Nilodosis austrosinensis, Tang & Cranston, 2017

Tang, Hongqu & Cranston, Peter S., 2017, Review of Nilodosis Kieffer (Diptera: Chironomidae: Chironominae), with description of a new species from South China, Zootaxa 4353 (2), pp. 339-346 : 340-345

Nilodosis austrosinensis sp. n.

urn:lsid:zoobank.org:act:6FAFC229-4060-4106-B76F-44A21CE7678B

Nilodosis sp. 'Guangdong', Tang and Yamamoto 2012: 209.

Material examined. Holotype, ♂, CHINA: Guangdong Province, Guangzhou City, Conghua, Liuxihe Reservoir , 25.x.2014, light trap, leg. Jun Liu.

Paratypes: ♀, Macau SAR, Coloane, Hac-Sa Reservoir, 10.xi.2014, leg. Hongqu Tang ; ♀, as previous except 01.xii.2014; 2♂♂, one as holotype, the other with associated pupal exuviae reared in the lab, Macau SAR, Coloane, Hac-Sa Reservoir, 18.viii.2014, leg. Hongqu Tang (30.viii.2014 emerged) ( ANIC) ; Pe , as holotype, 31.x.2014; 2 Pe, Macau SAR, Coloane, Hac-Sa Reservoir, 21.x.2014, leg. Hongqu Tang .

Other examined material, 2 ♂♂, as holotype, 06.vii.2013, leg. Hongqu Tang . 2♂♂ in alcohol, as previous except 15.x.2009; 2♂♂ in alcohol, as previous except 26.vii.2016, leg. Hongqu Tang, Masaru Yamamoto and Nao Yamamoto; 2 L, as paratypes, one 18.ii.2014, another 21.x.2014; 12 Pe, Guangdong Province, Huazhou City, Hejiang Town , Tangkeng Country , 04.viii.2013, leg. Hongqu Tang ; Pe, as previous except Pingding Town , 11.xi.2013 ; 3 Pe, as previous except Luo River in Huazhou section, 04.viii.2013 ; 3 Pe, as previous, except Changqi Town, Nan’an Country , 05.viii.2013 ; Pe , as previous, except 23.xi.2013.

Description. Adult male (n = 4) total length 3.38–4.15, 3.72 mm (summer population larger, 4.15 mm), and abdomen 2.33–2.87, 2.54 mm. Wing length 1.58–2.00, 1.73 mm (summer average: 2.0 mm, autumn average: 1.6 mm). Ratio total length/wing length 2.06–2.31, 2.18. Ratio wing length/length of profemur 1.88–2.08, 1.97.

Colour. Head and thorax brown to dark brown. Mesonotum with central dark band and 2 lateral dark vittae, central one usually separated into 2 narrow bands by yellowish area bearing acrostichals. Postnotum black. Abdominal tergites dark brown, fainter in intersegmental area, but lacking clear markings. Legs with distinctive pattern ( Fig. 1B ), coxa usually dark brown, trochanter usually yellow, without dark pigment. Profemur usually with proximal 1/2 whitish, mid–femur largely dark brown, hind–femur usually with 2 whitish areas. All tibiae seem alike, each with 2 whitish bands, one located in the proximal 1/6, the other in sub–apical area. Ta1–2 largely pale yellow, with distal joints area dark brown, ta4–5 usually dark brown, without pale area. Ta3 varies between legs, proximal 1/3 pale on proleg, whole brown on midleg, proximal 4/5 pale on hind leg.

Head. AR 1.33–1.49, 1.43. Segment 1–12 450–480, 458 µm long, ultimate flagellomere 600–715, 655 µm long. Temporal setae 10 including 4–5 inner verticals and 4 outer verticals. Clypeus with 16–20, 18 setae. Tentorium 118–130, 122 µm long, 30–40, 35 µm wide. Palpomere lengths (in µm): 40–50, 45; 20–40, 36; 190–200, 195; 130–150, 140; 155–185, 173. Palpomere 4 shorter than 3rd and 5th, 5th/3rd 0.81–0.95, 0.90 ( Fig. 1C ).

