Rheochlus insignis Brundin, 1966

Siri, Augusto, Brodin, Yngve, Ilpla, Conicet-Cct & Unlp, 2014, Cladistic analysis of Rheochlus and related genera, with description of a new species (Diptera: Chironomidae: Podonominae), Acta Entomologica Musei Nationalis Pragae 54 (1), pp. 361-375 : 367-368

Rheochlus insignis Brundin, 1966

( Figs 10–14 )

Type material examined. PARATYPES: 2 adult JJand 2 ♀♀, “ CHILE / Cautín province / Río Llancahue at lago Pellaifa / 20-i-1958 / J. Illies col” ( SMNH).

Additional material examined. 1 adultJ and 1 adult ♀, “ ARGENTINA / Río Negro province / Valle del Challhuaco / Mallín de los patos / 41°15’48.6’’S / 71°17’50.3’’W, 1020 m. a.s.l. / 10-i-2009 / Siri A. col / sweep net” ( MLPA).

Redescription. Male imago (n = 2–3) ( Figs 10–12 ). Total length 2.38–3.23 mm, total length / wing length 1.30–1.63.

Head. Eyes hairy. Antenna with 14 flagellomeres ( Fig. 10 ). Ultimate flagellomere 150 long, penultimate 80 long. AR 0.43. Temporals 14, postorbitals 8 on each side. Clypeus with 2–4 setae. Palpomere lengths (I–V): 25; 20–25; 68–70; 45–48; 53. Tentorium 125 long.

Thorax. Antepronotum with 3 setae. Dorsocentrals 19; acrostichals 20; prealars 12; supraalar 1; scutellars 8.

Wing ( Fig. 11 ): length 1.63–1.98 mm; width 0.54–0.69 mm; L/ W 2.81 –2.90. C extension 90 long. VR 0.98–0.99. Width of cell r 1 at the end of vein R 1 115–145 ; maximum width of cell r 5 150–195; r 1 /r 5 0.72–0.79. Brachiolum with 3–7 setae; squama with 9–21 setae. R with 19–44 setae, R 1 with 22–51 setae, R 4 +5 with 27–42 setae, M 1+2 with 32 (1) setae, Cu 1 with 19 (1) setae, An with 8 setae (1). Cells r

4+5

and m

1+2

setose; remaining cells bare.

Legs. Spur of front tibia 48–55 long; spurs of mid tibia 33–45 and 25–28 long; of hind tibia 54–73 and 25–33 long. Apex of ti 1 48–52 wide; of ti 2 50 wide; of ti 3 50–56 wide. Comb with 10–12 spines. Lengths and proportions of legs in Table 3.

Hypopygium ( Fig. 12 ). Tergite IX with 22 setae (1), laterosternite IX with 3 setae (1). Transverse sternapodeme 125 long. Gonocoxite 160–200 long; dorsal keel 0.78–0.82 as long as gonocoxite. Gonostylus 95–120 long; basal portion of gonostylus swollen to nearly spherical; apical lobe 50–63 long, apical seta (“t” seta) 13 long; subapical lobe 19–25 long. Seta “p” 88–90 long, 4–5 wide, L/W of seta “p” 18–22. The “x” and “y” setae discernible, the “x” proximal and the “y” distal to mid section of the apical lobe. HR 1.67, HV 2.03.

Female imago (n = 2–3) ( Figs 13–14 ). Total length 2.24–2.40 mm. Wing length / profemur length 3.29–3.46.

Head. Hairy eyes. Antenna with 13 flagellomeres ( Fig. 13 ). Last flagellomere 83–113 long, broader than the preceding ones; about as long as flagellomeres 10–12. AR 0.18–0.20. Temporal setae 24; postorbitals 8 on each side (1). Palpomere lengths (I–V): 22; 45; 80; 48; 63 (1). Tentorium 88 long.

Thorax. Setation (1): Antepronotum with 4 setae. Dorsocentrals 27; acrostichals 20; prealars 5; supraalar 1; scutellars 10.

Wing ( Fig. 14 ): length 1.78–2.21 mm; width 0.68–0.92 mm; L/ W 2.40 –2.60. C extension 63–88 long. VR 0.97–1.02. Width of cell r 1 at the end of vein R 1 130–180 ; maximum width of cell r 5 160–230; r 1 /r 5 0.78–0.81. Brachiolum with 3–7 setae; squama with 4–7 setae. R with 25–41 setae, R 1 with 33–70 setae, R 4 +5 with 73–135 setae, M 1+2 with 39–83 setae, Cu 1 with 24–45 setae, An with 24 (1) setae. Almost all cells setose .

Legs. Spur of front tibia 35–50 long; spurs of mid tibia 23–28 long and 28 long; of hind tibia 60–75 long and 23 long. Apex of ti 1 40–50 wide; of ti 2 40 (1) wide; of ti 3 45–60 wide. Comb with 10–11 spines. Lengths and proportions of legs in Table 4.

Genitalia. Cercus 70–75 long, broadly triangular; noto plus ramus 200 long. Seminal capsule 40–58 long. Sternite VIII with +65 (1) setae. Tergite IX with 34 (1) setae. Segment X with 9 (1) setae on each side.

Distribution. Chile (Cautín province), Argentina (Rio Negro Province: Nahuel Huapi National Park).

Figures

Figs 10–19. Rheochlus species adults. 10–12 – R. insignis Brundin, 1966, male: 10 – antenna; 11 – wing; 12 – hypopygium, dorsal view (right) and ventral view (left). 13–14 – R. insignis Brundin, 1966, female: 13 – antenna; 14 – wing. 15 – R. prolongatus Brundin, 1966, male wing. 16–19 – R. wirthi (Freeman, 1961): 16–17 – male (16 – antenna, 17 – wing); 18–19 – female (18 – antenna, 19 – wing). Scale bars = 100 ȝm.