Stenochironomus palliaculeatus Borkent

Dantas, Galileu P. S., Hamada, Neusa & Mendes, Humberto F., 2016, Contribution to the knowledge of Stenochironomus Kieffer (Diptera, Chironomidae) from Brazil: seven new species and description of females and immatures of some previously known species, Zootaxa 4117 (1), pp. 1-47 : 38

Stenochironomus palliaculeatus Borkent

( Fig. 28 )

Material examined. Brazil, Amazonas state: Manaus, 3º 05’43.39’’ S, 59º 59’ 24.91’’ W, 1 male and two females, 13.viii.2008, manual collection, G.P.S. Dantas ( INPA).

Diagnostic characters. Male: thorax legs and abdomen without dark pigmentation; anal point straight and slender (see Borkent, 1984). Female: without dark pigmentation; post-genital plate with rounded apex; spermathecal duct annulated.

Female (n = 2, except when otherwise stated). Total length 2.97–3.22 mm. Wing length 1.95–1.97 mm. Total length/ wing length 1.51–1.65. Wing length/ length of profemur 1.66–1.70.

Coloration: body, wings and legs completely pale to pale.

Head. Flagellomere lengths (1) (in µm): 112; 102; 123; 126; 143. Longest seta 397–439 µm long. AR (1) 0.32. Temporals 15–17. Clypeus with 29–30 setae. Tentorium 189 (1) µm long; 26 (1) µm wide at sieve pore; 13 (1) µm wide at posterior tentorial pit. Stipes (1) 168 µm long. Palpomere lengths (in µm): 36–40; 48–52; 194–202; 141– 145; 154–296.

Thorax. Acrostichals 14–15 (extending to the anterior margin of scutum); dorsocentrals 30–31 in two rows; prealars 11–13, irregularly distributed. Scutellum with 19–23 setae in two rows.

Wing. VR 1.20–1.21. Brachiolum with 2 setae. R with 60 setae; R1 with 64 setae; R4+5 with 97 setae; RM with 6 setae; M with 7 setae; remaining veins bare . Squama with 12 setae.

Legs. Scale of front tibia 44–48 µm long; spurs of middle tibia 33–34 µm and 44–45 µm long; spurs of hind tibia 31(1) µm and 40–44 µm long. Apex of fore tibia 60–62 µm wide, of mid tibia 61–62 µm wide, of hind tibia 68–75 µm wide. Lengths (in µm) and proportions of legs as in Table 8.

Genitalia ( Figs. 28 A, 28B): Tergite IX with 39–41 setae; gonocoxite IX 4–5 with setae. Cercus 102–124 µm long. Notum 244–255 µm long. Coxosternapodeme IX 102–125 µm long. Post-genital plate with rounded apex. Spermathecal duct annulated.

fe ti ta1 ta2 ta3 ta4

p1 1160–1177 1110–1117 1465–1737 772–916 607–750 505–604

p2 1067–1076 929–947 678–705 364–379 253–258 149–155

p3 1188–1200 1116–1171 857–888 529–540 401–408 247–255 ta5 LR BV SV BR

p1 246–275 1.32–1.55 1.58–1.75 1.32–1.55 3.3–5.2

p2 86–94 0.73–0.74 3.10–3.12 2.87–2.94 1.7–3.6

p3 104–106 0.76–0.77 2.44–2.51 2.66–2.70 4.1–4.4 Pupae and larva unknown.

Notes on biology of the species. Some males and females were collected close to a light source in an urban area of Manaus city at 6:30 pm, and the males were identified as S. palliaculeatus . However, despite males and females have been collected together, without the association with the immature stages, we cannot be sure that both males and females belong to the same species, since there may be more than one completely pale sympatric Stenochironomus species. Thus, this association should be treated as a tentative.

Figures

FIGURE 28. Stenochironomus palliaculeatus Borkent, adult female. A, genitalia, dorsal view. B, genitalia, ventral view.