Stenochironomus roquei, Dantas, Galileu P. S., Hamada, Neusa & Mendes, Humberto F., 2010

Dantas, Galileu P. S., Hamada, Neusa & Mendes, Humberto F., 2010, A new Neotropical species of the genus Stenochironomus Kieffer (Diptera: Chironomidae) with wood-mining larvae, Zootaxa 2490, pp. 47-54 : 48-52

publication ID	https://doi.org/ 10.5281/zenodo.195585
DOI	https://doi.org/10.5281/zenodo.6199239
persistent identifier	https://treatment.plazi.org/id/414087F3-FFA4-FFEB-FF0F-3F907447FF1A
treatment provided by	Plazi
scientific name	Stenochironomus roquei
status	sp. nov.

Treatment

Stenochironomus roquei View in CoL sp. n.

Type material. Holotype, adult male with pupal and larval exuviae: BRAZIL, Amazonas State, Itacoatiara, Madeireira Mil, 02°46’43.1’’S, 58°38’54.0’’W, 14.IV.09, in submerged wood, leg. G.P.S. Dantas & S.C. Escarpinati ( INPA, slide-mounted in Euparal). Paratypes (same data as holotype, except for coordinates and/ or date): 1 male with pupal exuviae, 02°43’40.7’’S, 58°39’16.6’’W, 08.V.09; 1 male with pupal exuviae, 02°47’32.1’’S, 58°27’42.4’’W; 1 male, 19.V.09 ( MZUSP); 1 male, 20.IV.09; 1 larva, 20.VI.09.

Diagnostic characters. The male imago can be separated from all other species of the genus by having a dark brown patch on anterior portion of lateral vittae, extending laterally to parapsidal suture; AR up to 2; thirteenth flagellomere very long, up to 1100 µm; a superior volsella markedly elongated; a very long inferior volsella with 6 setae, the apical one being stout; anal point slightly larger at apex; a very long and curved gonostylus. The pupa is distinguished by the presence of pedes spurii B in TII; frontal apotome elongated; hooklets on T II smaller near the median extremities of the row; spur on S VIII with 7–6 brownish teeth. The larvae can be recognized by a paralabial plate with weak striae near to anterior margin; SI and SII pinnate, SIII bifurcated; labiohypopharynx with ligular lobes truncated with small projection on lateral margin; superior pair of anal papillae with two constrictions while inferior pair has only one.

Etymology. This species is named in honour of Dr. Fabio de O. Roque for his contributions to the knowledge of Brazilian Chironomidae .

Description. Adult male (n = 5, except when otherwise stated).

Total length 6.55–6.72, 6.62 mm. Wing length 2.87–2.97, 2.92 mm. Total length/wing length 2.21–2.34, 2.27. Wing length/length of profemur 1.35–1.42, 1.39. General coloration yellowish. Eyes markedly metallic green. Thorax with a dark brown patch on anterior portion of the lateral vitae, extending laterally to the parapsidal suture. Fore tarsus dark; fore tibia yellowish with proximal portion dark; mid and hind legs yellowish. Wing mostly clear with light brown distal portion, not easy to observe in mounted material. Abdomen nearly uniformly yellowish to orange, ornamented with many dark setae; hypopygium dark.

Head ( Fig. 1 View FIGURE 1 A). AR 2.23–2.40, 2.32. Ultimate flagellomere 1161–1183, 1171 µm long. Temporal setae 8– 12, 11. Clypeus with 28–42, 36 setae. Tentorium, stipes and cibarial pump as in Figure 1 View FIGURE 1 A. Tentorium 231– 237, 234 µm long; 44–50, 48 µm wide at sieve pore; 25 µm wide at posterior tentorial pit. Stipes 200–231, 213 µm long; 8–11, 10 µm wide. Palpomere lengths (in µm): 57–71, 66; 63–68, 66; 323–354, 334; 170–196, 182; 300–356, 335.

Thorax ( Fig. 1 View FIGURE 1 B). Ac 8–11, 9; Dc 6-9, 8 in a single row; Pa 3–5, 4; Scts 9–11, 10 in a single row. Anterior edge of scutum rounded in lateral view.

Wing ( Fig. 1 View FIGURE 1 D). VR 1.05–1.09, 1.07. Brachiolum with 2–5, 3 setae. R with 53–62, 57 setae; R1 with 44– 70, 58 setae; R4+5 with 51–83, 66 setae; M with 1–6, 3 setae; RM with 0–1, 0 setae; remaining veins bare. Squama with 6–11, 8 setae.

Legs. Scale of front tibia 69–73, 72 µm long, with 3 strong setae, the longest 250–297, 269 µm; spurs of middle tibia 51–61, 56 µm and 60–64, 61 µm long; spurs of hind tibia 54–62, 59 µm and 64–67, 65 µm long. Apex of fore tibia 91–100, 95 µm wide, of mid tibia 100–108, 104 µm wide, of hind tibia 103–112, 106 µm wide. Lengths (in µm) and proportions of legs as in Table 1.

