Orthonevra thompsoni Miranda & Soares, 2024

Miranda, Gil F. G., Soares, Matheus M. M. & Thompson, Christian, 2024, The Neotropical Orthonevra Macquart, 1829 (Diptera: Syrphidae), Zootaxa 5484 (1), pp. 1-78 : 70-73

Orthonevra thompsoni Miranda & Soares sp. nov.

79-1. Thompson 2006: 21 (key reference)

Fig. 38 . Map: Fig. 39

Diagnosis. This species can only be confused with O. sternolobosa , but the wider vitta on the scutellum and the more sinuous vittae on the eyes should confirm the identification of O. thompsoni .

Description. MALE. Head ( Fig. 38a–c ): metallic black, face with slight convexity in profile and ventral 1/4 slightly produced anteriorly as a convexity, strongly regulose except on ventral 1/4, shiny, pile white and not scale-like; with white microtrichose subtriangular macula laterally, positioned immediately ventral to antennal base and separated from it. Antenna dark without metallic reflections, scape paler, post-pedicel slightly pale dorsally; pedicel slightly more than twice the length of the scape, postpedicel oval elongated, slightly longer than the pedicel; pile black. Mala slightly produced apico-ventrally, with weak regulae. Gena shiny, smooth, and with white pile. Frontal triangle regulose except around antennal base, bare except for lateral row of white pile adjacent to eye margin. Vertical triangle isosceles shaped, 2 × longer than eye contiguity, with very short black pile posteriorly; ocellar triangle with a coarse texture, bare. Occiput not visible laterally on dorsal 1/3, homogeneously covered in white microtrichia which extends until dorsal to gena, with one row of very short black pile, bare on ventral 3rd/4, longer and white pile on ventral 1/4. Eyes holoptic; with an anterior straight vitta, and a sub-anterior and middle slightly sinuous vittae, and a medial fascia, anterior vitta connects to the ends of the sub-anterior vitta, and on ventral 1/2 of posterior margin and this margin connecting ventrally with middle vitta.

Thorax ( Fig. 38a, b ): metallic black-green, pile white, very short, appressed and sparsely distributed; scutum with three complete separate dark matte vittae with purple reflections, medial one divided in two on anterior apex, with a short narrow lateral vittate macula posterior to transverse sulcus; notopleuron metallic green; remaining of scutum covered by microsculpture; scutellum with medial matte black vitta extending from base to apex, wider than medial vitta on scutum, pile inconspicuous. Pleuron wholly metallic, smooth on proepimeron, anteroventrally on anepisternum, anteriorly on katepisternum, and on katepimeron, remaining with a coarse texture, with densely distributed white microtrichia on proepisternum, with long white pile on antepronotum, ventral patch on katepisternum, dorsal to the posterior spiracle on the katatergum, and metasternum, with short pile on proepimeron, posterior anepisternum, dorsal patch on katepisternum, and anterior anepimeron, and very short on proepisternum. Calypter white with white marginal pile, ventral lobe with longer marginal pile. Plumule long but with short pile. Halter white.

Legs ( Fig. 38b ): metallic black, except yellow on apex of all femora, medial surface and basal 1/2 of protibia, basal 1/2 of mesotibia, basal 1/3 of metatibia, and first two tarsomeres on all legs; pro and metabasitarsomere swollen. Legs covered with short white pile, metafemur with ventral surface covered in black setulae.

Wing ( Fig. 38a ): with dark short vitta sub-apically on r1, and one vitta sub-apically (from end of R2+3 until posterior end of M1), with four short dark fascia (one in the middle of r2+3, two in the middle of r4+5 and one in the antero-middle of dm), wing apex slightly darker ( Fig. 38a ), stem vein and vein C yellow until crossvein h, mostly microtrichose, bare on small basal area of cell bm and immediately posterior to pseudovein on cup cell; basicosta with sparse appressed pale pile, without prominent setae apically. Alula 2 × the width of cell c.

Abdomen ( Fig. 38a, b ): metallic black-green, terga matte black microtrichose in large medial rectangular area, terminalia wholly metallic, pile sockets as small protuberances, pile black, appressed and very short, white laterally, longer laterally on terga 1 and 2; sterna with white pile; sternum 4 with a large extension on right side that is rounded apically.

Genitalia ( Fig. 38f–i ): epandrium with a shelf-like extension dorsally ( Fig. 38e ); surstylus bent in a 90° in the middle, with slightly convex baso-dorsal portion, curving gently on apex and forming a beak-like short extension on its medial margin, wholly covered in sparse pile but more concentrated on apical 1/2 of the medial margin ( Fig. 38f ); subepandrial sclerite arms higher than wide; cercus elongated, with convex apico-medial 1/2. Hypandrium sub-rectangular, with Y-shaped notch ventrally ( Fig. 38i ); postgonite wide basally, forming a convex lamina, and then tapering towards apex, with a slight small rounded apex, with very few and sparse pile dorso-laterally and densely distributed pile on apico-medial margin; phallus straight with rounded apex (from a ventro-dorsal view), with sub-apical acute extension ventrally, two-pronged medio-ventrally, and a long convexity before the basal tubular process ( Fig. 38h ).

FEMALE. No females recorded.

Length. Body 5.30–5.50mm (n=2), wing 3.90–4.00mm (n=2).

Distribution. Peru ( Fig. 39 ).

Altitudinal range. 350–650m.

Etymology. The specific epithet is a patronym for F. C. Thompson, expert in world Syrphidae and first to notice the initial distinct differences between several species of Neotropical Orthonevra . It should be treated as a noun in the genitive case.

Comments. Similar to O. sternolobosa sp. nov. however, besides the characters pointed out in the key, the phallus is not widened sub-apically and the surstylus doesn’t have a triangular laminate extension dorso-basally.

Type material examined: PERU. Huánuco, Leoncio Prado, Tingo Maria [ca 9°17'48.9"S 75°59'58.0"W], Monson Valley , 2.xii.1954, E. I. Schlinger & E. S. Ross (male holotype thompsoni CASENT, USNMENT 01492705) .

Paratypes examined: PERU. Cusco, Quincemil, Pte La Cigarra , 13º08'27"S 70º23'14"W, 350 m, 01.ix.2012, sweep, J. A. Rafael & R.R. Cavichioli (1 male INPA, MMMS0062 ) .

Figures

FIGURE 38. Orthonevra thompsoni sp. nov., male. a–d. Habitus: a. Dorsal. b. Lateral. c. Head, oblique lateral view. d. Abdomen, apex, ventral view. e–i. Genitalia: e. Epandrium, dorsal view. f. Epandrium, lateral view. g. Epandrium, ventral view. h. Hypandrium, lateral view. i. Hypandrium, ventral view, specimen MMMS0062. Abbreviations: btp: basal tubular process; cerc: cercus; epe: dorsal extension of the epandrium; mfe: middle fascia (eye); mve: medial vitta (eye); pg: postgonite; ph: phallus; sav: sub-anterior vitta; sbe: subepandrial sclerite; scl: scutellum; sur: surstylus; s4 pj: lobular projection of sternum 4; vn: ventral notch of the hypandrium; vt: vertical triangle.

FIGURE 39. Distribution map for Orthonevra argentina (Brèthes, 1922), O. batman sp. nov., O. chilensis Thompson, 1999, O. cthulhu sp. nov., O. quadristriata (Shannon & Aubertin, 1933), O. roseae sp. nov., O. shannoni (Curran, 1926), and O. thompsoni sp. nov.