Onconeura analiae, Donato, Mariano, Siri, Augusto & Mauad, Melina, 2012

Donato, Mariano, Siri, Augusto & Mauad, Melina, 2012, Description of a new species of the genus Onconeura Andersen et Saether (Diptera: Chironomidae) from Argentina with a cladistic analysis of the genus, Zootaxa 3580, pp. 43-55 : 44-52

Onconeura analiae sp. n.

Type material. Holotype male, ARGENTINA, Buenos Aires, Sierra de la Ventana, A° Napostá, 38º 08’ 45.5’’S – 62º 05’ 35.8’’W, 566 m asl, 10.XII.2010, sweep net, M, Donato, A. Siri, F. Spaccesi. Allotype: 1 female, ARGENTINA, Buenos Aires, Sierra de la Ventana, C° Bahía Blanca, A° unnamed, 38° 04´03.5´´S –61°58´33.9W, 479 m asl, 20–22.V.2011, Malaise trap, M, Donato, A. Siri, F. Spaccesi. Paratypes (all from Argentina): 2 males, same data as holotype except 11.I.2011; 1 male, same data as holotype except 3.XI.2011; 3 females, same data as allotype; 1 female, Buenos Aires, Sierra de la Ventana, A° Cueva del Toro, 31º 01’ 09.5’’S – 62º 00’ 55.9’’W, 556 m asl, 22.V.2011, sweep net, M, Donato, A. Siri, F. Spaccesi; 1 pharate male with attached larval exuvia, Buenos Aires, Sierra de la Ventana, Aº Cueva del Toro, 38º 01’ 19.0’’S – 62º 01’ 33.3’’W, 672 m, 22.V.2011, Sweep net, M, Donato, A. Siri, F. Spaccesi; 1 pharate female, Buenos Aires, Sierra de la Ventana, Aº Ventana, 38º 03’ 09.0’’S – 62º 01’ 08.8’’W, 782 m, 11.XII.2010, hand net, M, Donato, A. Siri, F. Spaccesi; 6 pupal exuviae, same data as holotype; 1 larva, Buenos Aires, Sierra de la Ventana, Aº Napostá, 38º 08’ 43.8''S – 62º 05’ 33.5’’W 566m, 20.V.2011, D-net, M, Donato, A. Siri, F. Spaccesi; 1 larva, Buenos Aires, Sierra de la Ventana, Aº Cueva del Toro, 38º 01’ 09.6’’S – 62º 00’ 56.3’’W, 561 m, 22.V.2011, D-net, M, Donato, A. Siri, F. Spaccesi.

Etymology. Named in honour of Dr. Analia Constancia Paggi, the first Argentinian chironomidologist; the name should be treated as a noun in the genitive case.

Diagnosis. Adult male is distinguished from all other species of the genus by the combination of the following characters: 12 flagellomeres, anal lobe of wing present, inferior volsella posterior margin concave, LR1 1.38–1.46, LR2 1.67–1.74, LR3 1.48–1.55. The adult female is separable by the shape of the labia and apodeme lobe, presence of a sclerotized bar-like structure between dorsomesal lobes, LR1 1.36–1.57, LR2 1.61–1.73, LR3 1.16–1.5, BV1 5.45–5.64. The pupa is separable by the sclerotized, dark brown posterior corner of segments IV-VII and frontal setae very short and cone-shaped, located in precorneal area.

Description.

Adult male (n = 4)

Total length 1.56–1.89 [1.56] mm. Wing length 0.89–1.08 [0.89] mm. Total length / wing length 1.75–1.92 [1.75]. Wing length / length of profemur 2.78–2.97 [2.97].

Color (specimen preserved in alcohol). Thorax brownish with brown vittae, scutellum, postnotum and preepisternum. Abdomen and legs brownish.

Head. Antenna with [12] flagellomeres ( Fig. 1 ), AR 0.51–0.55 [0.54], ultimate flagellomere 173–207 [180] long. Temporal setae: [2] postorbitals. Clypeus with 12–15 [12] setae. Tentorium 132–149 [141] long; 21–24 [22] wide. Stipes 90–105 [100] long; 4–7 [7] wide. Palpomere lengths: 27–32 [32], 34–46 [37], 54–61 [56], 78–90 [78], 112–137 [112].

Thorax. Lateral antepronotals 2–3 [3] (3), dorsocentrals 13–14 [13], prealars 2–3 [3], supralar [1] (2), scutelars 4–5 [5].

