Doncricotopus nunavummiuti, Namayandeh & Beresford, 2021

Namayandeh, Armin & Beresford, David V., 2021, Review of the genus Doncricotopus (Orthocladiinae: Chironomidae): with the description of a new species from Canada, Journal of Natural History 55 (19 - 20), pp. 1195-1211 : 1199-1206

Doncricotopus nunavummiuti sp. n.

LSID: urn:lsid:zoobank.org:act:BE3BD776-E33A-457F-BE42-65B6A77DA7CF ( Figures 2 (a-d), 3(a-c), 4(a-g), 5(a-e), 6(a-f), 7(a))

Type material. Holotype: one male reared from larva, Canada, Nunavut, Hazen Camp , 81° 49 ʹ N, 71° 18 ʹ W, 17.VII. 1965, leg. D. R. Oliver, No. CH1208, CNC . Paratypes: one male read from larva, Canada, Nunavut, Hazen Camp , 81° 49 ʹ N, 71° 18 ʹ W, 1963, leg . D. R. Oliver , No . CH1213, CNC; 1 male, Canada, Nunavut, Hazen Camp , 81° 49 ʹ N, 71° 18 ʹ W, 17 . VII.1963, leg . P .S . Corbet , No . CH1221, CNC; one male, Canada, Nunavut, Hazen Camp , 81° 49 ʹ N, 71° 18 ʹ W, 29 . VII. 1961, leg. D. R. Oliver , No . CH3760, CNC; one male read from larva, Canada, Nunavut, Hazen Camp , 81° 49 ʹ N, 71° 18 ʹ W, 1963, leg . D. R. Oliver , No . CH 1206, CNC

Additional materials. 1 female reared from larvae, Canada, Nunavut, Hazen Camp , 81° 49 ʹ N, 71° 18 ʹ W, 19 . VII.1965, leg. D. R. Oliver, No . CH1207; one female reared from larvae, Canada, Nunavut, Hazen Camp , 81° 49 ʹ N, 71° 18 ʹ W, 1963, leg . D. R. Oliver, No . CH 1211, CNC; 1 female read from larvae, Canada, Nunavut, Hazen Camp, 81° 49 ʹ N, 71° 18 ʹ W, VI .1965, leg . I . Mc Alpine & D . R. Oliver, No CH1222, CNC; one male puparium reared from larva, Canada, Nunavut, Hazen Camp , 81° 49 ʹ N, 71° 18 ʹ W, 1963, leg . D. R. Oliver, No . CH 1212, CNC; 1 male puparium reared from larva, Canada, Nunavut, Hazen Camp , 81° 49 ʹ N, 71° 18 ʹ W, 15 . VII.1963, leg. D. R. Oliver, No . CH 1206, CNC; 1 pupa, Canada, Nunavut, Hazen Camp , 81° 49 ʹ N, 71° 18 ʹ W, 23 . VII.1963, leg. D. R. Oliver, No . CH 1209, CNC .

Etymology. An Inuktitut word, ‘ nunavummiuti ’ means people inhabiting Nunavut. Named in honor of the Nunavut territory and its people the Inuit.

Diagnostic characters. Male: AR 1.4–1.6, 1.5. Dorsocentrals 12–14, acrostichals 3. R vein with 6–9 setae, squama with 14–17 setae. Superior volsella developed and round. Inferior volsella nearly squared, basally flat. Sternapodeme a broad band, nearly straight. Anal point 36–43, 41 μm long. Gonostylus racquet-shaped with anterior edge quadrate. HR 2.6, HV 3.2. Female: Antenna 5 segmented, AR 2.9– 0.32, 0.31. Tentorium long and narrow. Dorsocentrals 7–10, acrostichals 2. R with 6– 7 and squama with 9–11 setae. Tergite IX with two oval light patches and seven setae. Two circular seminal capsules with necks having loops. Cercus semi-circular, with pediform extensions. Pupa: Frontal setae 188–195, 192 μm long on 25 μm high and 22 μm wide tubercles. Thoracic horn 212–316, 276 μm long, 58–63, 61 μm wide, with rounded apex. Tergites III with few median spines. Anal lobe with 20–24, 22 setae in fringe. Larva: Head capsule dark brown. Blade reaching the tip of fourth segment. Lauterborn organ robust covering the 3rd–4th segments. Mandible with apical tooth subequal to combined length of inner teeth. Mentum with median teeth about 3.8 × the length of first laterals. Ventromental plate’s cardinal beard with six setae. Posterolateral margins of the mentum extend well-beyond the base of ventromental plates. Procercus with two small tubercles and four apical setae.

Description. Male (n = 4).

Size. Total length 3.0–4.0, 3.5 mm. Wing length 2.0–2.5, 2.2 mm, Wing width 0.53–0.57, 0.55 mm.

Coloration of mounted specimens. Head, thorax, abdominal tergites and hypopygium brown. Abdominal sternites, wing and halter light to golden-brown.

