Alotanypus vittigera ( Edwards, 1931 ) Edwards, 1931

Siri, Augusto, Donato, Mariano, Orpella, Germán & Massaferro, Julieta, 2011, Alotanypus vittigera (Edwards) comb. nov.: adult redescription, immature description and a phylogenetic analysis of the genus (Diptera: Chironomidae: Tanypodinae), Zootaxa 2795, pp. 46-64 : 54-61

Alotanypus vittigera ( Edwards, 1931) , comb. nov.

Anatopynia vittigera Edwards 1931: 242 –243, fig. 36b; Spies & Reiss 1996: 82 (listed as unplaced valid species).

Type material (all in NHM). HOLOTYPE male (NHM) L. Nahuel Huapi, Eastern end, Río Negro province, Argentina, 28–31.x.1926, F.W. Edwards. Paratypes. 3 males and 2 females same date as holotype; 1 male and 2 females, L. Correntoso, Río Negro province, Argentina, 18–25.xi.1926, F.W. Edwards; 1 male, Bariloche, Río Negro province, Argentina, 25–28.xi.1926, F.W. Edwards; 1 male, Puerto Montt, Llanquihue province, S. Chile, 24.xii.1926, F.W. Edwards.

Recently collected material. 1 male and 2 females from 41º00´56´´S, 71º49´54´´W, 856 m, Mallín La Heladera, Puerto Blest, PNNH, Río Negro province, Argentina, 07.i–04.ii.2007, Garré & Montes de Oca, Malaise trap, and 3 fourth instar larvae from same site, 04.ii.2007, Garré & Montes de Oca, Kick sample; 4 males with their pupal exuviae and 2 females with their pupal exuviae (all adults emerged same day of collection) from 41º36´06´´S, 71º36´25´´W, temporary pool beside Vertiente stream, Manso Inferior, PNNH, Río Negro province, Argentina, 10.i.2008, G. Orpella; 1 male with its pupal exuviae (adult emerged on 12.ii.2009), 2 females with their pupal exuviae (both adults emerged on 11.ii.2009), 1 prepupa and 2 fourth instar larvae, 41º00´05´´S, 71º50´53´´W, 855 m, Mallín La Heladera, Puerto Blest, PNNH, Río Negro province, Argentina, 11.ii.2009, A. Siri, kick sample.

Emended diagnosis. The diagnosis of Alotanypus vittigera (Edwards) comb. nov. should be emended as follows:

Male: vittae strongly or not indicated; AR lesser or slightly higher than 2.0; anepisternals, preepisternals and postnotals present or absent; LR I = 0.60–0.75.

Pupa: Thoracic seta DC1 shorter or longer than DC3.

Descriptions. Male (n = 5–12, except when otherwise stated) ( Figs. 1–8 )

Total length 5.15–6.23 mm. Total length / wing length 1.61–1.89.

Coloration: Thorax yellowish brown to dark brown, with or without evident vittae. Anepisternum, preepisternum and postnotum dark brown; abdomen as Fig. 1 .

Wing with several dark spots on membrane; macrotrichia above dark spots thick and densely grouped; central section of Cu, cross-veins RM and MCu, FCu and basal section of M3+4 darkened ( Fig. 2 ).

Head: Antenna; AR 1.9–2.1 [1.95]. Temporals multiserial 42–76 [71]; postorbitals bi to multiserial, 21–26 [21]. Clypeus with 7–20 [11] setae. Tentorium 257–274 [270] long (4). Palpomere lengths (1–5) 59–84 [70]; 101– 148 [145]; 153–195 [150]; 227–282 [250]; 315–415.

Thorax. Antepronotum with 12–19 [17] lateral setae; humerals 14 (1); acrostichals biserials between vittae, diverging as uni to multiserial, merging with the dorsocentrals in the prescutelar area; dorsocentrals 44 (1); prealars 26–38 [35]; supraalar 1; anepisternals 0–3 [3]; scutellars 35–86 [76]; postnotum with 0–10 [0]; preepisternals absent.

Wing with macrotrichia in all cells except to r1 and r2+3; length 3.10–3.80 [3.30] mm; width 0.90–1.06 [0.93] mm. L / W = 3.26–4.12 [3.55]. VR 0.88–0.97 [0.94]. C extended beyond R4+5. Brachiolum with 4–8 distal setae, plus 4–5 proximal setae. Squama fringed with up to 65 setae.

