Orthocladius (Euorthocladius) piloculatus, Kobayashi, Tadashi, 2012

Kobayashi, Tadashi, 2012, A new distinctive species of the genus Orthocladius with hairy eyes from Japan (Diptera: Chironomidae), Zootaxa 3230, pp. 52-58 : 53-56

Orthocladius (Euorthocladius) piloculatus sp. nov.

Type material. Holotype male, JAPAN: Kanagawa, Ashigarakami County, Yamakita-machi, mountain stream, 35?28ʹ1ʺE, 139?3ʹ47ʺN; 580m alt., 16.xii.2010, light trap, Ishiwata S. leg. (NSMT-I-Dip 6791). Paratypes. 15 adult males, as holotype (NSMT-I-Dip 6786–6790, 6792–6801). All material is deposited at the Branch of the National Museum of Nature and Science, Tsukuba, Ibaraki, Japan.

Etymology. From Latin, pilus – hair, – oculus eye, referring to the hairy eyes.

Diagnostic characters. Eye with hairs between ommmatidia longer than height of ommatids ( Fig. 1 D). Acrostichals absent ( Fig. 2 B). Anal point robust, tapering toward apex, rounded apically, with several lateral setae and a few basal setae, without microtrichia except for basal part, crista dorsalis well developed ( Fig. 3 A). Superior volsella low and indistinct, dorsal part of inferior volsella rounded without microtrichia, ventral part broad and low, covered microtrichia with several setae. Virga present consisting of 3–6 spines ( Fig. 3 B).

Description. Male (n=16). Total length 2400–3100, 2744μm (16). Wing length 1900–2390, 2141μm (16).

Coloration: Antenna including plume brown, pedicel darker; head and eye brown; thorax dark brown with darker vittae; legs all light brown, tibial tips darker; abdomen and hypopygium uniformly light brown.

Antenna: 13 flagellomeres, total length of antenna 766–1012, 887μm (16), groove beginning at 3rd flagellomere; flagellomere 2nd–5th with distinct sensilla chaetica ( Fig. 1 B), AR 0.81–1.10, 0.99 (16), apex slightly swollen with a few sensilla chaetica, without strong setae ( Fig. 1 A).

Head: Eye without dorsomedial extension ( Fig. 1 C), with hairs clearly longer than height of ommatidial lenses ( Fig. 1 D), temporals 8–15, 11.6 (11) in number. Tentorium 150–180, 162μm long (12), 30–60, 47.5μm wide (12) at basal 1/2; lengths of palpomeres as in Table 1.

20–30 25.0 (11) 40–50 49.3 (14) 100–120 111.0 (15) 95–120 104.7 (15) 145–175 161.3 (15) Thorax: Antepronotal lobes jointed medially ( Fig. 2 A), lateral antepronotals 2–9, 5 (14); dorsocentrals long (c. 100μm long) and erect, uniserial, 8–16, 12.3 (16) in number, arising from clear pale pits (c. 30μm diameter); acrostichals absent ( Fig. 2 B), prealars 4–5. 4.5 (6), supraalars absent, preepisternals absent, scutellars multiserial 12–26, 18.1 (9) in number.

Wing ( Fig. 2 C): Costal extension absent, R2+3 running along R1 and ending from 1/7 of distance from end of R1 to R4+5, anal lobe slightly produced, VR 1.00–1.11, 1.05 (16), squamals 19–30, 23 (14) in number, setae on vein R1 1–9, 3.4 (16), R4+5 0–3, 1.0 (16) in number, the other veins without setae. Wing membrane bare, without pigmentation.

Legs: Leg measurements and proportions as in Table 2 . A few sensilla chaetica on basal part of ta1 of mid leg ( Fig. 2 D), 2–5, 3.4 (11) in number, of hind leg 2–5, 3.6 (10). Two pseudospurs present on tip of ta1 and ta2 of mid and hind legs. Pulvilli apparently absent, empodium as long as half length of claw with 3 ventro-basal long setae, tip of claw palmate.

tibial spur (p2, p3 inner) tibial spur (p2, p3 outer) tibial comb spines (n) LR BV SV 50–70 57 (16) 0.69–0.76 1.41–2.20 1.32–2.64 0.73 (15) 2.09 (15) 2.44 (15) 28–48 35 (16) 12–25 20 (16) 0.49–0.57 2.47–2.77 3.48–4.00 0.53 (15) 2.62 (15) 3.76 (15) 60–80 67 (16) 18–30 23 (15) 11–12 11.5 (16) 0.55–0.61 2.54–2.76 3.12–3.42 0.58 (14) 2.64 (14) 3.25 (14) Hypopygium ( Fig. 3 A): Anal point reaching slightly beyond end of tergite IX, narrowly triangular, tapering toward rounded apex, with few lateral setae arising from clear pores; sternapodeme with weak oral projection, virga consisting of 3–6, 5 spines (13) of 22–45, 30μm long (15); superior volsella weak and indistinct, inferior volsella double, dorsal part rounded, ventral part setigerous forming low hump along median ridge of gonocoxite ( Fig. 3 B). Gonostylus straight, long and parallel sided, with well developed crista dorsalis.

Figures

FIGURE 1. Orthocladius (Euorthocladius) piloculatus sp. nov. A: apical part of antenna (50 μm); B: sensilla chaetica on flagellomere (100 μm); C: head (200 μm); D: hairy eye (50 μm).

FIGURE 2. Orthocladius (Euorthocladius) piloculatus sp. nov. A: antepronotum (200 μm); B: part of thorax showing absence of acrostichals (200 μm); C: wing (1000 μm); D: sensilla chaetica on basal tarsomere of mid leg (50 μm).

FIGURE 3. Orthocladius (Euorthocladius) piloculatus sp. nov. A: hypopygium (200 μm); B: superior and inferior volsellae. Vi: virga, SVo: superior volsella, IVo: inferior volsella, dl: dorsal lobe, vl: ventral lobe (100 μm).

Tables

TABLE 2. Lengths (in μm) and proportions of legs in adult male of Orthocladius (Euorthocladius) piloculatus sp. nov.

fe	ti	ta1	ta2	ta3	ta4	ta5
p1 670–850 760 (15)	780–1000 897 (16)	560–760 658 (15)	390–500 446 (15)	280–350 309 (15)	180–230 205 (15)	110–150 125 (15)
p2 720–930 825 (16)	730–950 843 (16)	400–500 445 (15)	270–325 298 (15)	195–240 218 (15)	110–160 140 (15)	110–140 119 (15)
p3 780–1000 890 (16)	890–1120 1015 (16)	510–680 593 (14)	300–400 359 (14)	240–310 287 (14)	140–195 174 (14)	110–150 135 (14)
continued.