Wing ( Fig. 2 ). VR 1.76–1.9 [1.83]. Clavus [23]–28 wide; ending 340–440 [340] from arculus. Cubital / wing length 0.48–0.5. Clavus / wing length 0.38–0.41 [0.38]. Brachiolum with 1 seta.

Legs. Fore trochanter as in Figure 3 . Spur of fore tibia 29–41 [29] long; spurs of middle tibia 12–17 [12] and 20–22 [20] (3) long; spurs of hind tibia 12–15 [15] and 29–37 [37] long. Width of apex of fore tibia 27–29 [27]; of middle tibia 24–29 [24]; of hind tibia 32–34 [32]. Tibial comb with 10–12 [10] setae. Legs measurements as in Table 1.

Abdomen. Number of setae on tergite II 8–10 [9], TIII 8–10 [10], TIV 7–9 [8], TV 6–9 [8], TVI 5–6 [5], TVII [5], TVIII 7–10 [7].

Hypopygium ( Figs 4–5 ). Tergite IX with 10–15 [10] small setae. Superior volsella low. Inferior volsella with posterior margin concave. Phallapodeme 39–43 [41] long; transverse sternapodeme 38–47 [41] (3) long. Gonocoxite 113–136 [124] long. Gonostylus 41–52 [41] long; megaseta 8–11 [9] long. HR 2.31–3.02 [3.02], HV 3.38–3.8 [3.8].

Adult female (n = 4)

Total length 1.78–1.91 [1.91] (3) mm. Wing length 1.19–1.28 [1.28] mm. Total length / wing length 1.45–1.5 [1.5] (3). Wing length / length of profemur 3.19–3.39 [3.19].

Head. AR 0.42–0.49 [0.43]. Flagellomeres length: 49–51 [51], 37–39 [37], 35–39 [39], 37–44 [44], 67–80 [73]. Temporal setae 7–8 [7]: including 2–3 [2] inner verticals, 2–3 [3] outer verticals and 2–3 [2] postorbitals. Clypeus with 13–18 [13] setae. Tentorium 88–139 [127] long, 17–20 [20] wide. Stipes length 98–107 [98], 5–7 [7] wide. Palpomeres length: 29–41 [29], 41–44 [44], 61–63 [61], 88–95 [95], 124–134 [127].

Thorax chaetotaxy. Lateral antepronotals 3–6 [4], dorsocentrals 12–16 [16], prealars 3–4 [3], supralar [1], scutelars 4–6 [6].

Wing ( Fig. 6 ). VR 1.7–1.87 [1.74]. Clavus ending at 650–713 [713] from arculus; with 13–19 [14] setae. Cubital / wing length 0.47–0.48. Clavus / wing length 0.55–0.57 [0.56]. Brachiolum with 1 seta.

Legs. Spur of fore tibia 24–34 [27] long; spur of middle tibia 10–20 [15] and 22–27 [27] long; spurs of hind tibia 10–17 [12] (3) and 34–49 [49] (3) long. Width of apex of fore tibia 24–37 [34]; of middle tibia 34–37 [34]; of hind tibia 37–49 [43] (3). Sensilla chaetica on tarsomere 1 of middle leg 8–11 [10], of hind leg 15–17 [16] (3). Tibial comb with 11–13 [12] (3) setae. Legs measurements as in Table 2.

TABLE 2. Lengths (in µm) and proportions of legs of Onconeura analiae sp. n. (female) (n = 4, except when otherwise stated). fe ti ta1 ta2 ta3

P1 350–400 [400] 380–440 [440] 280–320 [320] 95–110 [110] 60–70 [70]

P2 460–500 [500] 450–520 [520] 280–310 [310] 130–150 [150] 60–80 [80]

P3 380–430 [430] (3) 450–520 [520] (3) 300–440 [350] (3) 170–190 [190] (3) 60–75 [75] (3) ta4 ta5 LR BV SV

P 1 30–35 [30] 50 [50] 1.36–1.57 [1.38] 5.45–5.64 [5.52] 2.61–2.93 [2.63]

P 2 30–40 [40] 40–50 [50] 1.61–1.73 [1.68] 4.93–5.50 [4.93] 3.25–3.4 [3.29]

P 3 30–40 [40] (3) 50 [50] (3) 1.16–1.50 [1.49] (3) 4.26–4.86 [4.26] (3) 2.09–2.77 [2.71] (3) Abdomen. Number of setae on tergite II 5–9 [9] (3), TIII 10–11 [11] (3), TIV 8–11 [9], TV 8–10 [10], TVI 6–10 [8], TVII 5–8 [5], TVIII 8–9 [9], TIX 11–16 [16].

