Cryptotendipes tuberosus, Saether, Ole A., 2010

Saether, Ole A., 2010, Cryptotendipes Lenz from Manitoba, Canada, with keys to known immatures of the genus (Diptera: Chironomidae), Zootaxa 2412, pp. 1-20 : 4-8

Cryptotendipes tuberosus sp. n.

( Figs 2 , 3 )

Cryptotendipes sp. A, Rosenberg et al. 1984: 673.

Type material. Holotype male reared from larva, CANADA: Manitoba, South Indian Lake, Trailer Bay, depth 1 m, 13.vi.1976, E. Phillips ( CNC). Allotype: female reared from larva, as holotype. Paratypes: 3 males reared from 5 larvae, 2 females reared from larvae, 2 mature female pupae reared from larvae, 1 male pupal exuviae, Long Bay and Trailer Bay, 8-18.vi. 1976, otherwise as holotype.

Diagnostic characters. The male imago is characterized by an AR of 1.74–1.86, 2–4 antepronotal setae, 19 on squama, T IX with high hump or ridge, inner margin of gonostylus with a median projection forming a distinct concavity in apical half, and anal point about as long as superior volsella.

The female has 0–1 seta on gonocoxite IX, 17–24 setae on T IX, 4–7 sensilla chaetica on each of p2 and p3, 5– 7 setae on squama and 19–25 setae on R4+5.

The pupa has 2 long, spine-covered tubercles caudally on each of T II–VII, and one long, bi-trifid tubercle with apical spines on S III–VIII; and is lacking a caudolateral spur on VIII.

The larva has a 126–146 µm long postmentum, and AR of 1.26–1.75, the median mental tooth not including lateral notches is 20–24 µm wide and more or less rounded, the ventromental plates are 1.67–1.95 times as wide as long, and the basal antennal segment is 42–50 µm long.

Description. Male imago (n = 4, except when otherwise stated)

Total length 3.06–3.19, 3.10 mm. Wing length 1.60–1.68, 1.66mm. Total length/wing length 1.83–1.91, 1.87. Wing length/profemur 2.68–2.72, 2.70. Coloration pale brownish with darker vittae, postnotum, preepisternum, and part of anepisternum. Haltere pale.

Head. AR 1.74–1.86, 1.80. Temporals 10–11, 11. Clypeus with 9–15, 12 setae. Cibarial pump, tentorium and stipes as in Fig. 2 A. Tentorium 117–130, 127 µm long. Stipes 118–139, 132 µm long. Palp lengths (in µm): 33–36, 35; 37–46, 42; 71–86, 82; 104–109, 105; 122–142, 132.

Thorax. Antepronotum with 2–4, 3 setae. Dorsocentrals 6–7, 6; acrostichals 5–8, 6; prealars 3–4, 4; supraalar 1. Scutellum with 8–9, 9 setae.

Wing. VR 1.18–1.20(3). Brachiolum with 2–3, 2 setae; R with 3–5, 4; R1 with 0–1, 0; R4+5 with 2 apical setae. Squama with 2–4, 3 setae.

Legs. Sensilla chaetica 2–5, 3 on p2; none on p3. Lengths and proportions of legs as in Table 1.

fe ti ta1 ta2 ta3 ta4

p1 589–626, 614 399–442, 423 662–692, 679 380–429, 412 265–307, 289 172–178, 174

p2 552–601, 584 521–540, 532 239–270, 256 165–184, 176 123–147, 134 80–86, 83

p3 687–736, 715 638–687, 664 405–478, 437 276–301, 285 221–251, 238 110-123, 118 ta5 LR BV SV BR

p1 86–104, 95 1.56–1.64, 1.60 1.72–1.82, 1.77 1.50–1.55, 1.53 2.6–3.0 (2)

p2 63–67, 65 0.45–0.50, 0.48 2.95–3.07, 3.01 4.23–4.64, 4.34 3.1–4.1 (2)

p3 76 0.62–0.70, 0.66 2.97–3.32, 3.16 – 3.0–3.3, 3.2

Hypopygium ( Fig. 2 B). T IX with 16–19, 17 setae; 5–6, 6 of them ventrally; laterosternites IX each with 2–4, 3 setae. Phallapodeme 74–82, 78µm long. Transverse sternapodeme 29–34 µm (3) long. gonocoxite 90– 100, 97 µm long; Gonostylus 146–152, 149 µm long. HR 0.62–0.68, 0.65; HV 2.01–2.16, 2.09.

Female imago (n = 3, except when otherwise stated).

Total length 2.34–2.51 mm. Wing length 1.34–1.58 mm. Total length/wing length 1.59–.74. Wing length/ profemur 2.99–3.17.

Head. AR 0.40-0.55. Flagellomeres length (in µm): 71–76, 40–44, 39–41, 46–50, 85–110. Temporals 8– 10. Clypeus with 10–16 setae. Cibarial pump, tentorium and stipes as in Fig. 2 C. Tentorium 90–1091, 122 μm long. Stipes 130–140 μm along. Palp lengths (in µm): 30–32, 31–39, 23 68–72, 84–89, 104–140.

Thorax. Antepronotum with 2–3 setae. Dorsocentrals 10–12, acrostichals 5–6, prealars 2–3, supraalar 1. Scutellum with 9 setae.

Wing. VR 1.23–1.25 (2). Brachiolum with 2 setae, R with 10-15, R1 with 7–9, R4+5 with 19–25 setae. Squama with 5–7 setae.

Legs. Sensilla chaetica 6–7 on p2, 4-6 on p3. Lengths and proportions of legs as in Table 2.