Legs. Tibial spur on p1 with slightly curved apex, 102–116 [113] long; comb on p1 with 9–13 [10] short spines ( Fig. 3 ). Tibial spurs on p2 95–120 [115] and 63–83 [75] long ( Fig. 4 ). Tibial spurs on p3 91–120 [113] and 69–81 [75] long ( Fig. 5 ); spur ratio 0.65–0.74 [0.66]; comb on p3 with 10–12 [12] spines, the outer slightly "S" curved ( Fig. 6 ). Two pseudospurs on ta1–2 of p2 and ta1 of p3. Lengths and proportions of legs in Table 3.

fe ti ta1 ta2 ta3 p1 1307–1563 [1540] 1652–1880 [1750] 1224–1351 [1200] 625–717 [625] 415–497 [463] p2 1452–1629 [1588] 1593–1805 [1750] 1017–1152 [1063] 525–612 [525] 350–418 [350] p3 1245–1468 [1325] 1780–2095 [2000] 1328–1544 [1413] 665–795 [725] 428–530 [475]

continued.

ta4 ta5 LR BV SV p1 259–327 [275] 172–226 [200] 0.68–0.76 [0.69] 2.65–2.93 [2.87] 2.38–2.74 [2.74] p2 208–249 [225] 165–200 [200] 0.60–0.66 [0.61] 3.13–3.39 [3.39] 2.91–3.17 [3.14] p3 268–324 [288] 180–207 [200] 0.68–0.76 [0.71] 2.59–2.96 [2.81] 2.27–2.52 [2.35] Hypopygium ( Fig. 7 ). Setae on tergite IX, 17–24. Gonocoxite 249–291 [280] long. Gonostylus 135–161 [145] long. Aberrant specimens (3) with a very thick megaseta-like lateral to the megaseta; 1 aberrant specimen with the very thick megaseta-like, plus 1 additional strong spine ( Fig. 8 ). HR 1.65–2.04 [1.93]; HV 1.97–2.41.

Female (n = 5–7, except when otherwise stated) ( Figs. 9–11 )

Total length 4.50–5.15 (4). Total length / wing length 1.27–1.44 (4).

Coloration: Thorax and wing spots as in male; cercus yelowish.

Head. Antenna with 14 flagellomeres, AR 0.21–0.23 (4). Temporal setae multiserial, 74 (1), postorbitals bi to multiserial, 45 (1). Clypeus with 16–21 setae. Palpomere lengths (I–V) 70–90; 102–150; 150–200; 220–303; 210 (1) long.

Thorax. Antepronotum with 15–26 lateral setae and 0–4 dorsal setae. Acrostichals as in male; prealars 33–55; supraalar 1; anepisternals 1–6 (4), scutelars 86–118. Preepisternals and postnotals absent.

Wing with macrotrichia in all cells except to r1 and r2+3; length 3.40–3.70 mm; width 1.16–1.50 mm; L / W = 2.39–2.90. VR 0.92–0.97. C extended beyond R4+5. Squama fringed with 60–87 setae. Macrotrichia above dark spots thick and densely grouped

Legs. Tibial spur on p1 95–120 long; on p2 93–128 and 66–88 long; on p3 93–120 and 73–83 long. Spur ratio on p3 0.65–0.78. Comb on p3 with 9–12 spines; no tibial comb on p1. Two pseudospurs on ta1–3 of p2 and ta1 of p3. Lengths and proportions of legs in Table 4 .

Genitalia ( Fig. 9 ). Cercus 81–125 long. Seminal capsule 91–125 long ( Fig. 10 ); notum 216–300 long (2); tergite IX with 0–5 setae (3) ( Fig. 11 ); segment X with 6–13 setae (4).

Pupa (n = 4–9, except when otherwise stated) (Figs. 12–17)

Total length 6.25–8.30 mm.

Cephalothorax (Fig. 12). Frontal apotome as in Fig. 13. Thoracic horn (Fig. 14) arising from a distinct tubercle; external membrane with spines; respiratory atrium almost straight. Length 524–596; width 106–135; L / W 4.41– 4.95; plastron plate 58–85 long; 97–132 wide; plastron plate length / thoracic horn length 0.11–0.15. Thoracic setation (Fig. 15): DC1 41–54; DC3 95–140; Sa 203 long (1); MAps 175–188 long (2).