Hypopygium ( Figs. 1 View FIGURE 1 C, 2A, 2B). Anal point as in Figure 2 View FIGURE 2 C, 150–166, 158 µm long; 19–24, 22 µm wide at base; 17–20, 19 µm wide at apex; curved in lateral view, with apex slightly bent upwards ( Fig. 2 View FIGURE 2 C); with 13–23, 17 setae on each side. Tergite IX with 70–81, 74 strong setae in a central field, caudal apex wedgeshaped in dorsal aspect. Laterosternite XI with 6–7, 7 setae. Phallapodeme 196 (1) µm long; transverse sternapodeme 41–50, 45 µm long. Gonocoxite 266–280, 275 µm long; inferior volsella 362–396, 383 µm long, with 5–6, 6 setae, restricted to apical fourth, apical seta blunt and stout; superior volsella 118–139, 129 µm long, with 6–9, 7 setae distributed along most of its length. Gonostylus curved, 299–324, 314 µm long.

Pupa (n = 3).

Total length 7.92–8.41 mm. Coloration: cephalothorax gray to brownish, wing sheath mostly transparent with darkened margin. Abdomen light brownish, with lateral margin from distal half of TIV to TVIII brownish. Spur on SVIII brownish, teeth with distal portion darker than basal portion.

Cephalothorax. Frontal apotome elongated (Fig. 3A). Precorneal seta 2; 83–89 µm long. Thoracic horn composed of a stout spinose branch (Fig. 3C) and several smooth branches with a plume-like appearance. Dorsocentrals (Dc) 50–75 µm long. Distance between Dc1 and Dc2 3 µm; between Dc2 and Dc3 296 µm; between Dc3 and Dc4 4 µm; two additional setal pits present; median suture granulose (Fig. 3B).

fe ti ta1 ta2 ta3 ta4

p1 2077–2127, 2100 1730–1822, 1769 2698–2965, 2771 1370–1478, 1420 1067–1172, 1131 877–960, 934 p2 1747–1820, 1778 1454–1480, 1468 1028–1089, 1067 525–562, 544 415–454, 434 233–255, 243, p3 2031–2084, 2059 1756–1801, 1772 1331–1423, 1379 706–785, 750 594–652, 619 324–353, 336

ta5 LR BV SV BR

Abdomen (Fig. 3D, 3E). TI bare; TII–V with median, large field of shagreen; TVI with two patches of shagreen, a weak central field in the oral part and a stronger caudal patch of shagreen that extends laterally on posterior margin; TVII–VIII bare; anal segment with an anterior pair of shagreen patches. TII with posterior row of hooklets extending to lateral margin of tergite, divided medially into two groups separated by 224–262 µm, hooklets being smaller near to median extremities, with 37–43 hooklets on each side. Abdominal setation: SI without L setae; SII–IV with 3 L setae, all hair-like; SV–VII with 4 LS setae all taeniate; SVIII with 5 LS setae, all taeniate. Pedes spurii B present on segment II ( Fig. 1 View FIGURE 1 E). Spur on S VIII with 6–7 brownish teeth (Fig. 3F). Genital sac 475–508 µm long, overreaching the posterior margin of the anal lobe by 68–115 µm; apex of anal lobe rounded, with fringe of about 110 filaments.

Stenochironomus roquei n. sp., pupa. A, frontal apotome, B, cephalothorax, C, branch of thoracic horn, D,

tergites I–V, E, tergites VI–IX, F, spur on T XIII.

Fourth-instar larva (n = 1–2).

Total length 15.01 mm. IC 0.85–0.86.

Head ( Fig. 1 View FIGURE 1 F). Antenna as in Figure 4 View FIGURE 4 A; lengths of antennal segments (in µm): 97–105; 21–30; 11–14; 11–14; 5–7. Blade 28–31 µm long. Labrum as in Figure 4 View FIGURE 4 B. Labral lamella with two groups of spicules arranged comb-like, spicules of pecten epipharyngis composed of two branches, each with 7–8 teeth apically ( Fig. 4 View FIGURE 4 B). SI palmate, 28 µm long; SII pinnate, 33 µm long; SIII bifurcate, 31 µm long. Premandible 103 µm long, with brush composed of about 40 setae. Mandible ( Fig. 4 View FIGURE 4 C) 266–280 µm long, with 4 inner teeth. Mentum ( Fig. 4 View FIGURE 4 D) convex 190–213 µm wide, with 12 blackish teeth, first and second median teeth arranged in a linear way, remaining four lateral teeth arranged in an ascendant way except for the fourth, which is smaller and positioned ventrally in relation to the third; micropore located anterolaterally to setae submenti; paralabial plate with weak striae near anterior margin. Base of dorsolateral strip originating on half of dorsomedian strip. Labiohypopharynx ( Fig. 4 View FIGURE 4 E) with ligular lobes truncated, with small projection on lateral margin, cleft between lobes very narrow, nearly parallel-sided to V-shaped.

Abdomen. Procercus with 4 filaments. Anal papillae ( Fig. 4 View FIGURE 4 F): superior pair with two constrictions, basal portion 540 µm long, median portion 374 µm long, apical portion 317 µm long; inferior pair with a single constriction, basal portion 545 µm long, apical portion 459 µm long. Longest anal hook 104 µm long.