Genitalia ( Fig. 2 D, E). Cercus 70–86 µm long. gonocoxite IX with 0–1 seta. T IX with 17–24 setae. Segment X bare as in other Cryptotendipes . Ventrolateral lobe with relatively distinct group shagreen, about as wide at apex as dorsomesal lobe ( Fig. 2 E). Apodeme lobe with indication of basally branched apodeme. Coxosternapodeme strong, heavily sclerotized with sharp anterior angle. Notum 114–134 µm long. Seminal capsule 54–60 µm long, 46–48 µm wide.

fe ti ta1 ta2 ta3 ta4

p1 448–497 307–350 497–552 245–264 172–190 110–117

p2 380–491 380–466 159–202 98–129 86–98 55–63

p3 503–577 485–540 307–331 196–209 153–178 76–86 ta5 LR BV SV BR

p1 67–80 1.57–1.62 2.08–2.14 1.48–1.59 2.5 (1)

p2 49–55 0.42–0.43 3.19–3.38 4.73–4.78 2.1–2.4 (2)

p3 63–67 0.60–0.63 2.67–2.74 3.22–3.48 –

Pupa (n = 9, except when otherwise stated)

Total length 3.34–4.02, 3.66 mm; 3.84–4.02, 3.75 mm (4) in males; 3.19–3.67, 3.44 mm (5) in females.

Cephalothorax. Cephalic tubercles 44–68, 54 µm high; 36–50, 41 µm wide; with 35–58, 51 µm (7) long frontal seta. Thoracic horn 2.27–3.88, 2.99 mm (8) long; main stem 0.96–1.49, 1.25 mm long.

Abdomen ( Fig. 3 A–D). Shagreen and chaetotaxy as in Fig. 3 A, B. Caudal margin of T II without hooklets. T II and VII each with 2 caudal tubercles 36-84, 61 µm high; each tubercle with 2–8, 5 apical spines. T III–VI each with 2 caudal tubercles ( Fig. 3 C) 60–150, 102 µm high; each tubercle with 3–12, 7 apical spines. S I with anterior groups of 0–34, 16 µm (5) long spinules; S II with groups of 4–26, 18 µm (8) long spinules; S III–V each with one bi-trifid 80–115, 113 µm long tubercle ( Fig. 3 D) with 4-14, 9 apical spines. S VI and VII each with 40–110, 74 µm long tubercle with 3-10, 7 apical spines. S VIII of male with one 38–60, 45 µm (4) long tubercle with 7-16, 10(4) apical spines. Caudolateral margin of segment VIII apparently bare. Segments V-VIII each with 4 taeniae. Genital sac of anal lobe over-reaches anal lobe by 70–90 µm (3) in male; 4–14?, 9µm (5) in female. Anal lobe with 22–30, 25(7) taeniae in fringe; apical 8–18, 15 (7) wider and darker than 8– 25, 10 (7) basal ones.

Fourth instar larva (n = 8–9, except when otherwise stated)

Total length about 2.8–3.0 mm (3). Head capsule length 0.23–0.28, 0.26 mm. Head capsule brownish yellow with about 160–190, 175 µm wide, 62–80, 72 µm long brownish black ventral spot.

Head. Antenna as in Fig. 3 E. Lengths of antennal segments (in µm): 42–50, 44; 9–13, 12; 4–6, 5; 6–8, 7; 4–6, 5. AR 1.26–1.75, 1.44 [1.26–1.35, 1.30 (4) in males; 1.40–1.75, 1.58 (4) in females]. Basal antennal segment 14–16, 15µm wide; ring organ 12–20, 15 µm from base; Blade 20–24, 21µm (5); accessory blade 16 µm (1) long. Preapical style of second segment 7–9, 8µm (6) long. Labrum ( Fig. 3 F) with S I 24–33, 27 µm (4) long; S II 34 –40 µm (3) long. Premandible 65–82, 70 µm long. Mandible 90–118, 100 µm long. Median tooth of mentum not including lateral notches or accessory teeth 20–24, 22 µm wide; including notches 36– 42, 38 µm wide ( Fig. 3 G). Ventromental plates 70–81, 76 µm wide; 39–48, 42 µm long; 1.67–1.95, 1.81 times as wide as long. Postmentum 126–146, 136 µm long.

Abdomen. At least some abdominal segments with small caudolateral tufts of setae. Procercus 20–28, 24 µm high; 19–28, 24 µm wide; with 440–510, 466 µm (7) long anal setae. Supraanal seta 205–300; 249 µm; supraanal seta /anal setae 0.47–0.63, 0.54 (7). Anal tubules 78–91, 83 µm long; 30–50, 42 µm wide at base. Posterior parapods 150–190, 174 µm long.

Remarks. The male imago will key out near Cryptotendipes nigronitens (Edwards) in Saether (1977a: 97) from which it differs by having a lower AR [1.74–1.86 as opposed to about 3 in C. nigronitens according to Edwards (1929: 390)]. The female imago is easily separable from those keyed in Saether (1977b: 171). The coxosternapodeme is most similar to C. pseudotener , the apodeme lobe somewhat in between C. pseudotener and C. darbyi , while the lobes of gonapophysis VIII appear most similar to C. casuarius . The characters of the immatures will appear from the above keys.

Distribution. The species is known only from South Indian Lake, Man.

Figures

FIGURE 2. Cryptotendipes tuberosus sp. n., imagines. A – cibarial pump, tentorium and stipes of male; B – male hypopygium; C – cibarial pump, tentorium and stipes of female; D – female genitalia; E – gonapophyses of female genitalia (DmL = dorsomesal lobe, VlL = ventrolateral lobe, ApL = apodeme lobe).

FIGURE 3. Cryptotendipes tuberosus sp. n., immatures. A – pupal tergites; B – pupal sternites; C – caudal tubercles of tergites; D – caudal tubercles of sternites E – larval antenna; F – labrum and epipharynx; G – mentum.