Cryptotendipes emorsus (Townes)

Saether, Ole A., 2010, Cryptotendipes Lenz from Manitoba, Canada, with keys to known immatures of the genus (Diptera: Chironomidae), Zootaxa 2412, pp. 1-20 : 8-10

Cryptotendipes emorsus (Townes)

Harnischia emorsa Townes, 1945: 161 . ( Fig. 4 )

Material examined. CANADA: Manitoba, South Indian Lake, Trailer Bay and Long Bay, male (intersex caused by infection) reared from larva, 3 pupae reared from larvae, 2–10.vii. 1976, E. Phillips; Manitoba, Heming Lake, female reared from larva, Man., 27.vii 1967, A.P. Wiens. Lake Winnipeg records: Beaver Creek, 7.vi. –24.vii. 1971, male with thorax and 3 first abdominal segments of pupal exuviae, 4 males.

The male imagines have 3–7, 5 (4) setae on squama; 3–10, 6(4) sensilla chaetica 16 on p2 and none on p3. The hypopygium is illustrated by Saether (1977a fig. 34A). A male reared from larva, as well as mature male and female pupae have been found in South Indian Lake, Man. A female reared from larva from Heming Lake, Man., appears to be C. emorsus although it differs in having longer thoracic horn and caudal spines also on T VIII.

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

All measurements and ratios completely within the range of female C. tuberosus with the following exceptions: Wing length 1.32 mm. Total length/wing length 1.87. Wing length/profemur 2.87.

Head. Ultimate palpal segment apparently about 88 µm.

Thorax. Antepronotum with 4 setae. Acrostichals 3.

Wing. VR 1.21.

Legs. LR1-3, as 1.67, 0.45, 0.61. BV1-3 2.19, 3.63, x.86. SV1-3 1.43, 4.56, 3.40.

Genitalia. Gonocoxite IX with 2(2) setae. Notum 90–100 µm (2) long. Seminal capsule 60-62 µm (2) long, 44 µm (2) wide. Genitalia mounted in lateral view on complete specimen.

Pupa (n = 4–6, except when otherwise stated)

Total length 2.52–3.41, 3.04 mm.

Cephalothorax. Cephalic tubercle 30–52, 43 µm high; 21–38, 28 µm, wide; with 33–52, 42 µm long frontal seta. Thoracic horn 1.48-3.65, 2.32 mm long, (3.65 mm in pupa from Heming Lake, Fig.4 C); main stem 0.59–1.93, 1.05 mm long, (1.93 mm in pupa from Heming Lake, 0.59–1.22 in remaining pupae).

Abdomen ( Fig. 4 A, B). Shagreen and chaetotaxy as illustrated. Caudal margin of T II with 6–14, 8 hooklets (14 in pupa from Heming Lake, 6–7 in others). Numbers of caudal spines on T II–VIII: 6––16, 11; 10–16, 14; 13–17, 15; 16–22, 19; 22–32, 26; 0–12, 8; 0–6, 2. Lengths of caudal spines on T II–VIII (in µm): 4––10, 8; 3–24, 16; 12–32, 21; 20–32, 25; 16–26, 22; 16–20 (3); 0–4 (3). S I with groups of 10–16, 13 µm, long spinules. Numbers of caudal spines on S II–VII: 0–10, 3; 2–6, 5; 5–10, 8; 4–5, 4; 0–12, 5; 0–6, 2. Lengths of caudal spines on S II–VII (in µm): 0–12, 5; 4–10, 8; 6–12, 11; 4–14, 10; 0–12, 6; 0–8, 4. VIII with 100–116, 108 µm long spur; 12–30, 18 µm wide at base; located 50–52 µm (2) anterior of caudolateral corner. Segments V–VIII each with 4 taeniate L-setae. Anal lobe with 17–31, 21 taeniae in fringe; apical 9–14, 11 wider and darker than basal ones, (31 taeniae in pupa from Heming Lake, 17–20 in others).

Fourth instar larva (n = 4–5, except when otherwise stated)

Head capsule length 0.25–0.28 mm. Head capsule brownish yellow with about 130–174, 149 µm wide, 55-–76, 61µm long brownish black ventral spot.

Head. Antenna as in Fig. 4 D. Lengths of antennal segments (in µm): 34–40, 37; 10–13, 11; 4–7, 5; 5–7, 6; 5–6, 5. AR 1.13–1.31, 1.23. Basal antennal segment 13–16, 14 µm wide; ring organ 9–12μm from base; blade 20 µm (1) long; accessory blade 16 µm (1) long. Labrum with S I 23–30, 26 µm long; S II 32 –36, 34µm long. Premandible 66–73, 69 µm long. Mandible 100–111, 105 µm long. Median tooth of mentum ( Fig. 4 E) not including lateral notches 19–24, 22 µm wide; including notches 36–40, 38µm wide. Ventromental plates 74– 82, 77 µm wide; 30–36, 32 µm long; 2.28–47, 2.38 times as wide as long. Postmentum 120–130, 125 µm long; 128–130 µm (2) 21 long in males; 120–126 µm (3) in females.

Abdomen. At least some abdominal segments with small caudolateral tufts of setae. Procercus 21–24, 23 µm high; 20–25, 22 µm wide; with 500–601, 529 µm long anal setae. Supraanal seta 276–330, 307 µm long; supraanal seta/anal setae 0.46–0.66, 0.59. Anal tubules 68–100, 78 µm long; 36–40, 37 µm wide at base. Posterior parapods 154–170,164 µm long.

Remarks. The female from Heming Lake may represent another species. However, only some details of the pupa differ while the larva appears to be identical with those from other localities.

Distribution and ecology. The species was previously known from Manitoba, Québec, New York, New Jersey, District of Columbia, South Dakota, Kansas, Iowa, Ohio, Kentucky, North Carolina and south to Florida ( Townes 1945: 161, Oliver et al. 1990: 44, Epler 2009). Johannsen (1937: 44) found the species, as Chironomus (Limnochironomus) sp. in Beebe Lake, near Ithaca, New York.

Figures

FIGURE 4. Cryptotendipes emorsus (Townes), immatures. A – pupal tergites; B – pupal sternites; C – whole pupa showing size of thoracic horn; D – antenna of larva; E – mentum.