Conchapelopia brachiata, Niitsuma, Hiromi & Tang, Hongqu, 2017

Niitsuma, Hiromi & Tang, Hongqu, 2017, Notes on the genus Conchapelopia Fittkau (Diptera: Chironomidae: Tanypodinae) from southern China, with description of a new species, Zootaxa 4236 (2), pp. 327-334 : 328-332

Conchapelopia brachiata sp. n.

( Figures 1; 2A, C, E; 3A–E)

Type material. Holotype, male with pupal and larval exuviae, CHINA: Guangdong Province, Guangzhou City, Huangpu District, Bage county , a brook near Jinyuan Villa , 23°13'54.90''N, 113°26'19.59''E, alt. 122m, 2.iii.2016, (emerged 6.iii.2016), HQ Tang . Paratypes: 1 male, as holotype except 19.xii.2015, light trap; 1 male, CHINA: Guangdong Province, Guangzhou City, Conghua District, Lyutian Town , a brook in Mt. Guifeng , 27.ii.2015, HQ Tang ; 1 male with pupal exuviae, as previous except 20.iv.2015 (emerged 26.iv.2015); 1 male, Guangzhou City, Conghua District, Lyutian Town , Dongkeng stream, 9.ix.2015, light trap, HQ Tang ; 1 male, Fujiang Province, Wuyishan National Nature Conservation Reserve, Changjian country, 13.xi.2012, sweep, HQ Tang ; 1 male, Anhui Province, Huangshan Nature Conservation Reserve, Tangkou Town, Fu stream in Mt. Huang , 30°04.317'N, 118°09.320'E, alt. 520 m, 27.v.2012, light trap, HQ Tang ; 1 male with pupal exuviae, as previous except 4.v.2014.

Etymology. From Latin brachiatus (brachiate), referring to the arm-like basolateral appendage of the median volsella in the male hypopygium.

Diagnosis. The male adult of the new species is distinguished from others by the combination of the following characters: median volsella with an arm-like basolateral appendage and 6–8 lamellate processes in the apical half; wing with three distinct crossbands. The pupa and larva cannot be separated from those of C. togamaculosa clearly.

Description. Male (n = 8). Total length 3.7–4.1, 4.0 mm. Wing length 2.0–2.5, 2.2 mm. Total length/wing length 1.68–1.95, 1.81.

Coloration: Body yellow with brown markings ( Fig. 1 A). Head with brown clypeus. Thorax dark brown on anepisternum II, preepisterum and postnotum. Scutum with 2 pairs of dark spots on median vittae, and 1 pair of dark spots on lateral vittae. Abdominal tergites II–VI each with anterior dark brown band in apical 2/5, but bands on T II and occasionally T VI interrupted in middle; T VII–VIII almost entirely dark brown. Hypopygium pale yellow. Wing with 3 distinct transverse brown bands. Legs pale yellow, with slightly brown ring at subapices of femora.

Head: AR 1.71–2.02, 1.84. Terminal flagellomere 80–100, 89 µm long. Temporals 14–18, 16, consisting of 3– 4, 3 inner verticals, 10–12, 11 outer verticals, and 2–3, 2 postorbitals. Clypeus with 22–26, 24 setae. Lengths of palpomeres 1–5 (in µm): 50–80, 56; 80–100, 89; 140–200, 179; 180–210, 195; 280–345, 320.

Thorax: Antepronotals 4–6, 5; acrostichals 36–50, 43, biserial anteriorly; dorsocentrals 20–32, 26, generally uniserial; prealars 14–18, 16, fairly uniserial; supraalar 1. Scutal tubercle 30–45, 38µm wide, 10–15, 13 µm high. Scutellum with 24–30, 27 setae.

Wing: VR 0.90–0.95, 0.92. Squama with 24–36, 28 setae.

Legs: All legs with long tibial spurs each bearing 6–8 lateral teeth. Front tibia with one spur 33–35, 34 µm long. Spurs of middle tibia 45–50, 48 and 50–55, 52 µm long, respectively; length ratio of inner spur to outer spur 1.0–1.1, 1.1; tarsomere 3 with distinct brush of 20–24 strong setae. Spurs of hind tibia 40–45, 42 and 70–80, 77 µm long, respectively; length ratio of inner spur to outer spur 1.8–2.0, 1.9; tibial comb consisting of 6–8, 7 bristles. Lengths and proportions of legs as in Table 1 .

Hypopygium ( Fig. 1 B): T IX with 12–15, 14 setae on each lateral tubercle. Gonocoxite 140–160, 148 µm long, with 3–5, 3 strong preapical setae. Median volsella ( Fig. 1 C) 75–108, 99 µm long, with arm-like basolateral appendage curved downward, bearing 6–8 slender blades on apical 2/3; with 6–8, 6 scalpel-shaped lamellate processes on apical 0.43–0.54, 0.46, sometimes 1–2 apical processes simple; pubescent ventral lobe absent.

Pupa (n = 3). Body length 3.5–3.8, 3.7 mm. Total length 4.8–5.0, 4.9 mm.

