Chaudhuriomyia binduensis, Paul, Nilotpol & Mazumdar, Abhijit, 2015

Paul, Nilotpol & Mazumdar, Abhijit, 2015, Chaudhuriomyia, a new tanypod genus of Macropelopiini (Diptera: Chironomidae: Tanypodinae) from the Eastern Himalaya, Zootaxa 3955 (4), pp. 537-548 : 542-543

Chaudhuriomyia binduensis sp. n.

Type material. Holotype: Adult male (Type no. B.U. Ent. 250) with larva and pupa (reared), Bhutan, Bindu, Jaldhaka Barrage (27º 06.15ʹN and 88º 52.15ʹE), 02.IV.2012, coll. N. Paul. Paratypes: 1 male and 3 female with larvae and pupae (reared), data same as above; 1 male with larva and pupa (reared), India, West Bengal, Jhalong (27º 02.27ʹN and 88º 53.37ʹE), 08.IV.2012, coll. N. Paul.

Etymology. The new species is named after the type locality.

Diagnosis. Male Adult (n = 2; except when otherwise stated) ( Figs. 1–10 )

Total length 3.75–3.79 mm; wing length 1.95–1.98 mm (n = 3); total length/wing length 1.91–1.92; wing length/profemur length 1.91–1.98.

Head ( Fig. 1 ): Eyes with 97–109 Μm dorsomedial extension. AR 1.98–2.23; pedicel pale with 6–7 setae; apical seta, 0.80 × length of terminal segment; length (Μm) of flagellomeres (I–XIV): 45–52, 22–26, 24–29, 24–29, 24– 29, 24–29, 24–29, 24–29, 24–29, 24–29, 24–29, 24–29, 598–630, 89–97. Temporal setae 23–25 on each side (9–11 IV, 12–14 OV, 0 Po). Clypeus with 27–29 setae. Length (Μm) of palpomeres (I–V): 56–62, 45–52, 120–127, 207– 214, 255–270. CA 0.48–0.52; CP 0.73–0.76.

Thorax ( Fig. 2 ) (n = 3): Acrostichals 28–30 biserial between the vittae; Scutellum with 19–21 setae; dorsocentrals 34–35 irregularly placed. Antepronotal lobe with 9–12 setae. Prealarls 14–16. Postnotals 6–8.

Wing ( Fig. 3 ): VR 0.84–0.85. Costal extension 95–112 Μm long, well beyond M1+2. Brachiolum with 2 setae and 7 scf; squama with 27–28 setae, 105–195 Μm long; wing moderately setose, macrotrichia scattered in patches,

Leg ( Figs. 4–8 ): Spur of fore tibia ( Fig. 4 ) 57–59 Μm long bearing 12 lateral teeth, spurs of mid tibia ( Fig. 5 ) 61–63 Μm and 48–49 Μm long bearing 13 and 12 lateral teeth, spurs of hind tibia ( Fig. 6 ) 76–79 Μm and 41–42 Μm long bearing 11 lateral teeth each; hind tibia with a tibial comb consisting of 10 bristles. Surface of tibial spurs smooth ( Fig. 7 ). Claw sharp and pointed in mid and hind legs, fore leg claw ( Fig. 8 ) blunt somewhat spatulate shaped, empodium 27 Μm long with 17–20 setae. Segment lengths and proportions of leg as in Table 2 .

Abdomen ( Fig. 9 ): Most tergites possess distinct areas of bands with variable pattern and all tergite moderately setose.

Hypopygium ( Fig. 10 ): Tergite IX with 33–36 setae. Anal point broad, blunt, 136–142 Μm long and 99–107 Μm wide. Gonocoxite 198–212 Μm long with dense strong short 27–28 inner-directed dorsomedian setae. Gonostylus 90–94 Μm long and 26–27 Μm wide with 15–17 Μm long macroseta. Phallapodeme 30–34 Μm long, Sternapodeme 133–147 Μm long, Coxapopodeme 45–53 Μm long. HR 2.01–2.04, HV 4.09–4.11.

Female Adult (n = 3) ( Fig. 11 )

Similar to male with usual sex differences: Coloration as in male but more brownish, AR 0.16–0.19; wing length 2.48–2.54 mm.

Genitalia ( Fig. 11 ): Notum 190–210 Μm long, ramus 60–63 Μm long, vaginal opening more or less ‘Ω’ shaped, cercus 45–60 Μm long; coxasternapodeme IX 120–124 Μm long, gonapophysis VII with 7–11 Μm long setae, seminal capsules 67–79 Μm in diameter, not properly sclerotized.

Pupa (n = 4) ( Figs. 12–22 )

Total length of exuviae 5.12–5.17 mm.

