Tanypus nakazatoi, Kobayashi, Tadashi, 2010

Kobayashi, Tadashi, 2010, A systematic review of the genus Tan yp u s Meigen from Japan, with a description of T. n ak aza toi sp. nov. (Diptera: Chironomidae: Tanypodinae), Zootaxa 2644, pp. 25-46 : 26-34

Tanypus nakazatoi sp. nov.

Figures 1, 2 , 5–7 , 10–12 , 14, 15 , 19–24 .

Tanypus punctipennis Meigen, 1818 : Sasa & Kawai 1987, p. 60 plate 20 a–j.

Tanypus sp. TA Kitagawa 1980: pp.24–25 Fig. 6 ; 1986, pp.25–26 Fig. 14 ; 1994, p.19 (photo); 1997, p.71 Fig. 43.

Material examined. Types of T. nakazatoi are deposited in the National Museum of Nature and Science, Tokyo ( NSM). Specimen code (NSMT-I-Dip No.) in parentheses. Sasa collection is also deposited at NSM. Some larvae are mounted on the same slides.

Type material. Holotype. Adult male, JAPAN: Ibaraki, Ibaraki University, Center for Water Environmental Studies ( CWES), located near Lake Kita-Ura, 35°59’52’’N, 140°33’34’’E, 22.vii.2009, light trap, Nakazato R (6582). Paratypes. Adult males: 3, as holotype except for 12.vi.2003, (6583–85); 10, as holotype except for 5.vi.2001 (6586–95); 2 as holotype except for 25.vii.2006, (6596, 97); 20, as holotype (6598–6617); 2, as holotype except for 3.viii.2008, (6618, 19). 1, Lake Biwa, Ohtsu, Shiga, 49. ix.1985, sweeping net, Kobayashi T (Sasa collection-Tanypodinae 29:75); 1, Lake Biwa, Shiga, 19.ix.1985, light trap, Sasa M (Sasa collection 108:85). Adult females: 3, as holotype except for 5.vi.2001, (6620–22); 3, as holotype except for 12.vi.2003, (6623–25); 4, as holotype except for 22.vii.2009, (6626–29); 1, as holotype except for -. viii.2008, (6630). Pupa: 1, Ibaraki, Lake Kitaura, 3.viii.2008, rearing, Nakazato, R (6681). Pupal exuviae: 1, as previous (6682). Larvae: 7, Ibaraki, Lake Kitaura, 18.iv.2001, Ekman-Birge dredge, Nakazato R (6631–37); 4, as previous except for 21.ix.2001 (6638–41); 2, as previous except for 16.v.2001, (6642, 43); 6, as previous except for 9.iii.2009 (6644); 10, as previous except for 8.viii.2008 (6645, 6646, 6673–80); 10, as previous except for 3.iii.2009 (6647–49); 5, as previous except for 7.iii.2009 (6650); 17, as previous except for 2.iii.2009 (6651–54); 49, as previous except for 3.iii.2009 (6655–64); 50, as previous except for 5.iii.2009 (6665–72); 1, Chiba, Lake Teganuma, 9.iii.2009, dredge, R. Kuranishi leg. (Sasa collection-Tanypodinae 29:98); 1, Chiba, Lake Imbanuma, -.-.1997, Ekman-Birge dredge, Kitagawa N (Kitagawa collection); 1, Nagano, Lake Suwa, 30.xi.2005, Ekman-Birge dredge, Nakazato R (Nakazato collection); 5, as previous except for 20.iv.2007; 3, as previous except for 18.vi.2008 (Nakazato collection).

Comparative material examined T. grandis (deposited at University of Burdwan) Paratype. Female: 1, India, Burdwan, 3.iv.1978, Pal S. Pupal exuviae: 1, India, Burdwan, --. xi.1980, Nandi SK. Larva: 1, as previous. T. punctipennis (deposited at Zoologische Staatssammlung München) Larva: 1, Germany, Bavaria, 14.viii.1978, Kohmann F.; 1, Westphalia, --. vi.1912.

