Onconeura undecimata, Andersen, Trond & Saether, Ole A., 2005

Andersen, Trond & Saether, Ole A., 2005, Onconeura, a new Neotropical orthoclad genus (Chironomidae, Orthocladiinae), Zootaxa 957, pp. 1-16 : 7-13

publication ID

https://doi.org/ 10.5281/zenodo.171214

DOI

https://doi.org/10.5281/zenodo.5632358

persistent identifier

https://treatment.plazi.org/id/AA168783-FFAC-E91D-FEED-B84A39F432C2

treatment provided by

Plazi

scientific name

Onconeura undecimata
status

sp. nov.

Onconeura undecimata View in CoL new species

( Figs. 1 View FIGURE 1 A–H, 2A–I, 3A–E)

Type material. Holotype male, CHILE: Region VI, Rio Mataquito west of Curico, 34°59.393'S, 71° 25.913W, 150 m a.s.l., 18.xi.1998, net, T. Andersen ( ZMBN Type no. 290). Paratypes: Allotype female, Region Metropolitana, Cajon del Maipo, Puente el Yeso, 33°47.127'S, 70°13.625'W, 1.842 m a.s.l., 16.ii.1999, net, T. Andersen; 3 males as for holotype; 7 mature male pupae, 5 mature female pupae, 89 pupal exuviae as for holotype, except driftnet; 14 males as for allotype; 8 males as for allotype, except 26.i.1996; 41 pupal exuviae, Region Metropolitana, Cajon del Maipo, Rio Vulcan at Los Valdes, 33°49.682'S, 70° 03.260W, 1.924 m a.s.l., 10.xi.1998, driftnet, T. Andersen; 17 pupal exuviae, Region VI, Rio Claro south of Molina, 35°09.171'S, 71°17.054'W, 212 m a.s.l., 18.xi.1998, driftnet, T. Andersen.

Diagnostic characters.The imagines are separable from those of O. semifimbriata by having 11 flagellomeres in the male, larger size, and darker coloration without distinctly ringed legs. The pupa is distinguished by having a reduced frontal seta, larger hooklets on tergal conjunctives, and anal lobe with 16–21 taeniae in the fringe, of which the anterior ones are short and spine­like and the preapical ones very long.

Etymology. From the Latin undecim, eleven, and the suffix ­ atus, equipped with, referring to the eleven flagellomeres.

Male imago (n = 10)

Total length 1.68–2.09, 2.88 mm. Wing length 0.90–1.18, 1.08 mm. Total length/wing length 1.69–1.87, 1.75. Wing length/length of profemur 2.71–2.98, 2.87. Thorax yellowish brown with blackish brown vittae, scutellum, postnotum, preepisternum, parts of anterior and median anepisternum II and part of epimeron II. Legs with pale trochanter and in most specimens slightly paler basiventral parts of femora and median parts of hind tibia and hind metatarsus.

Head ( Fig. 1 View FIGURE 1 A). AR 0.60–0.71, 0.66. With 11 flagellomeres, ultimate flagellomere 195–263, 231 m long ( Fig. 1 View FIGURE 1 C). Temporal setae 3–5, 4; including 1 inner vertical, 1–2, 2 outer verticals and 1–2, 1 postorbital. Clypeus with 10–16, 12 setae. Tentorium, stipes, and cibarial pump as in Fig. 1 View FIGURE 1 B. Tentorium 116–158, 141 m long; 19–34, 26 m wide. Stipes 90–120, 110 m long; 26–38, 29 m wide. Palpomere lengths (in m): 26–41, 35; 34–45, 40; 60–75, 69; 83–109, 96; 109–141, 124. Third palpomere with 1 sensilla clavata.

Thorax ( Fig. 1 View FIGURE 1 D). Antepronotum with 4–7, 6 setae. Dorsocentrals 12–19, 15; prealars 3, supraalar 1. Scutellum with 6–8, 7 setae.

Wing ( Fig. 1 View FIGURE 1 F). VR 1.68–1.83, 1.75. Clavus 26–45, 35 µm wide; ending 128–169, 153 µm from arculus; with 0–1, 1 seta at apex.

Legs ( Fig. 1 View FIGURE 1 E). Spur of front tibia 34–41, 38 m long; spurs of middle tibia 23–28, 25 and 13–19, 18 m long; of hind tibia 38–49, 45 and 17–23, 21 m long. Width at apex of front tibia 28–34, 31; of middle tibia 26–34, 31 m; of hind tibia 34–39, 37 m. Length (in m) and proportions of legs as in Table 1 View TABLE 1 .

Hypopygium ( Fig. 1 View FIGURE 1 G–H). Tergite IX with 12–21, 17 minute setae; laterosternite IX with 2–3, 3 setae. Phallapodeme 49–56, 53 m long; transverse sternapodeme 30–53, 40 m long. Gonocoxite 109–143, 124 m long; superior volsella 8–15, 11 m wide, barely joined basally. Gonostylus 49–60, 56 m long; megaseta 9–11, 10 m long. HR 2.18–2.38, 2.24; HV 3.06–3.73, 3.38.

Female imago (n = 1, except when otherwise stated)

Total length 1.73 mm. Wing length 0.98 mm. Total length/wing length 1.77. Wing length/length of profemur 3.04. Coloration patterns as in male, but slightly more pale.