Wing ( Fig. 2A ). Wing rather smoky, with some faint punctation under high magnification. VR 0.97–1.01, 0.99; R with 8–14, 10, R1 with 13–18, 15, R4+5 with 20–26, 24 setae. Squama with 2–4, 3 setae.

Thorax ( Fig. 1A ). Dorsocentrals 10–15, 13, acrostichals 8–12, 10, starting at antepronotum, prealars 3–4. Scutellum with 6–10, 8 setae.

Legs ( Fig. 1D–F ). Arcuate curved long tibial spur on the tibiae of all legs, of which fore tibia spur is largest, 50–60, 55 µm long, while mid tibial spur relatively small. Combs on mid and hind tibiae fused, occupying about half circumference. Pulvilli vestigial. Lengths (in µm) and proportions of legs in Table 1.

Male Fe Ti Ta1 Ta2

P1 800–975, 885 430–525, 468 960–965, 963 700–750, 735

P2 680–800, 750 550–700, 632 520–530, 528 220–230, 226

P3 820–1000, 910 610–775, 687 800–820, 810 350–380, 370

Ta3 Ta4 Ta5 LR

P1 450–510, 487 380–430, 415 120–200, 145 2.08–2.15, 2.11

P2 160–170, 165 115–120, 118 80–90, 85 0.86–0.88, 0.87

P3 290–305, 298 170–200, 188 110–120, 117 1.21–1.29, 1.24 Hypopygium ( Fig. 2B ). Tergite VIII not constricted at base. Anal point 30–33, 32 µm long, relatively short, tapered from base, and apically slightly pointed ( Fig. 2C ). Anal tergite bands fused in oval area, with 6–8 median setae in pale area. Phallapodeme 60–65, 63 µm long. Transverse sternapodeme 38–40, 39 µm long, sternapodeme narrow with slight oro-lateral projection. Gonocoxite 95–100, 97 µm long. Superior volsella ( Fig. 2D–G ) bearing elongate, bare, apically hooked digitus, 40–55, 48 µm long, the basal section widest, with expanded setose and microtrichiose pad, usually bearing 3 strong long setae. Inferior volsella 58–63, 60 µm long, bulbous apically, extending slightly beyond the apex of anal point. Gonostylus 100–125, 110 µm long, with 8–10, 9 long setae along inner margin, apex narrow. HR 1.09–1.45, 1.27. HV 2.30–2.38, 2.33.

Adult female (n = 2) Medium–sized with abdomen length 2.45–3.25 mm, wing length 1.72–2.15 mm. Color as in male, with same distinctive leg pattern.

Head. Antenna with 6 flagellomeres, lengths (in µm): 50–60, 55; 55–65, 57.5; 65–70, 68.8; 65–80, 71.5; 62– 70, 65.6; 115–125, 122.5. AR 0.36–0.42, 0.39. Each segment of 1–5 with 2–3 sensilla, pale, distal segment dark brown, with 4–5 pale spots ( Fig. 1G ). Eye bare, with slight dorsomedial extension. Frontal tubercles absent. Inner verticals 2–3, outer verticals 4–6, clypeals 24–27. Palp 5-segmented, lengths (in µm): 45–50, 46.5; 25–35, 30; 180– 245, 211.3; 120–180, 156.3; 210–240, 225; palp 2 rectangular, shorter than wide; palp 3 approximately 6× as long as wide; palp 4 slightly shorter, approximately 5× as long as wide, palp 5 subequal to 3rd.

Thorax. Antepronotal lobes medially divided at notch. Acrostichals 10–14, uniserial, dorsocentrals 8–11, prealars 2–3, supraalars 1, scutellars 5–6.

Wing. Grey, with fine to fair punctuation. Anal lobe reduced, costa not extended. R with 18–27 setae, R1 with 18–30, R2+3 without seta, R4+5 with 36–55. VR around 1.0. Squama with 3–4 setae.

Legs. Similar to males, mensural features in Table 2.

