Orthonevra shannoni
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 shannoni

description: Orthonevra shannoni (Curran, 1926)
Chrysogaster shannoni Curran 1926: 119. Type-locality: Costa Rica, San Mateo, Higito [ca 9°56'03.1"N 84°31'27.7"W] (HT male USNM). Fluke 1957: 50 (catalog citation).
Orthonevra shannoni. Thompson et al. 1976: 91 (catalog citation); Thompson 2006: 121 (catalog citation), 22 (key reference).
Figs 34 and 35. Map: Fig. 39
Redescription. MALE. Head (Fig 34d–f): metallic blue, face with slight convexity in profile and ventral ¼ slightly produced anteriorly as a weak convexity, regulose except for smooth area between the oral margin and convexity, shiny, with sparse white pile and not scale-like; with small white microtrichose subtriangular macula laterally, positioned immediately ventral to antennal base and widely separated from it. Antenna yellow, except post-pedicel mostly dark but with pale base; pedicel twice the length of the scape, postpedicel oval elongated, 1.5 × the length of the pedicel. Mala slightly produced apico-ventrally, with weak regulae. Gena shiny, smooth, and with white pile. Frontal triangle shiny, regulose, bare except for distinct erect white pile anterior to eye contiguity and following eye margin, with median longitudinal groove not reaching the lunule. Vertical triangle isosceles triangle-shaped, 2 × longer than eye contiguity, metallic green, with very short and sparse pale pile on ocellar triangle and posterior to it. Occiput not visible laterally on dorsal 1/3, ventral 2/3 homogeneously covered in white microtrichia, with very short black pile on dorsal 1/3, bare medially, and with sparse and slightly longer white pile on ventral ¼. Eyes holoptic; covered with dark spots, medially the markings form two to four irregular circular markings.
Thorax (Fig. 34d, e): metallic blue-green, mostly bare, with a few very short pale pile laterally; scutum with four complete dark matte vittae, but medial pair mostly fused posteriorly, with a short narrow lateral vittate macula posterior to transverse sulcus; scutellum metallic blue-green with medial matte black vitta as wide as fused medial vittae of scutum, and matte dark laterally, mostly bare with very short pale pile baso-laterally. Pleuron metallic blue, smooth on anterior anepisternum and proepimeron, with short white pile on antepronotum, proepisternum, ventral patch on katepisternum, katatergum and metasternum, inconspicuous on posterior anepisternum, dorsal patch of katepisternum. Dorsal lobe of calypter white with white marginal pile, ventral lobe white with longer white marginal pile. Plumule white. Halter yellowish.
Legs (Fig. 34e): dark with metallic blue reflections, except apex of femora, basal 1/3 of tibiae and tarsomeres 1–2 yellow. Legs covered with short pale pile, slightly longer postero-apically on mesofemur, apex of mesotibia and mesotarsomeres with ventral black setulae, metafemur with ventral surface with short, black setulae.
Wing (Fig. 34d): hyaline, with dark vittae sub-apically (from end of R2+3 until the end of M1), sub-apically on r1, and on dm-m, with one weak fasciate macula in cells r2+3 and dm and two in r4+5, and a faded spot apically in r2+3 and posteriorly to end of R4+5; stem vein and vein C pale basally, wholly microtrichose except for small bare area posterior to pseudovein; basicosta with short appressed white pile and one prominent black seta apically. Alula large, 2 × the width of the c cell.
Abdomen (Fig. 34d, e): metallic blue, terga 2–4 matte black on apical margin, pile sockets as small protuberances, pile inconspicuous white, appressed and short, much longer and erect baso-laterally on tergum 2; sterna metallic, with white appressed pile; sternum 4 with right side slightly produced.
Genitalia (Fig. 35c–f)): surstylus bent in a right angle at basal ¼, basal ¼ with a subtle rounded carina anteriorly, with a ventral triangular lamina sub-basally, and apex slightly acute, with long pile sparsely distributed dorsally (Fig. 35c); cercus sub-triangular, with concave dorsal margin, with long pile. Hypandrium compressed submedially, with anterior narrow ventral notch V-shaped through ½ the length of the hypandrium, notch with carina on each side, ending anteriorly on flattened bi-lobate projection (ventral sub-basal lobe minuscule, dorsa lobe finger-like in profile) (Fig. 35e); postgonites laterally compressed, bi-lobate (ventral lobe as a sub-triangular lamina, dorsal lobe slightly converging towards the middle), with dense pile on dorsal and lateral surfaces (Fig. 35d); phallus compact, with apex forming a ventral acute projection, with apico-dorsal short carinae, basal tubular process as a long sclerotized tube, gently curving and directed apically (Fig. 35f).
FEMALE (Figs 34a–c, 35a, b). Like male except: more metallic blue; frons metallic blue, wide, strongly regulose, with a medial longitudinal groove extending from ocellar triangle through the dorsal ¾ of the frons; wing with apex more distinctly dark; tergum 5 entire. Genitalia (Fig. 35a, b): Tergum 7 as roughly sclerotized squared areas, bare. Sternum 7 as a sclerotized strip, with pile on apical margin. Tergum 8 as two sub-triangular plates, bare. Sternum 8 heart-shaped (in ventral view) with sub-triangular indentation on apical margin, sclerotized, mostly pilose, with apico-lateral depression. Sternum 9 as a pair of two irregular sclerotized strips flanking the genital opening. Epiproct dorsal surface convex, sub-quadrate, with convex apical margin, with two very short baso-lateral apodemes, pilose on apical ½. Cercus oval, mostly pilose, positioned apico-ventrally to epiproct. Hypoproct as a membranous mostly pilose area, slightly sclerotized apically.
Length. Body 4.54–4.99mm (n=2), wing 3.38–3.54mm (n=2); female 4.7mm (n=2), female 3.5–3.6mm (n=3).
Distribution. Brazil (Roraima), Colombia, and Costa Rica (Fig. 39).
Altitudinal range. 250–2560m.
Comments. The eye pattern promptly distinguishes this species from other Orthonevra; the spots form circular markings medially (Fig. 34c, f) similar to the vittate markings present in the other species. The female epiproct is similar to that of O. neiae sp. nov., but proportions of segment 8 and the proctiger can distinguish them apart quickly.
Type material examined: COSTA RICA. Alajuela, San Mateo, Higuito [ca 9°56’03.1”N 84°31’27.7”W], ??.??.????, P. Schild (male holotype shannoni USNM, USNMENT 00028640).
Additional material examined: BRAZIL. Roraima, Alto Alegre, FLONA [ca 2°58’09.7”N 61°45’50.3”W], Malaise, 17.v.2018, R. Boldrini (1 female INPA, MMMS0063); Amajari, SESC Tepequém [ca 3°45’20.5”N 61°43’01.0”W], Malaise, 11–15.x.2016, R. Boldrini (1 female INPA, MMMS0064). COLOMBIA. Cartago, Valle del Cauca, 14.xii.2022, 4°44’50.0”N 75°54’41.9”W (1 female, photographic record) [https://www.inaturalist.org/ observations/144478648]. COSTA RICA. San Jose, Est. Santa Helena, Las Nubes [ca 9°59’04.9”N 83°55’08.4”W], 1210m, 5–21.vii.1996, M. Segura (1 male USNM, INBIOCRI002 469598).
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 62-65, DOI: 10.11646/zootaxa.5484.1.1, http://zenodo.org/record/13208985