Description. Adult male (n = 40). Total length 4.2–6.5, 5.47mm (38). Wing length 2780–3890, 3190μm (34).

Coloration. Head with eye brown, palpomeres pale brown, pedicel brown, antennal shaft and plumose pale brown, thorax brown with darker vittae, ScuT paler, scutellum pale brown, abdominal tergite brownish darker medially.

Head ( Fig. 5 ). Eye with parallel-sided dorsomedian extension. Temporals 16–25, 20.4 (10), clypeals 10– 18, 14.0 (10). Antenna with 14 flagellomeres. Ultimate flagellomere offset basally, with apical setae 20–37, 30.5μm (10) long ( Fig. 6 ), length of antenna 1580–1845, 1688μm (26). AR 2.49–3.06, 2.75 (26). Pedicel with 4–5, 4.6 (5) ventral setae, scape bare. Groove beginning at 3rd flagellomere. Tentorium 200–275, 244μm (7) long, 55–80, 72.9μm (7) wide. Palp consisted of 5 palpomeres, first palpomere often indistinct, lengths of palpomeres in Table 1.

1 2 3 4 5

Male 25–50 35.9 (11) 40–60 49.5 (28) 80–120 101.3 (28) 125–160 146.1 (27) 200–260 225.4 (26) Female – 50–60 56.3 (4) 100–110 107.5 (4) 160–185 168.8 (4) 240–290 257.5 (4) Thorax. Antepronotum well developed with 14–25, 18.8 (10) ventrolateral setae. Large (150–250, 181μm (10) long, 70–110, 87μm (10) wide), oval ScuT present bearing slightly recurved bristles about 30μm long, that easily fall off. Dc uniserial 19–30, 23.6 (17) including humerals. Ac biserial or multiserial from ScuT to lateral vittae diverging in turned V-shaped, absent in front of ScuT. Medial scar present. Pa 10–15, 11.9 (10) uniserial, Su 1–2, 1.5 (11). Scts 7–16, 10.9 (10) in transverse row, and a group of 0–5, 1.8 (10) anterior fine setae.

Wing ( Fig. 1 ). Costa produced, reaching apex of wing. Stalk (or petiole) 120–270, 180.5μm (37) long. VR 0.85–1.08, 1.02 (37). RM and MCu darkened. CuR about 0.25. Wing membrane with 4 conspicuous dark spots on cell r4+5; cell r1+2 with 3–4, cell r3+4 with 0–3 paler spots, and cell an with some indistinct clouds. Length of spot 3 ( Figs. 1 , 30) 120–300, 197μm (35), spot 4 100–300, 165μm (35), distance between spots 3–4 130–260, 197μm (35), ratio distance spots 3–4/wing length 0.044–0.087, 0.064 (34). VR 0.85–1.08, 1.02 (37). Wing membrane with setae on apical part. Squamals 29–52, 40.0 (5).

Legs. Leg measurements and proportions as in Table 3. Femur of all legs with subapical, and tibia with subbasal and apical dark bands, ta1–ta3 with apical dark band, ta4 and ta5 almost dark. Spur of foretibia 68–90, 77μm long (10), with one tooth; outer spur of midtibia 35–65, 53μm long (9), with 2–3, 2.5 teeth (4); inner spur of midtibia 52–70, 60μm long (9), with 2–3, 2.8 teeth (4); outer spur of hind tibia 45–80, 59μm long (10), with 2–3, 2.5 teeth (4); inner spur of hind tibia 80–120, 89μm long (10), with 3 teeth (1), tibial comb with 6– 10, 7.4 stout setae (19). Sensilla chaetica on ta1 of mid leg 6–13, 8.3 (21) in number (Fig. 32). Claws apically palmate, with strong 5–6 ventro-basal spines, empodium as long as half the length of claw. Pulvilli absent.

Hypopygium ( Figs 7 , 31). Tergite IX with 20–30, 24.5 short setae (10) posteriorly. Gonocoxite 270–340, 298μm long (35), bearing many dorsomedian robust setae. Gonostylus 175–230, 186μm long (35), 4–6 innerbasal setae, and with 8–12 dorsomesal setae; HR 1.44–1.71, 1.61 (36), HV 0.30–0.43, 0.34 (35), carina present, phallapodeme distinct, 100–160, 127μm long (14); transverse sternapodeme arched anteriorly.