Head ( Figure 2 (a-c)). AR 1.4–1.6, 1.5. Ultimate flagellomere 561–611, 587 μm long, apex of ultimate segment diamond shape with flat tip, with 7–9 sensilla clavata; sensilla clavata also on 2nd and 3rd flagellomere ( Figure 2 (b)). Coronal setae 4. Temporal setae 4–5, 4, including 3–4, 3 outer verticals and one frontal. Clypeus 76–99, 87 μm long and 135–141, 138 μm wide, with 16 setae, 60–84, 75 μm long. Tentorium, stipes, and cibarial pump as in Figure 2 (a). Tentorium 166–183, 177 μm long. Palp segment lengths (in μm): 32–50, 38; 51–65, 57; 79–108, 94; 95–112, 104; 160–190, 175. Third palpomere with sensilla coeloconica and two sensilla clavata anterodorsally ( Figure 2 (c))

Thorax ( Figure 2 (d)). Antepronotum with five lateral setae. Dorsocentrals 12–14 in single row; acrostichals apparently 3 in mid-section; prealars 4–5, 4. Scutellum with six setae in single row. Humeral pit small but distinct.

Wing ( Figure 3 (a)). Costa extension 64–90, 76 μm long. Brachiolum with one seta; Squama with 14–17, 16 setae; R with 6–9 setae; other veins and membrane bare. Cu with slight bend at the tip. An about ½ of the Cu.

Legs. Legs. Fore legs with tibial spur 37–56, 48 μm long. Mid tibial spurs 19–23, 21 and 15–18, 17 μm long. Hind tibial spurs 51–60, 54 and 20–23, 22 μm long, hind tibia comb with 24–26 spines. Hind femur with keel. Pulvilli well-developed, almost half as long as the claws. Lengths and proportions of legs as in Table 1.

Hypopygium ( Figure 3 (b-c)). Tergite IX covered with microtrichia; laterosternite IX with 14–17, 16 setae. Anal point bare 36–43 (41) μm long ( Figure 3 (b-c)). Phallapodeme 58–87, 69 μm long, sternapodeme a broad band, nearly straight, 117–141, 129 μm long. Superior volsella developed and round. Inferior volsella nearly squared, basally flat. Gonocoxite 271–276, 274 μm long. Gonostylus racquet-shaped with anterior edge quadrate ( Figure 4 (b)), gonostylus 103–109, 106 μm long, with 2 megasetae 14–16, 15 μm and 12–13, 12 μm long, and one large and 2–3 smaller spines. HR 2.5–2.7, 2.6; HV 2.8–3.9, 3.2.

Female (n = 3).

Size. Total length 1.8–2.6, 2.3 mm. Wing length 2.2 mm, wing width 0.70 mm.

Coloration of mounted specimens. Head, dorsocentral and preepisternal regions of thorax, abdominal tergites, and genitals brown. Humeral region of thorax, abdominal sternites, wings halter and legs golden to golden-yellow.

Head ( Figure 4 (a)). Antenna 5 segmented, AR 0.29–0.32, 0.31, ultimate flagellomere 97 μm long with 12–14 sensilla clavata, antennal groove starts on the 4th segment. Temporal setae 4, including two outer verticals and two postorbitals. Frontal tubercle vestigial but visible. Clypeus rectangular, 58–70, 64 μm long and 104–111, 108 μm wide, with 8 setae, 54–68, 58 μm long. Eyes hairy. Tentorium narrow, 145–153, 149 μm long. Palp segment lengths (in μm): 62–77, 72; 46–49, 47; 50–72, 64; 65–81, 76; 133–161, 149; third palpomere with two sensilla clavata anterodorsally.

Thorax. Antepronotum with five lateral setae. Dorsocentrals 7–10 in single row. Acrostichals apparently two in mid-section. Prealars 5–6. Scutellars 4–5, in a single row. Humeral pit small.

Wing ( Figure 4 (b)). Costa extension 98–109, 104 μm long. Brachiolum with one seta; R with 6–7 setae, R1 with one seta, R4+5 with 5–6 setae, costa extension with 1–2 setae. Squama with 9–11 setae. Cu with slight bend at the tip.

Legs. Fore tibia with single spur 42–49, 46 µm long. Mid tibia with two spurs, 15–20, 17 µm, 20–25, 22 µm long. Hind tibia with two spurs, 20–26, 23 µm and 49–56, 53 µm long and with well developed comb with 15 spines. Pulvilli well-developed, almost half as long as the claws. Lengths and proportions of legs as in Table 2.

Genitalia ( Figure 4 (c–g)). Seminal capsules circular with necks having loops ( Figure 4 (c)), seminal capsule 60–65, 62 µm long, 60–61, 61 µm wide. Notum 86–90, 88 µm long. Dorsomesal lobe digitiform ( Figure 4 (c, d)). Ventrolateral lobe large and prominent ( Figure 4 (c, e)) Apodeme lobe distinct, long, and visible between principal lobes ( Figure 4 (c, f)). Tergite IX divided in two oval setigerous light patches ( Figure 4 (g)). Gonapophysis VIII with small, setose ventrolateral lobe. Cercus semi-circular, with pediform extensions ( Figure 4 (g)), 64–91, 77 µm long and 90–109, 105 µm wide.