Abdomen. Scar on segment I, 216–249 long. Shagreen with single spines. Chaetotaxy (Figs. 16, 17): D1 more or less straight, arising from a distinct tubercle on segments I–VII. D1 is situated in the same line or slightly posteriorly to D 2 in segments VI and VII. D2 and D4 longer than D1, arising from a distinct tubercle in segments II–VII. D3 and D5 short and thin, arising from a very short tubercle or tubercle absent. Segments I–VI with two pairs of FIGURES 12–26. Alotanypus vittigera (Edwards) comb. nov. immatures. Pupa: 12, cephalothorax; 13, frontal apotome; 14, thoracic horn; 15, thoracic setae: Dc1, Dc2 and Sa from left to right; 16, complete abdominal setation; 17, tergite and sternite of abdominal IV segment. Fourth-instar larva: 18, ventral cephalic setation; 19, dorsal cephalic setation; 20, antennite I; 21, apex of antenna; 22, mandible; 23, ligula; 24, dorsomental teeth; 25, procercus; 26, simple claws of posterior parapod. Scale bars = 20 μm for Fig. 21; 50 μm for Figs. 13, 24, 26; 100 μm for Figs. 12, 15, 20, 22, 23, 25; 200 μm for Figs. 14, 17; 500 μm for Fig. 16.

short lateral setae. Segments VII and VIII with 5; anal lobe with 2 pairs of long and teniated lateral setae. Position of LS1 / segment length = 0.45–0.51 on segment VII; 0.22–0.27 on segment VIII. Anal lobe 803–996 long; 400– 450 wide; L / W 1.93–2.05. Position of LS / anal lobe length 0.16–0.18 for LS1 and 0.27–0.28 for LS2.

Male genital sac 355–387 long; length of male genital sac / length of anal lobe 0.42–0.44.

Fourth-instar larva (n = 5–6, except when otherwise stated) (Figs. 18–26)

Total length 0.77–0.91 mm (2). Head: capsule 620–800; 820–1000 wide. CI 0.76–0.85.

Cephalic setation: Ventral (Fig. 18): SSm between S9 and S10;SSm close to S10 and VP posterior to S10. Dorsal (Fig. 19): S7, S8 and DP arranged in a line; S6 anterolateraly to S7.

Antenna (Figs. 20, 21). AR 4.9–5.6; A1 233–266 long, ring organ situated at 0.70–0.76 from base; BL1 35–42 long; NB 33–37 long; NB / BL1 0.83–0.90; BL1 / A2–4 0.80–0.88; A 2 28–35 long, length A2 / width A2 4.3–6.6 (3); BL 2 10–11; A 3 7–11 long; length A3 / width A3 3.6–4.4; A4 5 long.

Maxillary palp: basal segment 60–73 long, length / basal width 0.59–0.67; relative distance of CS 0.59–0.67. A1 / PMx 3.64–4.08. Mandible (Fig. 22) 191–213 long. A1 / Mn 1.17–1.26. Hypopharingeal complex: Ligula 108– 145 long (Fig. 23), the outermost inner teeth slightly outcurved; paraligula bifid, 60–95 long; pecten hypopharyngis with 14–18 teeth; dorsomental teeth 5–7 (Fig. 24).

Abdomen. Procercus 250–350 long (Fig. 25); L / W 3.00–3.50; with 13 setae 855–1050 long. Preanal seta 780– 830 long. Posterior parapods: smallest claws simple curved (Fig. 26).

Biology. The species A. vittigera was found in a wide range of standing water environments such as lakes, temporary pools and “mallines” (singular “mallín”). A “mallin” can be characterized as a humid meadow with a dense cover mainly dominated by Juncaceae , Cyperaceae and Gramineae . The mallín soil contains a high percentage of organic matter and always associated with either surface water or ground water discharge. This kind of wetland in the Andes mountains is characterized by harsh environmental conditions, as the plant growth season is relatively short (abouth 4 months) and snow cover remains for about 6 months during the year ( Raffaele 1996).

Cladistic analysis. The data set analyzed under K = 5 to 16 yielded the same tree topology ( Fig. 27 ) in each of the concavities (CI = 0.47, RI = 0.42). The tree derived from K = 5 (score = 30.37) showed the best character measure support calculated as absolute frequencies, frequency differences and absolute Bremer support. The best relative Bremer support measures were those of K = 7 (score = 29.7).

