Rheochlus latisetus, Siri & Brodin & Ilpla & Conicet-Cct & Unlp, 2014

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 : 365-367

Rheochlus latisetus sp. nov.

( Figs 1–9 )

Type material. HOLOTYPE: adult J, “ ARGENTINA / Rio Negro province / Nahuel Huapi National Park / Blest stream / 41º09’26’’S / 71º49’20’’W / 21.x.2006 / M.Donato leg / sweep net ” ( MLPA) . ALLOTYPE: adult ♀, same data as for holotype ( MLPA) . PARATYPES: 1 J, same data as for holotype ( MLPA) ; 1 adult J and 1 adult ♀, “ ARGENTINA / Rio Negro province / Mallín La Cortadera / 41°05’13’’S / 71°48’26’’W, 769 m. a.s.l. / 14-xii-2006 – 08-i-2007 / Malaise trap / Garré & Montes de Oca cols.” ( MLPA) .

Diagnosis. Rheochlus latisetus sp. nov. male adult is characterized by: maxillary palp more or less reduced; wing almost bare with few setae present on veins R, R 1 and R 4+5; short dorsal keel on gonocoxite; distinctive wide and stout “p” seta on gonostylus; apical lobe of gonostylus long, subapical lobe short and blunt, both lobes ending in a narrow apical seta (“t” seta”); setae “x” and “y” close to the mid section of the apical lobe. The female adult is characterized by: maxillary palp more or less reduced; flagellomeres 2–12 short and about as long as wide; ultimate flagellomere as long as flagellomeres 8–12 together; wing almost bare; cerci simple.

Description. Male imago (n = 2–3, except when otherwise stated). ( Figs 1–6 ). Total length 1.68–1.93 [1.93] mm, total length/wing length 1.37–1.58 [1.58].

Head ( Figs 1 ). Eyes hairy. Antenna with 14 flagellomeres ( Fig. 2 ), AR 0.44–0.52 [0.44]. Temporal setae 10–12 [10], postorbitals 4–5 [5] on each side. Clypeus with 2 setae. Palpomere lengths (I–V): 14 [14]; 37–41 [41]; 41–44 [44]; 31–35 [35]; 41–44 [44]. Tentorium 100–106 [106] long.

Thorax. Antepronotum with 6 [6] setae (1). Dorsocentrals 11 (1); acrostichals 15–16; prealars 7–8; supraalar 1 (1); scutellars 5–6 [5].

Wing ( Fig. 3 ). 1.22–1.25 [1.22] mm long; 0.46–0.49 [0.46] mm wide; L/ W 2.50 –2.73 [2.68]. VR 0.92–0.96 [0.96]. Width of cell r 1 at the end of vein R 1 100–102 [100]; maximum width of cell r 5 125–143 [125]; r 1 /r 5 0.72–0.80 [0.80]. Brachiolum with 2–3 [2] setae; squama with 2 [2] setae. R with 5–7 [5] setae, R 1 with 5–7 [6] setae, R 4+5 with 3–7 [3] setae, Cu 1 with 2–3 [2] setae; Sc, Cu, M

1+2

, M

3+4

and An without setae.

Legs. Spur of front tibia 35–38 [35] long; spurs of mid tibia 16–22 [22] and 22–24 [24] long; of hind tibia 18–20 [20] and 59–65 [59] long. Apex of ti 1 28–30 [28] wide, of ti 2 26–30 [26] wide, of ti 3 37 [37] wide. Comb with 10–12 [11] spines. Lengths and proportions of legs in Table 3.

Hypopygium ( Fig. 4 ). Tergite IX with 16–20 [20] setae, laterosternite IX with 2–3 [3] setae. Phallapodeme 57–71 [65] long; transverse sternapodeme 55–59 [59] long. Gonocoxite 132–142 [142] long; short basal keel 0.37–0.40 [0.40] times as long as gonocoxite. Gonostylus ( Figs 5–6 ) 73–79 [73] long; apical lobe 33–40 [40] long, apical seta (“t” seta) 12–14 [14] long; subapical lobe 18–20 [18] long, with apical seta (“t” seta) 13–18 [13] long. Seta “p” 41–56 [49] long, 5–7 [7] wide, L/W of seta “p” 7.2–8.0. The “x” and “y” setae discernible, placed close to the mid section of apical lobe. HR 1.79–1.81 [1.81], HV 2.36–2.64 [2.64].