Cephalothorax ( Figs. 12–13 ): Pale brown in color. Frontal apotome 150–227 Μm long, 255–280 Μm wide; frontal setae 252–280 Μm long, precorneal setae 107–119 Μm long; antennal sheath 1050–1103 Μm long. Both Dc1 and Dc2 equally 75–79 Μm long, simple, without granulated. Sa simple and 80–84 Μm long. Thoracic horn ( Figs. 12–13 ) 335–405 Μm long, ThR 1.82–1.85. Plastron plates 105–120 Μm long, occupying 0.50–0.57 of the horn sac with a definite aeropyle. Outer margin of horn sac formed heart shaped with concave distally.

Abdomen ( Figs. 14–22 ): Deep brown in color ( Figs. 14–16 ) except segment I. Scar on tergite I 90 –107 Μm long, elongated, occupying 0.30–0.33 length of the segment, two anterior muscle marks closely present with scar. Segment I ( Fig. 17 ): D1 49–52 Μm long, D 2 23–27 Μm long, D3 34–37 Μm long, D 4 27–28 Μm long, D 5 27–29 Μm long, DL 75–79 Μm long, VL 75–80 Μm long. Segment II: D1 128–135 Μm long, D2 60–67 Μm long, D3 45–52 Μm long, D4 45–47 Μm long, D5 52–55 Μm long, DL 25–32 Μm long, VL 30–40 Μm long. Shagreen solitary in segments I and II. Segment III: D1 135–138 Μm long, D2 75–82 Μm long, D3 90–100 Μm long and strongly hooked, D4 45–47 Μm long, D5 105–108 Μm long, DL 57–64 Μm long, VL 49–52 Μm long; Segment IV ( Figs. 18–19 ): D1 92–120 Μm long, D2 45–52 Μm long, D3 125–150 Μm long and strongly hooked, D 4 30–37 Μm long, D5 45–48 Μm long, DL 40– 47 Μm long, VL 60–62 Μm long. Segment V: D1 145–148 Μm long, D2 130–135 Μm long, D3 170–190 Μm very long and hook, D 4 30–37 Μm long, D5 60–63 Μm long, DL 60–62 Μm long, VL 32–37 Μm long. Shagreen randomly arranged in groups of three to four in segments III–V ( Fig. 20 ). Segment VI: D1 160–168 Μm long, D 2 30–32 Μm long, D3 45–50 Μm long and not hook, D 4 30–32 Μm long, D5 37–39 Μm long, DL 70–74 Μm long, VL 40–44 Μm long. Segment VII: D1 170–178 Μm long, D2 105–110 Μm long, D3 120–126 Μm long and hook, D 4 30–36 Μm long, D5 37–39 Μm long, L 75–80 Μm long and 5 LS setae ( Fig. 21 ) placed 0.57–0.67, 0.71–0.75, 0.78–0.80, 0.84–0.85 and 0.85–0.92 of segment length. Shagreen reduced and solitary in segments VI–VII. Segment VIII: Shagreen absent, D setae absent and 5 LS setae placed 0.34–0.39, 0.45–0.53, 0.56–0.64, 0.69–0.75 and 0.82–0.85 of segment length.

Anal lobe ( Figs. 21–22 ): 650–945 Μm long and rounded with 12–14 inner spinules and 4–5 setae, 2.52–2.62 × as long as segment VIII; anal lobe end with a blunt tooth tubercle ( Fig. 22 ), anal lobe 1.75–1.80 × as long as broad. Anal macrosetae 345–352 Μm long and 375–382 Μm long placed 0.78–0.84 and 0.79–0.85 from lobe length respectively. Male genital sac ending 447–571 Μm short of apex of anal lobe, female genital sac ending 689–710 Μm short of apex of anal lobe.

Larva (n = 3, except when otherwise stated) ( Figs. 23–32 )

Head capsule brown, body yellowish with eight white bands, one on each segment (segments II–VIII).

Total length 6.02–6.22 mm. Head capsule 620–650 Μm long and 495–502 Μm wide, cephalic index 0.77–0.79.

Antenna ( Fig. 23 ): AR 6.0–6.5; length (Μm) of antennal segments (I–IV): 159–164, 8–10, 7–9, 8.5–9; style 6– 8 Μm long, blade 26–29 Μm long, accessory blade 25–27 Μm long; segment IV fragile and somewhat bristle like, ring organ 11–12 Μm long, ring organ exactly in middle of distal 1/3 segment.

Mandible ( Fig. 24 ): 136–141 Μm long; apical tooth 70–74 Μm long, seta subdentalis 11–13 Μm long, basal tooth apprised; ventrolateral seta 1 simple, 40–41 Μm long, seta 2 with two branches 38–42 Μm long, and seta 3 branched and short 5–7 Μm long.