Genitalia ( Figs 7–10 ). Gonocoxite with 4–7 [7] setae. Sternite VIII with 13–17 [14] setae. Cercus 71–80 [75] long. Seminal capsules 46–56 [50] long, 38–40 wide. Notum 129–142 [142] (3) long. Dorsomesal lobes well sclerotized, with a sclerotized bar-like structure between them ( Fig. 8 ). Apodeme lobe and labia in Figures 9 and 10 respectively.

Pupa (n = 6)

Total length 2.61–2.86 mm.

Cephalothorax. Frontal seta very short and cone-shaped located in a shallow pit between antennal sheaths ( Fig. 11 ). Longest median antepronotals 56–98 (5). Longest lateral antepronotals 17–27. Longest precorneal seta 78–100. One sensillum near precorneal setae. Dc1 49–61 long; Dc 2 20–34 (5) long; Dc 3 12–17 (3) long; Dc4 132–154 long. Distance between Dc1 and Dc 2 8–27; Dc2 and Dc3 144–190; Dc3 and Dc 4 2–10. Wing sheath with two to three rows of pearls.

Abdomen ( Figs. 12–14 ). Tergite I and sternite I without shagreen. Tergites II–IX with fine shagreen. Sternite II–VIII with fine shagreen but weaker than that of tergites. Tergite II with an apical band of spinules, tergites III–VIII with an apical band of spines. Sternite IV with a posterior band of spinules, sternites V–VIII with an apical band of spines, those located in the center anteriorly directed. Posterior corner of segments IV–VII sclerotized and dark brown pigmented. Conjunctive TII/III with 2–5 hooklets; TIII/IV with 5–9 hooklets; TIV/V with 6–10 hooklets; TV/VI with 5–8 hooklets; TVI/ VII with 4–6 hooklets. O-setae present ventral and dorsal in all segments (not drawn). Segment I with 4 D-setae, 2 L-setae, the anterior one very long, without V-setae. Segments II–IV with 4D and 4V. Segments V–VII with 5 D and 4 V. Segment II with 3 L-setae, segments III–VII with 4 L-setae. Segment VIII with 2 D, 1 V and 3 L- setae.

Anal lobe 205–241 long ( Fig. 12 ). Anal lobe fringe with lateral 3–4 stout and shorter setae and median 3–5 taeniate setae; taeniate setae 137–145 ìm long, one median spur. Anal macrosetae 41–56 long; median setae 207–305 (2) long.

Larva (n = 3)

Head. Capsule length 346–450, width 183–250. Ventral head length 266–290. Ventral head length / width 1.16–1.45. SI bifid. Median tooth of mentum as long as adjacent teeth ( Fig. 15 ). Distance between seta submentalis 46–58. Antenna ( Fig. 16 ). AR 2.81–2.97. Length of antennal segments: 76–89, 17–20, 3, 2, 5; basal segment width 14–23; antennal blade 22–25 (2) long; ring organ at 20–30 from the base of first antennal segment. Mandible ( Fig. 17 ) length 87–97.

Abdomen. Procercus 25–29 high and 22–23 wide. Subbasal seta on posterior parapod simple, 30–33 (2) long.

Remarks on habitat. Immatures of O. analiae were collected at Napostá, Ventana and Cueva del Toro streams, Buenos Aires, Argentina. Water analysis showed the following values (the ranges express the values from the three sites): N-NO2 0.002–0.005 (mgN/l); N-NO3 0.072–0.079 (mgN/l); P-PO4 0.022–0.069 (mg P/l); DBO 2–4 (mgO/l); DQO 7–14 (mgO/l); pH 6.30–8.14; conductivity 81–280 (ìS/cm); dissolved oxygen 8.64–13.98 (mgO/l) or 46.5–91.9 (%); temperature 10.9–23.0 (ºC).

