Allocladius neobilobulatus (Paggi) Andersen & Saether & Mendes, 2010

Andersen, Trond, Saether, Ole A. & Mendes, Humberto F., 2010, Neotropical Allocladius Kieffer, 1913 and Pseudosmittia Edwards, 1932 (Diptera: Chironomidae) 2472, Zootaxa 2472 (1), pp. 1-77 : 14-17

Allocladius neobilobulatus (Paggi) comb. n.

( Figs 27–37 )

Pseudosmittia neobilobulata Paggi, 1993: 172 .

Material examined. ARGENTINA: Buenos Aires, Laguna de Lobos , 2 male paratypes, 15.vi.1989, A. Paggi ( ILLP) . CHILE: Región VI, Río Claro South of Molina , 35º09.171'S, 71º17.054'W, 212 m a.s.l., 2 males, 18.xi.1998, hand net, T. Andersen ( ZMBN) . Región XI, Laguna Cea , 20 km Southwest of Coihaique, 4 males, 14.ii.1996, hand net, T. Andersen ( ZMBN) . BOLIVIA: Between Oruru and Cochabamba, side arm of a dam, 3.000 m a.s.l., 1 male, 1 mature male pupa, 2 pupal exuviae, 14.vii.1976, E.J. Fittkau ( ZSM) .

Diagnostic characters. The two broad, large and lobe-like pars ventralis will separate the male imago from all other Allocladius species. The pupa is very similar to that of the Holarctic A. nanseni (Kieffer) , but can be distinguished by having a papilla on the genital sac which is nearly twice as long as wide and more numerous spinules on the posterior sternal conjunctives.

Male (n = 8–10, except when otherwise stated). Total length 1.85–2.74, 2.11 mm. Wing length 1.08–1.67, 1.25 mm. Total length / wing length 1.45–1.82, 1.66. Wing length / length of profemur 2.82–3.16, 2.96.

Coloration. Brownish black.

Head. AR 0.82–1.23, 0.99. Ultimate flagellomere 281–443, 340 µm long. Temporal setae 4–9, 6; consisting of 0–3, 2 inner verticals; 0–3, 2 outer verticals and 0–4, 2 postorbitals. Clypeus with 4–9, 6 setae. Tentorium, stipes, and cibarial pump as in Figure 27 . Tentorium 82–127, 106 µm long; 20–30, 24 µm wide. Stipes 93–127, 105 µm long; 27–39, 32 (6) µm wide. Palpomere ( Fig. 28 ) lengths (in µm): 16–25, 20; 27–43, 35; 45–75, 56; 52–82, 59; 70–109, 83. Third palpomere with 1 lanceolate sensilla clavata; 9–11, 11 (7) µm long.

Thorax ( Fig. 29 ). Median antepronotal lobes well developed; antepronotum with 0–1, 1 lateral seta. Dorsocentrals 7–8, 7; acrostichals 4–8, 6, simple or scalpellate; prealars 2–3, 3; supraalar 0–1, 0. Scutellum with 5–8, 7 setae.

Wing ( Fig. 30 ). VR 1.27–1.72, 1.35. Anal lobe projecting. Costal extension 0–50, 13 µm long. R 4+5 ending above apex of M 3+4; Cu 1, slightly sinuate. Brachiolum with 1 seta; R with 2–3, 2 setae; other veins bare.

Legs. Spur of fore tibia 34–47, 39 µm long; spurs of mid tibia 18–34, 21 µm and 11–19, 14 µm long; of hind tibia 31–43, 36 µm and 9–18, 14 µm long. Width at apex of fore tibia 22–29, 25 µm; of mid tibia 20–34, 25 µm; of hind tibia 27–45, 35 µm. Comb of 11–14, 13 setae; longest 20–40, 28 µm long; shortest 15–19, 16 µm long. Length and proportions of legs as in Table 5.

Hypopygium ( Figs 31–32 ). Anal point 11–43, 24 µm long, tapering to pointed apex; tergite IX with 10– 24, 15 setae including setae on anal point. Laterosternite IX with 2–5, 4 setae. Phallapodeme 59–79, 70 (7) µm long. Transverse sternapodeme 45–75, 57 µm long, with weak oral projections. Virga 9–18, 13 µm long; plate-like. Pars ventralis ( Fig. 33 ) double, 75–120, 93 µm long; 34–71, 42 µm wide; reaching to 0.50–0.76 gonocoxite length. Gonocoxite 140–179, 160 µm long. Inferior volsella reaching to 0.65–0.69 gonocoxite length; no apparent posterior lobe. Gonostylus 61–79, 68 µm long; megaseta 6–9, 8 µm long. HR 2.07–2.51, 2.36. HV 2.91–3.88, 3.22.

Pupa (n = 2). Total length 3.38–3.42 mm. Exuviae tinged with brownish yellow along margins of cephalothorax and anal segments, particularly on margin of wing sheath and male genital sac.

Cephalothorax ( Figs 34–35 ). Frontal apotome with some rugulosity, without warts, with frontal setae. All cephalothoracic setae about 45–85 µm long. Distance between Dc 1 and Dc 2 9–10 µm, between Dc 2 and Dc 3 14–25 µm, between Dc 3 and Dc 4 50–55 µm.

Abdomen ( Figs 36–37 ). Tergite I bare; T II–VIII with strong anterior and posterior shagreen, with weaker shagreen covering most of remaining tergites; T IX with strong median shagreen covering most of segment. Sternites I–II bare; S III–V with weak median shagreen, S VI–VII with spinules in anterior 1/3; S VIII with spinules in anterior 1/2; S IX with lateral shagreen. Tergal conjunctive III/IV with 38–84 spinules, IV/V with 137–160, V/VI with 110–150, VI/VII with 90–115 spinules. Sternal conjunctive III/IV with 4–10 spinules, IV/V with 78–100, V/VI with 130–165, VI/VII with 155–200, VII/VIII with 110–119, VIII/IX with 43 spinules in male pupa, none in female pupa. Anal segment with single 27–37 µm long basal seta, three 27–37 µm long apical setae and single 18 µm long median seta. Genital sac of male overreaching anal segment by 96 µm; of female with apical papilla nearly twice as long as wide (papilla also indicated to varying degree in male).

Remarks. The double pars ventralis is unique among orthoclads. However, the pupa is hardly separable from that of the Holarctic A. nanseni (Kieffer, 1926) .

Distribution and biology. The species is known from two localities in Argentina ( Paggi 1993), a high mountain dam in Bolivia and two localities in southern and central Chile where it has been netted along the banks of lakes and rivers. The altitude range is from about 200 to 3.000 m a.s.l.

Figures

FIGURES 27–33. Allocladius neobilobulatus (Paggi, 1993) comb. n., male. 27—tentorium, stipes, and cibarial pump; 28—palp; 29—thorax; 30—wing; 31—hypopygium, dorsal aspect; 32—hypopygium with anal point and tergite IX removed, dorsal aspect to the left, ventral aspect to the right; 33—pars ventralis.

FIGURES 34–37. Allocladius neobilobulatus (Paggi, 1993) comb. n., female pupa. 34—frontal apotome; 35—thorax; 36—tergites; 37—sternites with detail of the papilla on the genital sac.