Adult female (n = 11). Total length 3.2–5.7, 4.23mm (11). Wing length 2630–4100, 3356μm (7).

Coloration. As in male.

Head ( Fig. 10 ). Eye dorsomedian extension weak ( Fig. 10 ). Temporals 14–24, 20.0 (5), clypeals 16–26, 20.8 (5). Antenna ( Fig. 11 ) with 14 flagellomeres, antennal length 900–1030, 964μm (5), ultimate flagellomere 200–250, 222μm (5), AR 0.27–0.33, 0.30 (5). Pedicel with 10–13, 116 (5) ventral setae, scape with 4–6, 5.0 (5) ventral setae. Lengths of palpomeres 2–5 in Table 1. First palpomere often indistinct.

Thorax. Antepronotum well developed with 11–26, 21.0 (5) ventrolateral setae (antepronotals). Large (250–280, 265μm (2) long, 70–80, 75μm (2) wide), oval ScuT present. Dc uniserial 30–38, 33.6 (17) including humerals. Ac biserial or multiserial between vittae from ScuT diverging in turned V-shaped posteriorly, absent in front of ScuT. Medial scar present. Pa 12–18, 14.2 (5) uniserial. Su 1 (5). Scts 11–16, 13.9 (7) in transverse row, with a group of 1–11, 4.7 (6) anterior fine setae.

Wing ( Fig. 2 ). Wing markings as in male. All specimens examined with 4 spots on cell4+5. Length of spot 3 ( Figs. 2 , 30) 170–250, 201.9μm (11), of spot 4 105–280, 198.5μm (10), distance between spots 3–4 130–290, 221.8μm (11), ratio distance spots 3–4 by wing length 0.052–0.084, 0.066 (7). VR 1.00–1.03, 1.01 (3). RM and MCu darkened. Wing membrane with setae in apical part. Squamals 36–86, 59.4 (5).

Legs. Coloration as in male. Leg measurements and proportions as in Table 3. Spur of foretibia 58–75, 69μm long (6), with 2–3, 2.2 teeth (6); outer spur of midtibia 48–60, 55μm long (4), with 2 teeth (2); inner spur of midtibia 55–68, 60μm long (4); outer spur of hind tibia 55–75, 63μm long (5); inner spur of hind tibia 70–110, 90μm long (5), tibial comb with 7–8, 7.3 stout setae (6). Number of SCh on ta1 of mid leg 31 (2), much larger than in male. Pulvilli absent, claws apically palmate.

Genitalia ( Fig. 12 ). Seminal capsules not reticulated by 2 sets of lines perpendicular to each other (cf. Saether 1977), 110–140, 118μm long (4), 70–90, 80μm wide (4), spermathecal ducts not observed in any of the examined specimens. Gonocoxapodeme VIII normal. Gonapophyses IX somewhat semicircular. Notum 400– 420, 404μm long (5). Tergite IX completely fused with gonocoxite IX to form a bare gonotergite IX. Coxosternapodeme simple and straight. Segment X covered with microtrichia. Postgenital plate reduced.

Pupa (n = 2). Thoracic horn ( Fig. 15 ) globose, asymmetrically biconvex, 920μm (1) long, 535μm (1) wide, external membrane densely covered by spines, thin-walled filling the entire lumen and with a narrow apical neck surrounded by an apical papilla; plastron absent. Thoracic comb with about 10 weak tubercles. Segment I without LS seta, II with 6, 6 (right, left) III with 20, 17, IV with 24, 28, V with 38, 38, VI with 50, 53 and VII with 35, 31 LS setae; VIII with 5 taeniae and anal lobe with 2 long taeniae (NSMT-I-Dip 6682) ( Fig. 14 ).