Female imago (n = 1–2) ( Figs 7–9 ). Total length 1.74–1.85 [1.85] mm. Total length / wing length 1.27–1.44 [1.44]. Wing length / profemur length 3.37–4.17 [3.37].

Head. Eyes hairy. Antenna with 13 flagellomeres ( Fig. 7 ). Last flagellomere 89–93 [89] long, as long as flagellomeres 8–12 together. Flagellomeres 2–12 short, more or less globose. AR 0.34–0.46 [0.34]. Temporal setae 12–26 [26]; postorbitals 4 on each side; clypeals 2. Palpomere lengths (I–V): 18 [18]; 40–42 [42]; 40–42 [42]; 28–35 [28]; 42–50 [42]. Tentorium 77–83 [77] long.

Thorax. Antepronotum with 5 [5] setae. Dorsocentrals 14–17 [17]; acrostichals 21 [21]; prealars 6–9 [6]; supraalar 1 [1]; scutellars 5–8 [5].

Wing ( Fig. 8 ): length 1.29–1.38 [1.29] mm; width 0.58–0.63 [0.58] mm; L/ W 2.21 –2.22 [2.22]. VR 0.98 [0.98]. Width of cell r 1 at the end of vein R 1 120 [120]; maximum width of cell r 5 150–160 [150]; r 1 /r 5 0.75–0.80 [0.80]. Brachiolum with 2 [2] setae; squama with 2 setae. R with 4–6 [6] setae, R 1 with 9 [9] setae, R 4+5 with 6–16 [16] setae, M 1+2 with 0–1 [1] setae, Cu 1 with 2–3 [3] setae, An with 0–5 [5] setae. Remaining veins bare. C extension 75–80 [80] long.

Legs. Spur of front tibia 27–30 [27] long; spurs of mid tibia 24–25 [24] and 18–20 [20] long; of hind tibia 22 [22] and 63–75 [75] long. Apex of ti 1 28–33 [28] wide, of ti 2 28–30 [28] wide, of ti 3 35–43 [35] wide. Comb with 11–13 [11] spines. Lengths and proportions of legs in Table 4.

Genitalia ( Fig. 9 ). Cercus 63–70 [70] long; noto plus ramus 132–150 [132] long. Seminal capsule 43–58 [43] long. Sternite VIII with 28–32 [32] setae. Tergite IX with 15 [15] setae, and 3 [3] lateral setae. Segment X with 6 [6] setae on each side.

Etymology. Latisetus, from the Latin “ lati- ” meaning broad and “ setus ” meaning hair, referring to the broad and stout “p” seta of the gonostylus.

Distribution. Argentina (Rio Negro Province: Nahuel Huapi National Park).

Figures

Figs 1–9. Rheochlus latisetus sp. nov. 1–6 – male adults: 1 – head; 2 – antenna; 3 – wing; 4 – hypopygium, dorsal view (right) and ventral view (left); 5 – gonostylus: dorsal view (left) and ventral view (right), “p”, “x”, “y” and “t” setae are drawn and referenced; 6 – Photos of gonostylus: dorsal view (left), subapical lobe (middle) and apical lobe (right); the position of each seta is indicated. 7–9 –female adults: 7 – antenna; 8 – wing; 9 – genitalia ventral view, drawing and photo. Scale bars = 100 ȝm. Abbreviations: al – apical lobe of gonostylus, dk – dorsal keel on gonocoxite, “p” – seta at the base of subapical lobe of gonostylus, “t” – subapical setae of the apical and subapical lobes, sa – subapical lobe of gonostylus, “x” – ventral seta of the apical lobe, “y” – dorsal seta of the apical lobe.