Pupa (n = 4).

Size. Total length 3.1–3.9, 3.6 mm

Coloration of mounted specimens. Exuvia golden yellow.

Head ( Figure 5 (a)). Frontal apotome rugose basally with frontal tubercle cone-shaped, 25 µm long, 22 µm wide. Frontal setae 188–195, 192 µm long.

Thorax ( Figure 5 (b)). Thoracic horn covered with spines basomedially and laterally, apex more or less bare; apex rounded ( Figure 5 (c)), 212–316, 276 µm long, 58–63, 61 µm wide. Pc1–Pc3 on tubercles, 193; 237–270, 253; 242–299, 270 µm long respectively.

Abdomen ( Figure 5 (d-e)). Pedes spurii B present on segment II. Tergites I and VII–IX bare, tergite II with posterior spines on protuberance, tergites III with few median spines, Tergites IV–VI with median patch of hooklets and caudal spines in few rows ( Figure 5 (d)). Sternites IV–VI with posterolateral patches of spines (shagreen) ( Figure 5 (e)). Segment I with 1, segments II–V with 3 and segment VI with 4 L-setae ( Figure 5 (d)). Segment VII with 4 and segment VIII with 5 taeniate L-setae ( Figure 5 (d)). Anal lobe with 20–24, 22 setae in fringe (L = 275–403, 318 µm); 3 anal macrosetae 320–364, 347 µm long. Genital sacs not longer than anal lobes in males. Anal lobe 253–330, 287 µm long, 104–186, 144 µm wide; genital sac 193–216, 200 µm long, 97–126, 116 µm wide.

Fourth instar larva exuviae (n = 4, unless otherwise indicated)

Size. Total length about 4.1 mm (n = 1)

Coloration of mounted specimens ( Figure 7 (a)). Head capsule dark brown with occipital region much darker in contrast.

Head ( Figure 6 (a-d)). Head 339–378, 363 μm long, 345–404, 369 μm wide, HL/HW = 0.9. Antenna 5 segmented. Fifth and third segment longer than fourth. AR 2.0–2.4, 2.3. Blade 23 μm (n = 1) long, reaching the tip of fourth segment. Style 2.6 μm long (n = 1). Lauterborn organs robust covering third–fourth segments. Ring organ located at 1/5th from base of the first segment ( Figure 6 (a)). SI–SII simple and long. SIII not detectable. Pecten epipharynges with three subequal branches. Premandible 64–75, 71 μm long, simple with bulging accessory teeth ( Figure 6 (b)). Mandible 132–146, 139 μm long, 1 apical and 4 inner teeth, apical teeth subequal to the combined length of inner teeth. Seta subdentalis simple reaching the tip of 3rd inner teeth, seta interna with five branches ( Figure 6 (c)). Mentum 90–107, 97 μm long, 26–134, 129 μm wide, with wide bifid median tooth and six pairs of lateral teeth, median tooth about 3.8 × of the first laterals. Ventromental plate prominent, 62–77, 69 μm long, 10–14, 12 μm wide. Cardinal beard with six setae. Posterolateral margins of the mentum extend well-beyond the base of ventromental plates ( Figure 6 (d)).

Abdomen ( Figure 6 (e-f)). Procercus well-sclerotized, 39 μm long, 41 μm wide, with 2 small tubercles and 4 apical setae, each 342 μm long ( Figure 6 (e)). Posterior parapods 287 μm long, 103 μm wide, claws simple and dark ( Figure 6 (f)).

Distribution and Ecology. Adults collected near Hazen Camp, probably from the tributaries flowing into Lake Hazen.

Remarks. The adult males resemble that of D. dentatus , but the two species can be separated on the basis of antennal ratio, number of dorsocentrals and the shape and size of the sternapodeme, inferior volsella and the gonostylus ( Table 3).

Figures

Figure 2. Doncricotopus nunavummiuti sp. n., a-d adult male. a. Head; b. Antenna; c. Sensilla clavata on apex of 3rd palpomere; d. Thorax, lateral view.

Figure 3. Doncricotopus nunavummiuti sp. n., a-d adult male. a. Wing; b. Hypopygium; c. Anal point.

Figure 4. Doncricotopus nunavummiuti sp. n., a-f adult female. a. Head; b. Wing, c. Genitalia, ventral view; d. Dorsomesal lobe; e. Ventrolateral lobe; f. Apodeme lobe; g. Genitalia, dorsal view.

Figure 5. Doncricotopus nunavummiuti sp. n., a-d pupa. a. Frons; b. Thorax; c. Thoracic horn; d. Abdominal tergites, anal lobes and genital sacs; e. Sternites IV–VI.

Figure 6. Doncricotopus nunavummiuti sp. n., a-f larva. a. Antenna; b. Labro-epipharyngeal region; c. Mandible; d. Mentum; e. Procercus; f. Claws of posterior parapods.

Figure 7. Coloration contrast of Doncricotopus head capsules. a-b, larva. a. Doncricotopus nunavummiuti, paratype; b. Doncricotopus bicaudatus, holotype.