Larva (4th instar) (n = 171). Body length 10–12mm, brownish yellow, index capitis ca. 1 ( Fig. 19, 20 ). Tentorial line thin and short ( Fig. 20 ), triangular pigmentation spot between the tentorial lines indistinct or absent (cf. Vallenduuk and M. Pillot 2007). Antenna slightly curved outward, outer margin of first segment 155–175, 165μm (6), inner margin 210–225, 216μm (6), RO situated near the tip of outer margin, 1/20th of outer margin from the base. AR 5.25–6.14, 5.52 (6) ( Fig. 21 ). Mandible ca. 120μm long, with enlarge base and very small accessory teeth ( Fig. 22 ). Ligula ( Fig. 23 ) narrow, with 5 teeth, apices of all teeth towards straight; teeth-row concave slightly anteriorly, 112–140, 123.1μm (71) long, 34–48, 39.9μm (69) wide at base, 14–27, 18.9μm (67) at minimum width. Length of Li divided by basal width 2.5–3.6, 3.1 (64). Paraligula ( Fig. 23 ) very characteristic, comb-like with 32–42, 36.7 fine branches (39). Dm ( Fig. 23 ) with 6–8, 7.0 tooth on each side (25), tooth-line straight or slightly concave posteriorly. Fulcrum with numerous fine long hairs ( Fig. 23 ). Body segments with fringe of setae, setae on prothorax ca. 90, on metathorax ca. 70 (on each side). Anal tubules 6, pointed apically ( Fig. 24 ). Collecting sites of T. nakazatoi in Fig. 33 .

Etymology. The species is named in honour of Dr. Ryoji Nakazato (Ibaraki University) for providing with many specimens collected from his study area.

Diagnostic characters of Tanypus nakazatoi . T. nakazatoi is similar to T. punctipennis as adult and pupa. However ligula and paraligula of larvae differ distinctly. Ligula of the former species is slender and long and of the latter one is broad and short. Paraligula in T. nakazatoi is composed of ca. 32 fine, long filamentous on each side ( Fig. 23 ), while it has 11–13 branches (teeth) in T. punctipennis ( Fittkau and Roback 1983, Vallenduuk and Pillot 2007, Makarchenko 2006) ( Fig. 25 ). Ligula and paraligula of the two larval specimens of T. punctipennis from Germany (ZSM) were measured by the author: length of ligula 70, 72, basal width 35, 38, minimum width 25, 20, and ratio of length to basal width 2.00, 1.89 respectively; paraligula with 11 branches on each side, dorsomentum with 8, 9 teeth on each side respectively. Pupal segments II–VIII of T. nakazatoi with a lateral fringe of setae or taeniae are similar to those found in T. punctipennis ( Fig. 14 , Table 7 ). Comparative data on adult males of T. nakazatoi and T. punctipennis by Roback (1977: 74) are shown in Table 6. Gonocoxite and gonostylus of T. nakazatoi are larger when compared with those of T. punctipennis , however HR ratios are almost equal. Concerning male wing spots, T. nakazatoi is keyed to T. punctipennis according to Langton and Pinder (2007).

T. nakazatoi is also similar to T. chinensis in all stages [described from the Oriental region of China ( Wang S 1994, 1997)], except for LR3 of male adult, number of lateral setae on pupal segments, and number of paraligula filamentous (teeth, branches) ( Table 7 ). LR3 of the adult male of T. chinensis is lower than in T. nakazatoi . In pupae, number of lateral fringe setae of T. chinensis is much lower than in T. nakazatoi . Paraligula of T. nakazatoi bears 32–42, 36.6 (44) filamentous, whereas in T. chinensis it has 21–26 filamentous (Wang S, ibid.), which data show clear differences between the species compared. Comparative data is summarized in Table 7 . Unfortunately, the types of T. chinensis have been lost (Wang X., pers. comm.).

T. nakazatoi is also close to T. grandis . Its immature stages were described by Das and Chaudhuri (1989). Holotype of T. grandis could not be had a loan, but the paratypes of female, pupal exuviae and larva could be examined. Larva of T. grandis having paraligula with 32–33 filamentous resembles T. nakazatoi . However, these two species differ each other in some points as follows.