Cladistic analysis. The analysis under equal weights yielded one tree (L = 77.277; CI = 0.71; RI = 0.58) ( Fig. 18 ) and the analysis under every concavity value of implied weights yielded the same tree topology. This analysis suggests that the genus Onconeura is not a monophyletic group since Tempisquitoneura merrillorum is inside the genus. This clade is supported by the character ‘pupal apex of anal lobe with one or more spines' [character 20 (1)] (this character is absent in T. merrillorum ), ‘larval antenna 1/3 as long as head capsule or shorter’ [character 21 (1)] (but T. merrillorum possesses the character state 2, see Appendix) and ‘body setae long, often stout and dark’ [character 27 (1)] (in T. merrillorum this character reverts to state 0). The species T. merrillorum is the sister group of O. undecimata supported by the 'supralar seta present' [character 12 (1)]. The analysis performed with this character inactivated moved T. merrillorum as the sister group of the clade O. analiae plus O. similispina . In this topology, the synapomorphy supporting this relationship is the character 'presence of preapical sensilla chaetica on male antennal apex' [character 10 (1)]. The character support measures of this cladogram show interesting results ( Fig. 21 ). The terminal clades with the best support are those of Ubatubaneura atlantica plus Corynoneura fortispicula , O. cascatinha plus O, oncovolsella , and O. analiae plus O. similispina . The results of Absolute frequencies and relative Bremer support are according with the most parsimonious tree found, but GC values and absolute Bremer support shows Onconeura as monophyletic with very low support and T. merrillorum as the sister group.

Due to the results obtained in the analysis performed, a second analysis was performed but forcing the monophyly of Onconeura using the same search strategy. The cladogram obtained is shown in Figure 19 (L = 77.367, CI = 0,71, RI = 0.58). The analysis under implied weights yielded two different topologies (in concavities 5 to 9 and 10 to 16 respectively) and are summarized in the strict consensus ( Fig. 20 ). Using the option in TNT to prune the trees in order to find an improvement in the resolution of the Onconeura clade, two nodes were gained by the pruning of O. japi and O. desertica and the cladogram obtained is ( O. semifimbriata (( O. similispina - O. analiae ) ( O. undecimata ( O. oncovolsella - O. cascatinha )))). These relationships are supported by continuous characters only. The pruning of the node ( O. similispina - O. analiae ), O. undecimata and O. semifimbriata gained one node and the resulting cladogram is ( O. desertica ( O. japi ( O. oncovolsella - O. cascatinha )). These relationships are also supported by continuous characters.

The clades ( O. similispina - O. analiae ) and ( O. oncovolsella - O. cascatinha ) are the only clades common to all the analyses performed in this study for the genus Onconeura . The former clade is supported by the synapomorphies 'LR1 0.92–1.00' [character 5] and 'presence of preapical sensilla chaetica on male antennal apex' [character 10 (1)]. The latter clade is supported by the synapomorphies 'AR 0.38–0.40' [character 0] and 'superior volsella well developed' [character 15 (2)].

All the analyses performed show an important number of homoplastic characters that is manifested by the inclusion of T. merrillorum as part of the genus Onconeura , the difference of only decimals in the length of the cladograms when Onconeura clade was forced, and the finding of several floating taxa when cladograms were pruned.

Figures

FIGURE 21. Support measures calculated for the tree obtained under equal weights.

FIGURES 1 – 5. Onconeura analiae sp. n. Male adult: 1, apex of antennae; 2, foretrochanter; 3, wing; 4, hypopygium with tergite IX; 5, hypopygium with tergite IX removed, right dorsal view, left ventral view.

FIGURES 6 – 10. Onconeura analiae sp. n. Female adult: 6, wing; 7, female genitalia, ventral view; 8, sclerotized bar-like structure between dorsomesal lobes; 9, apodeme lobe; 10, labia.

FIGURES 11 – 14. Onconeura analiae sp. n. Pupa: 11, frontal seta; 12, anal lobe; 13, abdomen, dorsal view; 14, abdomen, ventral view.

FIGURES 15 – 17. Onconeura analiae sp. n. Larva: 15, mentum; 16, antenna; 17, mandible.

FIGURES 18 – 20. Results of the cladistic analysis of the genus Onconeura Andersen et Saether. (18) Cladogram obtained under equal weights (L = 77.277; CI = 0.71; RI = 0.58). (19) Cladogram obtained forcing the monophyly of Onconeura under equal weights (L = 77.367, CI = 0.71, RI = 0.58). (20) Strict consensus tree calculated for each tree obtained forcing the monophyly of Onconeura under implied weights.