Orthonevra chilensis Thompson 1999
Creators: name: Miranda, Gil F. G.
name: Soares, Matheus M. M.
name: Thompson, Christian
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Diptera
Syrphidae
Orthonevra
Orthonevra chilensis

description: Orthonevra chilensis Thompson, 1999
Orthonevra chilensis Thompson 1999: 346, figs (wing, male genitalia). Type-locality: Chile, Vina del Mar (HT M UCS). Thompson 2006: 121 (catalog citation), 21 (key reference); Barahona-Segovia et al. 2021: 20 (catalog citation, conservation status).
Figs 7 and 8. Map: Fig. 39
Redescription. MALE. Head (Fig. 7d–f): metallic blue, face wide, with convexity in profile and ventral ¼ slightly produced anteriorly as a strong convexity, regulose except for smooth ventral ¼, shiny with sparse white pile but bare medially; with white microtrichose subtriangular macula laterally, positioned immediately ventral to antennal base, and separated from antennal base; mala mostly smooth. Antenna dark, except pedicel pale laterally and postpedicel pale baso-ventrally; pedicel short but slightly longer than scape, postpedicel with mostly straight dorsal surface and convex ventral surface, with a shallow concavity pre-apically on dorsal surface, 2.5 × longer than the pedicel. Mala produced apico-ventrally, with weak regulae. Gena shiny, smooth, and with white pile. Frontal triangle shiny, rugose, uniformly covered with erect and sub-appressed white pile, without median longitudinal groove; lunule almost indistinguishable from frontal triangle. Vertical triangle isosceles triangle-shaped, 10 × the length of the eye contiguity, dark blue metallic, uniformly covered with long, erect, black pile on ocellar triangle and posterior to it. Occiput not visible laterally on dorsal 1/3, homogeneously covered in white microtrichia, and with one to two (ventrally) rows of white pile. Eyes very narrowly holoptic; with a slightly sinuous sub-anterior vitta that connects dorsally and ventrally to anterior dark margin, a medial straight vitta and a medial fascia disappearing close to posterior end.
Thorax (Fig. 7d, e): metallic blue, homogeneously covered with densely distributed, short, black pile, longer and white on notopleuron; scutum with four complete separate dark matte vittae, with inconspicuous vittate smooth macula laterally on scutum posterior to transverse sulcus and on notopleural sulcus; scutellum metallic blue and somewhat darker medially, slightly depressed on apical margin, covered with very short black pile, protuberances very weak. Pleuron metallic blue, mostly smooth with few areas with fine microsculpturing, with short white pile on antepronotum, proepisternum, proepimeron, posterior anepisternum, anteriorly on anepimeron, very few on a dorsal and ventral patch on katepisternum, and on katatergum, metasternum bare. Calypter white with long white marginal pile, ventral lobe margin darker. Plumule white. Halter yellowish.
Legs (Fig. 7e): metallic dark, except tibiae and first tarsomere paler and with weaker metallic reflections. Legs covered with white pile, longer ventrally on femora, apex of mesotibia and mesotarsomeres with ventral black setulae, metafemur lacking black setulae.
Wing (Fig. 7e): hyaline, without any maculation; stem and C vein pale basally; vein R2+3 reaches C apically to the level of the intersection of M1 with R4+5, vein M1 slightly recurrent; wholly microtrichose; basicosta with dense appressed pale to dark pile, with two more prominent black setae apically. Alula large, 2 × the width of the cell c.
Abdomen (Fig. 7d, e): metallic blue, but with large matte black area medially from terga 1 to 4; pile sockets as small protuberances, pile black, appressed and short, longer and white laterally on tergum 1 and baso-laterally on tergum 2; sterna dark metallic, with longer white appressed pile, erect on sternum 2; sternum 4 with apical margin straight.
Genitalia (Fig. 8d–g): surstylus gently curving toward middle, mostly narrow but base extends ventrally, base slightly extended dorsally, with a rounded apex, mostly with long pile but bare on baso-lateral 1/3 (Fig. 8d); subepandrial sclerite arms wide; cercus oval and not extended as in other Orthonevra. Hypandrium basal 2/3 oval, apical 1/3 straight and narrow, apex sheathing the phallus dorsally, with anterior ventral notch flanked by laminae that leave it as a short ventral slit; postgonites as heavier sclerotized pedunculate structures rising dorsal to the ventral notch laminae, ending in an oval apex with an acute projection (Fig. 8e, f); phallus mostly straight, but apex slightly expanding and then tapering into an acute point, with a ventral extension anterior to basal tubular process, basal tubular process short and medially positioned.
Variation. Eye medial straight vitta not always visible.
FEMALE (Fig. 7a–c, 8a–c). Like male except: face convexity weaker, almost straight; mala more produced; frons regulose, except smooth around lunule, and with median longitudinal groove ending in the middle of the frons; lunule smooth; pile posterior to ocellar triangle white; eye with sub-posterior dark vitta as well; metabasitarsomere dark. Genitalia (Fig. 8a–c): tergum 7 rectangular, with a few pile on anterior margin. Sternum 7 rectangular and narrow, with a few pile on anterior margin. Tergum 8 large and quadrangular, sparsely pilose apico-laterally. Sternum 8 large, apical margin deeply concave wholly pilose except bare baso-laterally. Sternum 9 has a pair of heavier sclerotized triangular plates, with their apical vertex hooked and ending close to the apex of sternum 8, plates connected by a weaker sclerotized area medially. Epiproct rectangular with a small apical ‘V-shaped’ antero-medial notch and without basal apodemes, with a few pile latero-medially. Cercus semi-oval, with a truncate basal margin, pilose on apical 1/3, positioned apically to epiproct. Hypoproct mostly membranous, with medial pigmented area, with a few pile only on apex of pigmented area.
Length. Body 4.74–5.16mm (n=3), wing 3.75–4.01mm (n=3); female 4.69–5.88mm (n=3), wing 4.01–4.79mm (n=3).
Distribution. Chile (Fig. 39).
Altitudinal range. 50–500m.
Comments. With O. quadristriata, it is one of the only species studied virtually without any maculation on the wing and a slightly recurrent M1 vein. Orthonevra chilensis is the only Orthonevra species studied that lacks black setulae on the metafemur, also unique are the bare metasternum, the unique condition of the postgonite of the male genitalia (O. quadristriata also has a pedunculate postgonite (Fig. 31h–j) but not so modified as in O. chilensis) and rectangular female epiproct with a small medial notch. This is the first time the female is described. This species is endemic to Chile and only occurs in low altitudes west of the Andes.
Type material: CHILE. Valparaíso, Viña del Mar [ca 32°59’34.0”S 71°32’13.4”W], 4.iv.1917, P. Herbst (male holotype chilensis UCS, USNMENT01492691).
Additional material examined: CHILE. Coquimbo, Tilama [ca 32°5’11.59”S 71°10’2.13”W], El Naranjo [?], ??. x.1967, L.E. Peña (4 male and 5 female paratypes MZUSP, USNMENT01492601–608, …696).
description: Published as part of Miranda, Gil F. G., Soares, Matheus M. M. & Thompson, Christian, 2024, The Neotropical Orthonevra Macquart, 1829 (Diptera: Syrphidae), pp. 1-78 in Zootaxa 5484 (1) on pages 18-20, DOI: 10.11646/zootaxa.5484.1.1, http://zenodo.org/record/13208985