The genus Alotanypus is a monophyletic group supported by the synapomorphies male AR of 1.8, male LR III of 0.68–0.76, female wing length of 3.30–4.20 mm, L / W of thoracic horn 3.00–4.60, relative position of LS1 on segment VII of 0.51, relative position of LS1 on segment VIII of 0.23–0.31, CI of 0.83–0.84, postnotal setae absent, tibial comb I present, claws spatulate (at least on pII). Alotanypus venustus is the basal species of the genus followed by A. dalyupensis and A. aris . The species A. vittigera is closely related with A. kuroberobustus and shares the characters male AR of 1.90–2.10, male wing length of 3.10–3.80, male LR II of 0.60–0.66, female LR II of 0.53–0.61, L / W of thoracic horn of 4.30–5.50, relative position of LS1 on segment VII of 0.45–0.51, NB / BL1 of 0.77 and curved apex of spur I on male.

The clade [ A. aris - A. vittigera - A. kuroberobustus ] shares the characters female LR III of 0.63–0.71, DC1 of 54– 58 um long, thoracic horn of 524–680 um long, larval AR of 5.30–6.40, BL1 / A2–4 of 0.80–0.88, A1 / Ring 0 of 0.70–0.76 and L / W PMx of 2.75–3.30.

The clade [ A. dalyupensis - A. aris - A. vittigera - A. kuroberobustus ] shares the characters DC1 of 78 um long, plastron plate / thoracic horn of 0.15–0.33, L / W of anal lobe of 1.82, L / W of A2 of 4.50, relative position of CS on PMx of 0.50, mandible of 191–220 um long, A1 / mandible of 1.19–1.29 and procercus of 296 um long.

Guassutanypus oliveirai is the sister group of Alotanypus . This clade shares the presence of preepisternals, RM, FCu and MCu darkened veins on male and female, assymetrical neck position on seminal capsules, relative position of LS1 on abdominal segment VII, horn sac of the thoracic horn not filling the entire horn lumen, number of teniated setae on segment VIII on pupa. This last clade is the sister group of the clade [P. d y a r i -D. alaskensis] by sharing characters: LR I on male; FCu vein darkened in male and female; length of DC3 on pupa, A1 / PMx, pecten hypopharnix and number of setae on procercus.

The tribe Macropelopiini is monophyletic and it is supported by the synapomorphies male wing length of 3.00, male spur ratio of 0.28–0.42, female anal lobe length of 695–864, genital sac / anal lobe of 0.36–0.42, relative position of 0.16–0.17 for LS1 and 0.25–0.26 for LS2 on anal lobe, larval AR of 6.05–7.00, L / W PMx of 2.70, procercus length of 163–222, postorbitals multiserials, male spur thorn like. Spur teeth bigger than 15, outer fringed on anal lobe present and teniata setae on abdominal segment VII bigger than 5.

Figures

FIGURE 1. Alotanypus vittigera (Edwards) comb. nov. Male: abdomen in dorsal view. Scale bar = 500 μm.

FIGURES 2 – 11. Alotanypus vittigera (Edwards) comb. nov. adults. Male: 2, wing; 3, tibial spur and comb on fore leg; 4, tibial spurs on mid leg; 5, tibial spurs on hind leg; 6, tibial comb on hind leg; 7, Hypopygium, dorsal view to the left and ventral view to the right; 8, apex of gonostylus of two aberrant form. Female: 9, genitalia; 10, detail of seminal capsule and the first portion of the duct; 11, abdominal setation of tergite IX. Scale bars = 50 μm for Figs. 3 – 6, 8; 100 μm for Figs. 7, 9 – 11; 200 μm for Fig. 2.

FIGURE 27 (part I). Cladogram obtained under K 5. Synapomorphies are in bold. Numbers below nodes represent, from left to right, the support as Frequency Differences, as Absolute Differences, the Bremer support and the Relative Bremer Support respectively (unavailable data scored as " - ").

Tables

TABLE 4. Lengths (μm) and proportions of legs of Alotanypus vittigera comb. nov., female (n = 5 – 7).

fe p1 1370–1700 p2 1525–1900 p3 1287–1625	ti 1680–2100 1660–2025 1836–2375	ta1 1121–1325 934–1100 1183–1500	ta2 564–700 477–600 633–800	ta3 405–488 332–425 436–550
continued.
ta4 p1 250–325 p2 208–250 p3 270–325	ta5 200–250 166–208 200–228	LR 0.61–0.67 0.53–0.59 0.61–0.68	BV 2.74–2.98 3.23–3.48 2.65–2.89	SV 2.64–2.96 3.15–3.65 2.43–2.73