Genitalia ( Fig.2H ). Gonocoxapodeme gently curved, not fused medially. Gonapophysis VIII with only dorsomesal lobe, covered with some small microtrichia, the apex usually curved. Ventrolateral lobe and apodeme lobe absent. Labium with microtrichia. Gonocoxite IX small, with 4–8 setae. Postgenital plate large, with long setae and fine microtrichia. Seminal capsules oval. Cerci somewhat elongated and spindle shaped.

Female Fe Ti Ta1 Ta2

P1 900–1025, 962 510–600, 548 1125–1250, 1188 825–950, 887

P2 790–920, 870 680–790, 750 530–640, 585 210–160, 238

P3 990–1150, 1088 750–870, 815 840–1025, 935 390–500, 450

Ta 3 Ta4 Ta 5 LR

P1 540–675, 608 480–550, 515 220–238, 230 2.08–2.21, 2.15

P2 160–180, 175 110–140, 125 80–110, 95 0.75–0.79, 0.78

P3 310–350, 330 190–225, 208 137–142, 140 1.12–1.18, 1.15 Pupa (n = 4). Exuviae yellow-grey, apophyses brown. Total length 4.63–5.95, 5.15 mm, abdomen length 3.50– 4.80, 3.98 mm.

Cephalic tubercles and frontal setae absent ( Fig. 3A ). Thoracic horn with 6–8 main branches, basal ring pearl– shaped ( Fig. 3B ). Mid–thorax with conspicuously large tubercles at median suture ( Fig. 3C ). Antepronotum with 1 median and 2 lateral setae. 3 fine precorneals; dorsocentrals: dc1 close to dc2, separated clearly from approximated dc3 and dc4, all subequal and fine, 50–60, 55 µm.

Abdomen: Tergite I bare, II–VII with areas of fine spinules, subquadrate on II–V, with paired longitudinal bands on VI and anterior transverse patch on VII. Tergite VIII (seldom with a few anterolateral spinules) and anal segment bare ( Fig. 3D ). Tergite II hook row continuous, 400–550, 463 µm long, 0.68–0.74, 0.72 times as wide as corresponding tergite width, comprising 65–100, 82 small hooks. Conjunctives III/IV and IV/V with narrow row of small anteriorly directed spinules, with complete band in the former, and interrupted in the latter. Sternites IV and V bare, VI–VIII with anterior paired spinule patches, I–III with patches strongly developed and extending posterolaterally ( Fig. 3E ). Vortex present on parasternites IV and V, present only as darkened areas on parasternites VI–VII; pedes spurii B rounded, protruding on segment II. Posterolateral corner of segment VIII with strong multispined mace ( Fig. 3F ). Anal lobe ratio 1.93–2.14, 2.05.

Setation.Segment I with 2 D, 1 V and with 1 L setae; II–VII with 4–5 D, 2– 3 V; 3 L on II–IV, V–VII with 4 lateral taeniae, VIII with 0 D, 2 V, 5 lateral taeniae, two V setae rather stoutly taeniate.

Anal lobe rather elongate, with fringe of 45–82, 62 taeniae, biserial over anterior 1/5, mainly uniserial in middle 2/5 and becoming more crowded to biserial in posterior 1/5. Without dorsal taeniate seta. Genital sac of male extending beyond apex of anal lobes, female genital sac shorter than the anal lobe and with a fused hyaline “cercus” extending clearly from the anal lobe.

Larva. As described by Tang & Yamamoto (2012) under the name Nilodosis sp. 'Guangdong'.

Etymology. From Latin, meaning southern China, referring to the type locality.

Figures

FIGURE 1. Nilodosis austrosinensis sp. n., A–F male, G female. A. thorax; B. leg (from left to right, fore, middle and hind); C. maxillary palp; D–F.details of tibial spur and comb (from left to right, fore,middle and hind); G. female antenna.

FIGURE 3. Nilodosis austrosinensis sp. n., pupa. A. frontal apodome; B. thoracic horn; C. thorax (lateral view); D. abdomen I–IX, dorsal view; E. abdomen I–VIII, ventral view; F.posterolateral comb of segment VIII.

FIGURE2. Nilodosis austrosinensis sp. n., A–G male, H female.A. wing; B. male hypopygium; C. details of anal point; D–G. superior volsella; H. female genitalia.