Oleia fieldsi Silva, 2018

Silva, Fabio Laurindo Da & Song, Chao, 2018, Oleia fieldsi sp. n., a new Orthocladiinae (Diptera: Chironomidae) species from the Brazilian Atlantic rainforest, Zootaxa 4526 (1), pp. 96-100 : 97-98

Oleia fieldsi Silva et Song sp. n.

( Fig. 1 )

Type examined. Holotype, 1 male, BRAZIL: Paraná, Foz do Iguaçu, Iguaçu National Park , 25.62010° S and 54.47547° W, 13.x.2017, leg. A. Kiszewski, E.S. Dias, F.L. Silva & R.C. Oliveira ( NTNU-VM, slide 201776) . Paratypes: 3 males, same data as for holotype ( MZSP) .

Etymology. Named in honor of Rogério Campos ‘Fields’ de Oliveira, researcher, colleague and friend, for assistance in collecting the new species.

Diagnostic characters. The male adult of Oleia fieldsi sp. n. differs from that of other Oleia species by the combination of the following characters: anal point basally broad; gonostylar anterior branch with 5 strong setae.

Description. Male (n = 4). Size. Total length 1.96–2.36 mm. Wing length 1.18–1.25 mm. Total length/wing length 1.66–1.89. Wing length/length of profemur 2.34–2.99.

Coloration. Head brown, maxillary palp pale brown. Thorax pale brown, with dark brown vittae, postnotum, median anepisternum, preepisternum, and epimeron II. Wing clear with membrane transparent and crossveins pale, without spots. All legs pale brown. Abdominal tergites brown with bases of abdominal setae and anterior and posterior bands pale brown. Hypopygium pale brown with brown anal point.

Head. Eye bare, reniform, without dorsomedian extension. Antennal flagellum missing, diameter of pedicel 91–110 µm. Temporal setae 8–10, irregularly uniserial, inner verticals weak, outer verticals and postorbitals strong. Frontal tubercle absent. Tentorium 117–142 µm long. Clypeus 51–70 µm long, 53–71 µm wide at largest part, bearing 5–6 setae. Cibarial pump 117–142 µm long, with anterior margin concave. Lengths of palpomeres 1–5 (in µm): 24–29 (3); 29–33 (3); 50–64 (3); 44–46 (3); 69–81 (3). Third palpomere with 3 lanceolate sensilla clavata grouped at apical sensillum coeloconicum.

Thorax. Antepronotal lobes narrowly separated, antepronotum with 3 setae. Acrostichals 14–19, decumbent, uniserial to biserial, starting at some distance from antepronotum. Dorsocentrals 6–8, simple, uniserial. Prealars 4, 3 posterior and 1 anterior. Supraalar 1. Scutellum with few 4 setae in single row.

Wing ( Fig. 1A ). Width 0.3–0.4 mm, membrane without setae with fine punctation. Anal lobe protruding. VR 1.43–1.52. WW 0.29–0.30. Costa 1.00–1.10 µm long. R 4+5 ending above M 3+4, FCu distal to RM. Brachiolum with 3 setae. Veins bare. Squama bare.

Legs (in µm). Fore leg: width at apex of tibia 19–29, tibia with single, apical spur 34–46; ta 1-4 without preapical pseudospurs. Mid leg: width at apex of tibia 23–29, tibia with two apical spurs 11–15; 13–27; ta 1-4 without preapical pseudospurs. Hind leg: width at apex of tibia 26–40, tibia with two apical spurs 17–23; 39–43; comb with 10–12 bristles; ta 1-4 without preapical pseudospurs. Sensilla chaetica absent. Claws slender, distally recurved and pointed. Pulvilli vestigial. Lengths and proportion of leg segments as in Table 1.

Hypopygium ( Figs 1 B–D). Tergite IX with few setae to each side of anal point. Laterosternite IX with 4–5 setae. Anal point narrow and elongate, 53–57 (2) µm long, 16–18 (2) µm wide at base, with 14–16 (2) strong setae ( Fig. 1B ). Phallapodeme well developed, with curved oral projections, 79–86 µm long; transverse sternapodeme anteriorly arched, oral projections barely indicated, 106–127 µm long. Penis cavity with horse-shoe shaped basal sclerite, 11–14 µm wide ( Fig. 1C ); virga consisting of several separate sclerites. Gonocoxite 97–109 µm long, 39– 45 µm wide with low, rounded inferior volsella. Gonostylus trifid as in figure 1D, posterior branch 63–74 µm long, separated to base, with 10–12 (3) marginal setae, and 21–24 (2) µm long subapical megaseta; median branch oblong, 53–58 µm long, with row of 11 strong, curved marginal setae, longest 16–21 µm long, anteriomedian corner with weaker setae, longest 21–22 (2) µm long; anterior hyaline branch spoon-shaped, with 5 moderately strong setae, longest 14–27 (3) µm long. HR 2.26–2.59, HV 1.36–1.63.

Female, pupa and larva. Unknown

Ecology. Adult males of Oleia fieldsi sp. n. were collected near a reservoir in a fragment of secondary forest in the Brazilian Atlantic Forest, with canopy intercepting 20% of sunlight, at Iguaçu National Park, on the border of the Argentinian province of Misiones and the Brazilian state of Paraná. According to Andersen & Mendes (2007), the immature stages of Oleia might be terrestrial or semiterrestrial given the proven difficult to locate them.

Figures

FIGURES 1A–D. Oleia fieldsi Silva et Song sp. n., adult male. A. Wing (scale bar = 500 µm). B. Tergite IX and dorsal aspect of gonocoxite, anal point and sternapodeme in detail (scale bar = 50 µm). C. Dorsal aspect of gonocoxite, phallapodeme in detail (scale bar = 50 µm). D. Ventral aspect of gonocoxite, gonostylar anterior branch in detail (scale bar = 50 µm).