Adult male. Distance between Spot 3 and Spot 4 in cell r4+5 is 48μm in T. grandis (measurement based on Fig. 2 . Chaudhuri et al. 1988), while it is 130–260, 197μm (35) in T. nakazatoi . LR 2 in male of T. grandis is much smaller than in T. nakazatoi : 0.84 and 0.88–1.01, 0.94 (16), respectively. Carina of gonostylus is ‘distinct membranous’ in T. grandis , while it is weakly developed in T. nakazatoi .

Adult female. Distance between wing Spot 3 and Spot 4 in cell r4+5 is 60μm in T. grandis (measurement based on the paratype), while it is 130–290, 222μm (11) in T. nakazatoi .

Pupa. Thoracic horn of T. grandis is much smaller than that one in T. nakazatoi , i.e. 553μm (measurement based on Fig. 2 d, Das and Chaudhuri 1989) and 920μm long respectively. Number of abdominal lateral setae on segments I–VII in T. grandis is much lower than in T. nakazatoi , i.e. 2, 3, 12, 21, 28, 33, 25, and 0, 6, 17– 20, 24–28, 38, 50–53, 31–35 respectively.

Larva. Ligula in T. grandis is smaller than that one of T. nakazatoi , i.e. 70–90, 80μm long (10) and 112– 140, 123μm long (71) respectively. Comparative data are summarized in Table 7 .

The number of comb-like paraligula filamentous seems to be variable in some close species, i.e. 10 in T. concavus ( Fittkau and Roback 1983, Fig. 5.30D), 11 in T. punctipennnis (Fittkau and Roback ibid.: Fig.

5.31.B), 13 ( Vallenduuk and Pillot 2007, Fig. 88; Sergeeva 1995: 70, Fig. 4 ), 21–26 in T. chinensis , and 32–42 in T. nakazatoi and T. grandis . It may be likely that the more number of paraligula, the narrower ligula.

Figures

FIGURES 1 – 4. Wings. Scale 1000 μm. 1. Tanypus nakazatoi sp. nov., male; 2. T. nakazatoi sp. nov., female; 3. T. kraatzi (Kieffer), male; 4. T. kraatzi (Kieffer), female.

FIGURES 5 – 7. Tanypus nakazatoi sp. nov. adult male. Scale 5, 500 μm; 6, 100 μm; 7, 200 μm. 5. Head, 6. Tip of antenna, 7. Hypopygium.

FIGURES 10 – 12. Tanypus nakazatoi sp. nov. adult female. Scale 10 – 12, 500 μm. 10. Head, 11. Antenna, 12. Genitalia. FIGURE 13. Tanypus kraatzi (Kieffer), adult female. Scale 500 μm. Genitalia.

FIGURES 14 – 15. Tanypus nakazatoi sp. nov. pupa. Scale 14 – 15, 500 μm. 14. Abdomen, 15. Thoracic horn. FIGURES 16 – 18. Tanypus kraatzi (Kieffer), pupa. Scale 16, 500 μm; 17, 1000 μm; 18, 100 μm. 16. Thoracic horn, 17. Abdominal segments V – VIII, 18. Posterolateral corner of segment VIII and anal lobe.

FIGURES 19 – 24. Tanypus nakazatoi sp. nov. larva. Scale 19, 20, 500 μm; 21 – 24, 100 μm. 19. Head dorsally, 20. Head ventrally, 21. Antenna, 22. Mandible and maxillary palp, 23. Ligula and paraligula, MApp (M appendage), Dm (dorsomentum), Fu (fulcrum), 24. Anal part.

FIGURES 33 – 34. Collecting sites of Tanypus nakazatoi sp. nov. (33) and Tanypus kraatzi (Kieffer) (34).

FIGURES 25 – 29. Tanypus kraatzi (Kieffer), larva. Scale 25, 27, 28, 50 μm; 26, 100 μm; 29, 200 μm. 25. Ligula and paraligula, 26. Antenna, 27. Dorsomentum and M appendage, 28. Mandible, 29. Anal part.