Head ( Fig. 2 View FIGURE 2 A). AR 0.38–0.53, 0.46 (5). Flagellomere lengths (in m, n = 5): 38–45, 44; 26–36, 34; 30–36, 34; 34–36, 35; 38–64, 57. Temporal setae 4–5 (2), including 1–2 (2) inner verticals, 2–3 (2) outer verticals, and 1 (2) postorbital. Clypeus with 11–15, 13 (4) setae. Tentorium, stipes, and cibarial pump as in Fig. 2 View FIGURE 2 B. Tentorium 101 m long, 15 m wide. Stipes 105 m long, 26 m wide. Palpomere lengths (in m): 34, 34, 60, 90, 128.

Thorax ( Fig. 2 View FIGURE 2 C). Antepronotum with 5 setae. Dorsocentrals 11–15, 13 (4); prealars 3 (2), supraalar 1 (2). Scutellum with 4–6 (2) setae.

Wing ( Fig. 2 View FIGURE 2 D). VR 1.74. Clavus 30 µm wide, ending 203 µm from arculus; with 10 setae.

Legs. Spur of front tibia 30 m long, spurs of middle tibia 23 long and lost, of hind tibia 41 and 15 m long. Width at apex of front tibia 30 m, of both middle and hind tibia 34 m. Length (in m) and proportions of legs as in Table 2 View TABLE 2 .

Abdomen. Number of setae on tergite I 8, on each of tergites II–VI 5–7, on VII 4, on VIII 5. Sternite I bare, sternites II–VII with or without 1–2 (3) stronger median seta and with 2 weak posterolateral setae, sternite VIII with 4–8, 7 (5) setae.

Genitalia (n = 6, Fig. 2 View FIGURE 2 E–I). Gonocoxite with 4–6, 5 setae. Tergite IX with 11–15, 13 setae. Cercus 71–105, 82 m long. Seminal capsules 49–56, 54 m long; 38–45, 42 m wide. Notum 43–68, 56 m long.

Pupa (n = 9–10, except when otherwise stated) Total length 2.32–2.66, 2.47 mm.

Cephalothorax. Frontal setae ( Fig. 3 View FIGURE 3 A) taeniate 19–30, 25 µm long; on 11–13, 12 µm high, 9–11, 10 µm wide tubercle. Longest precorneal seta 94–113, 98 µm long; other precorneals and lateral antepronotals less than 40 µm long. Median antepronotals 75–113, 94 µm (4) long; and 38–75, 55 µm (5) long. Anterior dorsocentral (Dc1) 56–75, 65 µm long; Dc2 34–60, 45 µm; Dc 3 11–38, 27 µm (8); Dc4 75­124, 104 (7) µm long and taeniate. Distances (in µm): Dc1­Dc 2 6­15, 10; Dc2­Dc3 124­176, 149, Dc3­Dc 4 4–30, 10. Wing sheath ( Fig. 3 View FIGURE 3 B) with 5–7, 6 rows of pearls.

Abdomen ( Fig. 3 View FIGURE 3 C–D). Shagreen and chaetotaxy as in generic diagnosis. Anal lobe ( Fig. 3 View FIGURE 3 E) 91–221, 209 µm long; with 16–21, 18 taeniae; anterior 3–7, 4 taeniae spine­like, preapical taeniae very long, up to 188–345, 290 µm in length; anal lobe in addition with 1– 3, 2 apical spines. Anal macroseta 56–124, 75 µm long. Median seta 131–206, 171 µm long. Apex of genital sac of male 19–30, 22 µm (5) short of apex of anal lobe; female 49– 64, 55 µm short.

Ecology and distribution. The species has been collected from rivers in central Chile, from 150 meters up to nearly 2000 meters altitude in the western slopes of the Andes. The species can be very abundant in water channels along the larger rivers when they cross the central valley in Chile, and it has also been taken in smaller, faster flowing rivers with gravel and stony substrate in the foothills of the Andes.

TABLE 1. Lengths (in m, as range followed by the mean) and proportions of legs of Onconeura undecimata new species, male (n = 10).

  fe ti ta1 ta2 ta3 ta4 ta5 LR BV SV BR
p1 331–406, 375 335–435, 399 255–312, 291 80–104, 95 47–66, 56 24–33, 29 33–38, 36 0.72–0.76, 0.73 4.72–5.11, 4.99 2.60–2.71, 2.66 1.6–2.2, 2.0
p2 406–501, 456 383–482, 442 250–302, 282 104–132, 109 57–76, 62 24–38, 28 33–43, 39 0.62–0.65, 0.64 4.49–4.98, 4.76 3.11–3.25, 3.18 1.8–2.2, 2.0
p3 331–416, 384 406–501, 458 269–326, 304 142–165, 152 57–76, 68 24–38, 27 38–47, 39 0.63–0.70, 0.67 3.80–4.55, 4.03 2.67–2.91, 2.77 2.0–3.5, 2.6

TABLE 2. Lengths (in m) and proportions of legs of Onconeura undecimata new species, female (n = 1).

fe ti ta1 ta2 ta3 ta4 ta5 LR BV SV BR
p1 331 354 255 104 57 24 38 0.72 4.19 2.65 1.5
p2 416 392 255 80 47 24 38 0.64 5.65 3.19 1.8
p3 369 416 284 132 52 24 38 0.68 4.35 2.77 2.4
ZMBN

Museum of Zoology at the University of Bergen, Invertebrate Collection

Kingdom

Animalia

Phylum

Arthropoda

Class

Insecta

Order

Diptera

Family

Chironomidae

Genus

Onconeura

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