Ablabesmyia (Ablabesmyia) basalis (Walley)

Saether, Ole A., 2011, Notes on Canadian Ablabesmyia Johannsen, with keys to known Nearctic immatures of the genus (Diptera: Chironomidae), Zootaxa 3069, pp. 43-62 : 57

publication ID	https://doi.org/ 10.5281/zenodo.279010
DOI	https://doi.org/10.5281/zenodo.5679775
persistent identifier	https://treatment.plazi.org/id/03B287EE-FFE0-FFBC-FF48-5FD7365FF9A3
treatment provided by	Plazi
scientific name	Ablabesmyia (Ablabesmyia) basalis (Walley)
status

Treatment

Ablabesmyia (Ablabesmyia) basalis (Walley) View in CoL

( Figs 2 View FIGURE 2 E; 3 E; 4 E, L; 5 F; 8 D–F)

Ablabesmyia (Ablabesmyia) basalis (Walley) View in CoL ; Roback 1971: 373.

Ablabesmyia (Ablabesmyia) monilis Roback, 1985:185 View in CoL nec (L.), pro parte.

Material examined. CANADA: Manitoba, Rat River south of Woodridge, silt, 0.1–0.2 m, 2 males reared from larva, 23.vi. 1967, A. L. Hamilton, B. Hauser and O. A. Saether. Lake Winnipeg records: Pine Dock, 2 males, 10.vii. 1969; Gull Harbour, 1 male, 16.vii. 1969; 3 km off George Island, 1 male, 27.vii. 1969; 20 Mile Creek, 1 male, 1.ix. 1971; Old Fishing Dock, 5 males, 11.viii. 1971; Calder's Dock, 4 males, 30.viii. 1971. Ontario, Rushing River Campsite, 4 females, 22. viii. 1972, A. L. Hamilton and O. A. Saether.

A few male imagines illustrated in Fig. 8 View FIGURE 8 D–F were collected from the light traps. The immatures of three males reared from larvae and pupae are described below. As mentioned by Roback (1971: 372–373) the pupa described by Hauber (1945: 498) does not belong to A. basalis , but to A. (A.) rhamphe Sublette. Roback (1985: 185) having some doubt synonymized A. (A.) basalis with A. (A.) monilis . As the present material show differences in all stages A. (A.) basalis is here retained as a valid species.

Pupa (n = 3). Total length 4.38–4.73 mm. Exuviae dark, grayish brown.

Cephalothorax. Wing sheath mostly uniformly pigmented with irregular clear maculae distributed near the margins, cross vein distinctly darkened, surrounded by a clear area, no indication of a vein pattern; cephalothorax mostly clear. Thoracic horn ( Fig. 2 View FIGURE 2 E) 374–454 µm long, 153–221 µm wide, 2.42–2.64 times as long as wide; respiratory duct ( Fig. 2 View FIGURE 2 E) slightly S-shaped with club-shaped apex. Thoracic comb ( Fig. 2 View FIGURE 2 E) consisting of 10–13 longer and a few minute spines, longest spines 50–61 µm.

Abdomen. Abdominal segments II–V with pale anterior margins, conjunctives laterally with distinct brown spot. Anal lobe ( Fig. 3 View FIGURE 3 E) 1.06–1.19 times as long as wide, outer margin distad of distal seta with 6–9 spinules.

Fourth instar larva (n = 1–2). Head capsule length 0.77–0.80 mm.

Head. Head capsule with two ventromesal dark spots larger one closer to the middle, the other smaller near the posterior margin. Antenna as in Fig. 4 View FIGURE 4 E. Lengths of antennal segments (in µm): 313–325, 61, 8, 4. AR 4.34. Basal antennal segment 24–26 µm wide, ring organ 0.61–0.63 from base, blade 65 µm long. Mandible 131–134 µm long. Maxillary palp ( Fig. 5 View FIGURE 5 F) 3-segmented; lengths of segments (in µm): 10–12, 32–37, 37–40; widths of segments: 18, 12–13, 8–9. Ligula ( Fig. 4 View FIGURE 4 L) 96–100 µm long, with inner teeth outcurved ( Fig. 4 View FIGURE 4 L). Paraglossa 42–46 µm long. Hypopharyngeal pecten with 20 teeth.

Abdomen. Procercus 108–112 µm high, 34–40 µm wide, 2.80–3.18 times as high as wide. Anal setae 490 µm long, supraanal seta 334–336 µm long, supraanal seta/anal setae 0.68. Posterior parapods about 675 µm long, with 1 dark claw, with sharply bent claw.

Remarks. The differences between the immatures mentioned in the keys are based on the present material and possibly may not all hold on a larger material. The spots on the larval head capsule are about as distinct as in A. (A.) simpsoni , however, the posterior parapod has a sharply bent claw. In the imagines the abdominal tergites II–V are clear and suffused with brown, the lateral bulge of gonocoxite very strong and the blade considerable more stout than in A. (A.) monilis auct ., all in accordance with Roback (1971).

Distribution. The species is known from Québec and New Jersey to British Columbia, Washington and Alaska ( Roback 1971: 374, 1984: 22). In Lake Winnipeg the few adults were caught in the central and northern parts.