Riethia fazzari, 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 : 255-256

Riethia fazzari sp. n.

( Fig. 9 )

Type material. Holotype: Male, slide mounted in Euparal, Brazil, São Carlos, SP, Fazzari stream, 24.i.2000, F. Roque (I1-11, LEIA-UFSCar).

Derivation nominis. The name fazzari refers to the type locality, Fazzari stream (Campus UFSCar). The name is treated as a noun in apposition.

Diagnostic characters. Adult male of Riethia fazzari sp. n. differs from all other species of the genus by the combination of the following characters. Adult male: hypopygium with caudal projection U-shaped with few setae on apex. Superior volsella hooklike, with short simple setae. Median volsella short with three long setae. Inferior volsella large and distally truncated with four long simple distal setae and numerous dorsal and ventral little setae.

Description. Male (n = 1). Total length near 2.85 mm. Wing length 1.45 mm.

Colouration. Thorax, abdomen and legs pale brown.

Head. Temporal setae not discernable in slide preparation. Clypeus with 7 setae. Antenna 0.71 mm long; AR 1.09. Palpomere 2–5 lengths: 81, 81, 88, 125 µm.

Thorax. Ac 16 biserial, beginning near antepronotum; Dc 11; Pa 2; Scts 8.

Wings ( Fig. 9a ). VR 1.07. Brachiolum with two setae. Veins setae on R, R1 and R 4+5 not discernable in slide preparation. Squama with six setae.

Legs. Scale on fore tibia 46 µm long, with a short spine at apex. Tibial combs of mid and hind legs partially fused; mid tibial spur anterior, 60 µm, posterior 65 µm long; hind tibial spur anterior, 69 µm, posterior 66 µm long. Lengths and proportions of legs as in Table V.

TABLE V. Lengths (in µm) and proportions of Riethia fazzari sp. n. male (1).

Hypopygium ( Fig. 9b, c ). Tergite IX with unusual caudal projection U-shaped. Laterosternite IX with 4 setae. Transverse sternapodeme 88 µm long with strong oral projections. Phallapodeme 106 µm long. Gonocoxite 162 µm long. Superior volsella hooklike, with three simple short setae on external margin and three strong setae on internal margin. Median volsella inconspicuos, bearing three simple strong setae. Inferior volsella large, distally truncated, with four ventral long setae on internal margin and dorsal and ventral setose distally. Gonostylus 162 µm long. HR 1.

Figures

FIGURE 9. Riethia fazzari sp. n. male. (a) Wing.(b) Hypopygium.(c) Hypopygium, right ventral l view, left dorsal view.