Coloration: Exuviae largely pale brown; apophyses of abdominal tergites III–VI darkened at middle.

Cephalothorax: Thorax without distinct granulation, only with some wrinkles along anterior half of median suture. Thoracic horn ( Fig. 2 A) 275–300, 286 µm long, 3.67–5.00, 4.54 as long as broad, and slightly swollen apically; external membrane with scattered weak spines. Corona 120–140, 131 µm long, occupying apical 0.44– 0.48, 0.46 of thoracic horn. Plastron plate oval, 40–50, 44 µm long in major axis, 0.14–0.18, 0.15 times as long as horn length, 0.29–0.38, 0.33 times as long as length of corona, with 8–12, 10 ostia on apical surface. Atrium somewhat amoeboid in coronal area, but simple in basal 3/5. Thoracic comb consisting of 30–60 apically rounded tubercles, arranged in 4–6 rows; largest tubercle at most twice as long as its diameter. Elliptical dark patch present on median suture ( Fig. 2 E).

Abdomen: Spinulation mainly composed of single and bifid, occasionally multifidi, strong spinules on T I– VIII, of simple and weak spinules on T IX. T I–VII each with more or less extensive spinulation; T VIII medially with pair of kidney-shaped spinulation patches ( Fig. 2 C); T IX with anterior spinulation. Segments I–VI each with 2 pairs of flattened L-setae; VII with 1 pair of flattened L-setae and 4 pairs of LS-setae; VIII with 5 pairs of LSsetae. Anal lobe 395–420, 403 µm long, 2.35–2.44, 2.40 times as long as broad, with 9–12 spines along outer margin, and 5–8 spines along inner margin; male genital sac 0.62–0.65, 0.64 times as long as lobe.

Fourth instar larva (n = 1). Body length ca. 4 mm.

Coloration: Body pale yellow when live. Apical part of ligula and tips of mandibles brown to dark brown.

Head: Length 740 µm, cephalic index 0.72. Cephalic seta S5 slightly anteromedial to grouped S7 and S8; sensory pore DP almost same size as setal socket of S8, and posterolateral to S5. VP and setal sockets of S9 and SSm subequal in size, distinctly larger than setal socket of S10 ( Fig. 3 D, E). Lengths of antennal segments I–IV (in µm): 225, 53, 8, and 5, respectively ( Fig. 3 B); AR 3.46. Antennal segment I 11.25 times as long as basal width, with ring organ located 0.68 from base; blade 65 µm long, reaching base of segment IV, with basal ring 0.16 times as long total length; accessory blade slightly longer than blade; style almost as long as segment III. Mandible 130 µm long. Basal segment of maxillary palp ( Fig. 3 C) 45 µm long, 4.50 times as long as basal width, with ring organ located 0.72 from base; B-seta with 3 sections in proportion of 3:4:2. M-appendage with 6 rows of granules on pseudoradula 6 µm wide at middle. Ligula ( Fig. 3 A) 75 µm long, 1.76 times as long as toothed width; paraligula 38 µm long, forked at middle. Pecten hypopharyngis with 20 teeth on each side.

Body: Procercus 100 µm high, 4.0 times as long as wide, bearing 7 anal setae 580 µm long. Supraanal seta 520 µm long.

Distribution. China (Anhui, Fujian and Guangdong Provinces).

Female. Unknown.

Remarks. The male of the new species is similar to that of C. togamaculosa Sasa & Okazawa in the threecrossbanded wing, but distinct in the hypopygial median volsella with an arm-like basolateral appendage. In C. togamaculosa , the basolateral appendage is a short conical projection (see Niitsuma 2008: 97, fig. 38). The immature forms of both the species much resemble each other. Especially these pupae are exactly alike as the thorax has an elliptical dark field on the scutal median suture, and a relatively small plastron plate and an apically amoeboid atrium in the horn, and each of the abdominal segments I–VI is armed with 2 pairs of flattened L-setae. The pupa and larva unassociated with their adult male cannot be identified with confidence. For the same reason the description of the adult female cannot be given.

The long basolateral appendage and the banded wing may separate the new species from other congeners except African species C. cygnus (Kieffer) and Oriental species C. insolens Murray. In the latter two species, however, the wing has two bands, and the basolateral appendage of median volsella is armed with lamellae along its entire length (see Freeman 1955: 24, fig. 6a; Murray 1995: 418, fig. 1), whereas in the new species, the wing has three crossbands, and the basolateral appendage of median volsella possesses lamellae or broadened setae only on apical two-thirds.

A

A

C D D A

E F B C

Tables

TABLE 1. Lengths (µm) and proportions of legs of Conchapelopia brachiata sp. n., male (n = 8).

	fe	ti	ta1	ta2	ta3	ta4	ta5
P1	925–1075 996	1175–1400 1279	1050–1110 1070	520–570 543	370–400 380	270–280 273	130–140 137
P2	975–1150 1047	1000–1050 1078	560–620 594	270–380 308	220–260 234	180–210 196	100–110 104
P3	900–1100 975	1250–1525 1366	980–1000 990	520–535 526	380–400 390	260–270 268	130–135 133