve simple, wide, blade-shaped, tips rounded (Fig. 13B ). Dorsal apical surface of cercus rough, formed by few blunt, pyramid or round teeth (Fig. 13A, B ). Base of sternite 8, weakly sclerotised, extended laterally at middle, with transverse creases (Fig. 13AC). Two round spermathecae present, duct curved (Fig. 13D ). Lateral sclerite of genital fork elongated; two sperm ducts simple, without any clear markings (Fig. 13D ).

Distribution.

Finland, Japan (Hokkaido I, Fig. 8B ), Sweden, and Russia (Kareliya Republic, Perm Krai and Tuva) ( Oosterbroek 2021). First records from Arkhangelsk Oblast, Russia.

Comments.

The species was initially described from Hokkaido, Japan. However, no additional Japanese data has been published, and the species was not found in the type locality in our study. The species later was reported from Finland, Sweden, and Russia (Karelia Republic, Perm Krai, and Tuva). Morphologically it is a well separated species from the close related Diogma glabrata , but the Finnish specimens show only a small COI genetic difference from it and form a clade together with the West Palearctic D. glabrata . No significant morphological differences were found between the Finnish and Russian specimens and the Japanese holotype.

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 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.

Figure 10. Female genital structures of Cylindrotoma nigriventris Loew, 1849 A terminalia, lateral view B sperm ducts C Spermathecae.

Figure 11. Diogma caudata Takahashi, 1960 A habitus of the holotype male, lateral view (colouration of wings is artefact) B head and thorax of female, lateral view C head and thorax of female, lateral and dorsal views D head of female, dorsal view E antenna of holotype male F antenna of female.

Figure 12. Male genital structures of Diogma caudata Takahashi, 1960 A terminalia, dorsal view B terminalia, ventral view (aedeagus complex removed) C terminalia, lateral view D gonocoxite, inner lateral view E shape of heavily sclerotised lobe (lamina) of tergite 9 F shape of the gonostylus, caudal view G shape of the gonostylus, inner ventral view H aedeagus complex, dorsal view I aedeagus complex, ventral view J aedeagus complex, lateral view. Abbreviations: ae - aedeagus; al - gonocoxite apical lobe; eja - ejaculatory apodeme; gsl - lobe of gonostylus; ib - interbase; ibml - interbase median lobe; ibvl - interbase ventral lobe; pm - paramere; sp - sperm pump; t 9 l - tergite 9 lateral lobe; vl - gonocoxite ventral lobe.

Figure 13. Female genital structures of Diogma caudata Takahashi, 1960 A terminalia, dorsal view B terminalia, lateral view C sternite 8, hypogynial valve, genital fork, and sperm ducts, inner dorsal view D spermathecae. Abbreviations: 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.