Maxilla ( Fig. 25 ): Basal segment of palp 47–49 Μm long, ring organ placed middle in maxilla, a–seta 15–17 Μm and b–seta 13–14 Μm long.

Mentum and M appendages ( Fig. 26 ): Dorsomentum with bifid inner lobe, 2 small inner and 3 large outer teeth on each side; one minute, indistinct tooth pressed basally on both sides. Pseudoradula 98–103 Μm long, granules formed a stripe shape in middle, stretches proximal to distal.

Ligula and Paraligula ( Fig. 27 ): Ligula 87–91 Μm long, middle tooth 17–19 Μm long, inner tooth slightly bent inward, outer tooth 26–28 Μm long; outer tooth not bent. Paraligula bifid, 38–45 Μm long, inner point 15–16 Μm long and outer point 30–34 Μm long.

Pecten hypopharyngis ( Fig. 28 ): 18–21 teeth, middle teeth larger.

Cephalic setation ( Figs. 29–30 ): Ventrally S9 and S10 closely placed with 203–212 Μm long and 175–183 Μm long simple setae respectively, SSm trifurcate; S9, S10 and SSm forming nearly a right angle orientation and VP placed more postero-lateral from S10. Dorsally S7, S8 and DP almost in straight line, S7 slightly laterally placed. S7 pore larger one with 71–79 Μm long seta and S 8 23 –27 Μm long seta.

Body ( Figs. 31–32 ): Anal tubules 135–150 Μm long, 37–45 Μm wide; subbasal setae 51–54 Μm long; procercus 150–152 Μm long, 30–32 Μm wide with 230–247 Μm long 9 anal setae on each. Supraanal setae 41–42 Μm long; posterior proleg with 13 claws ( Fig. 31–32 ), curvature increase gradually from larger to smallest one, largest claw with 3 inner spines.

Ecology and biology. The 3rd and 4th instar larvae were collected from the slow flowing stream that fall into River Jaldhaka, near Jaldhaka Barrage, Bhutan and another stream from Jhalong, West Bengal in Indo-Bhutan border. The place is characteristic with elevated steep watersheds with eroding rock. The habitat revealed a dense semi deciduous forest with various tropical, sub temperate trees. Larvae occurred on submerged rocky substrate of stream associated with thin litter and algal bloom. The species seems epilithic, embenthic and rheobiontic in nature. The stream water had a temperature of 19ºC (18.89ºC–20.11ºC). The mean pH value was 6.92 (6.81–7.10) and mean conductivity was 314µScm -1 (308–322 µScm -1). Total dissolved substance 223ppm (221–224ppm), salinity 152ppm (149–153ppm) and DO 8mgL -1 (7.8–8.2mgL -1). The mean relative humidity was 52% (50–58%) when these larvae collected from wild. The larvae were reared in laboratory with 19ºC±0.5ºC temperature and pH 7.0 within environmental test chamber. The larvae exhibited the slow, rhythmic and undulating movement of body facing the head upwards while attaching their posterior parapods with substrates. This type of activity lasted for hours and may be attributed to gather food particle. The duration of 4th instar was 7–9 days and it was based on the growth of basal antennal segment and mandible. The pupal duration recorded to be 56–68 hours. The eclosion occurred at late evening. The imagines survive 3 to 5 days.

Figures

FIGURES 1 – 9. Chaudhuriomyia binduensis gen. n. sp. n., adult male. 1. temporal setae; 2. thorax; 3. wing; 4. apex of fore tibia; 5. apex of mid tibia; 6. apex of hind tibia; 7. tibial spurs of legs; 8. claws of fore leg; 9. abdominal tergites.

FIGURES 10 – 11. Chaudhuriomyia binduensis gen. n. sp. n., adult. 10. male hypopygium, left: dorsal and right: ventral view; 11. ventral view of female genitalia.

FIGURES 12 – 22. Chaudhuriomyia binduensis gen. n. sp. n., pupa. 12. thoracic horn; 13. thoracic horn; 14. whole abdomen; 15. first four segments of abdomen; 16. last three segments of abdomen with anal lobe; 17. segment I; 18. segment IV; 19. segment IV; 20. shagreen on tergites II – V; 21. tergites VII – IX (left side); 22. apex of anal lobe.

FIGURES 23 – 32. Chaudhuriomyia binduensis gen. n. sp. n., larva. 23. apex of antenna; 24. mandible; 25. maxilla; 26. mentum & M appendages; 27. ligula & paraligula; 28. pecten hypopharyngis; 29. head capsule with position of cephalic setae & sensory pore – left ventral aspect & right dorsal aspect; 30. cephalic setae & sensory pore (ventral); 31. claws of posterior parapods; 32. claws of posterior parapods.