Pseudochironomus boraceia, Trivinho-Strixino & Shimabukuro, 2018

Trivinho-Strixino, Susana & Shimabukuro, Erika Mayumi, 2018, Brazilian Pseudochironomini (Diptera: Chironomidae) Part 2. New Pseudochironomus and Riethia species, Zootaxa 4403 (2), pp. 245-260 : 250-252

Pseudochironomus boraceia sp. n.

( Fig. 6 )

Type material. Holotype: Male, slide mounted in Euparal, Brazil, São Paulo, Salesópolis, 18.ix.2007, light trap, leg. Fröehlich, C. G. (I1-06, LEIA-UFSCar). Paratypes: 2 males, as holotype, 12.x.2001 (I1-07, I1-08, LEIA- UFSCar).

Derivatio nominis. The name boraceia refers to the type locality, Boracéia Park. The name is treated as a noun in apposition.

Diagnostic characters. Adult male of Pseudochironomus boraceia sp. n. differs from all other species of the genus by the combination of the following characters. Adult male: acrosticals present on thorax; hypopygium with a protruding end and without anal point; hooklike superior volsella, with three simple setae and the internal projection sclerotized; median volsella short semi triangulate with one or two large setae; pars ventralis divided only at the apex; inferior volsella enlarged distally with microtrichia and several marginal large setae.

Description. Male (n =3). Total length 4.47–5.64 mm. Wing length 2.15–2.46 mm.

Coloration. Thorax brown with dark brown vitae; abdomen with transversal brown bands on each segment. Legs dark brown.

Head. Temporal 20–23 setae. Clypeus with 31 setae. Antenna 1.23–1.50 mm long; AR 1.51–2.01. Palpomere 2–5 lengths: 55–75, 175, 213–225, 288–337 µm.

Thorax ( Fig. 6a ). Ac 5–6; Dc 9; Pa 4–5; Scts 18–22.

Wings ( Fig. 6b ). Width 0.60–0.77 mm. VR 1.03–1.10. Brachiolum with two setae. Veins setae on R with 17– 19, R1 with 0–1, and R4+5 with 0–1 setae. Squama with 16–22 setae.

Legs. Scale on fore tibia 58–72 µm long, with a spine at the apex. Tibial combs of mid and hind legs partially fused; mid tibial spur anterior, 58 µm, posterior 78 µm long; hind tibial spur anterior, 66 µm, posterior 88 µm long. Lengths and proportions of the legs as in Table II.

TABLE II. Lengths (in µm) and proportions of legs of Pseudochironomus boraceia sp. n. male (3).

Hypopygium ( Fig. 6c, d ). Tergite IX without anal point. Laterosternite with ten setae. Transverse sternapodeme 77–97 µm long (2), with developed oral projections. Phallapodeme 83–110 µm long (2). Pars ventralis narrow, 57 µm long, partially divided at the apex. Gonocoxite 118–128 µm long. Superior volsella hooklike ( Fig. 6e ), with three preapical simple setae and internal projection sclerotized. Median volsella semitriangular with 1–2 simple setae near apex. Inferior volsella pubescent with several marginal large and ventral setae ( Fig. 6e ). Gonostylus 146–158 µm long. HR 1.00–1.22.

Figures

FIGURE 6. Pseudochironomus boraceia sp. n. male. (a) Thorax. (b) Wing. (c) Hypopygium. (d) Hypopygium, right ventral view, left dorsal view.(e). Superior and inferior volsellae.