Orthonevra nebulosa Thompson, 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 : 41-44

Orthonevra nebulosa Thompson & Miranda sp. nov.

98-13 (FCT notes)

Figs 21 and 22 . Map: Fig. 40

Diagnosis. Similar to O. nitidula , but the eye pattern is more complex ( Fig. 21c, f ) in O. nebulosa .

Description. MALE. Head ( Fig. 21d–f ): metallic bluish-green, face convex in profile and ventral ¼ slightly produced anteriorly as a strong convexity, strongly regulose except on medial ventral ½ and lateral ventral 1/3, shiny, with sparse white pile; with white microtrichose subtriangular macula laterally, positioned immediately ventral to antennal base and separated from it. Antenna yellow, except post-pedicel dark with pale base; pedicel 2.5 × the length of the scape, postpedicel oval elongated, 1.25 × the length of the pedicel. Mala slightly produced apico-ventrally, with weak regulae. Gena shiny, with weak microsculpture, with white pile. Frontal triangle regulose except on lunule, with median longitudinal crease from eye contiguity until dorsal to lunule, with erect, white pile restricted to a row on the lateral margin adjacent to eye margin. Vertical triangle isosceles-shaped, 1.5 × longer than eye contiguity, with erect white pile restricted to ocellar triangle; ocellar triangle with a rough texture, taking up 2/3 of the vertex. Occiput not visible laterally on dorsal ½, ventral ½ homogeneously covered in white microtrichia which extends until dorsal to gena, with a row of short black pile on dorsal ½, becoming inconspicuous on ventral 3 rd /4 and long and white ventrally. Eyes holoptic; with two strongly sinuous vittae anteriorly, merging in several points, and one almost straight sub-posterior vitta which connects to middle vitta dorsally and to middle vitta and posterior margin ventrally, and a medial fascia, pattern forms a circle dorso-anteriorly and two others posteriorly dorsal and ventral to fascia, eyes darker on anterior margin between the ends of the anterior vitta, and on ventral ½ of the posterior margin.

Thorax ( Fig. 21d, e ): metallic black-green, pile short, erect, white and densely distributed; scutum with four dark matte vittae, all tapering anteriorly, and with a short narrow lateral vittate macula posterior to transverse sulcus; scutellum metallic-green, with apical margin flattened, with short, erect, white and sparse pile, more concentrated laterally. Pleuron smooth on proepimeron, anteriorly on anepisternum and katepisternum, and katepimeron, remaining with a coarse texture, with long white pile on antepronotum, anteriorly on proepimeron, ventral patch on katepisternum, and dorsal to the posterior spiracle on the katatergum, with short pile on posterior anepisternum, dorsal patch on katepisternum, anterior anepimeron, and metasternum, and very short on proepisternum. Calypter white with long marginal pile on ventral lobe. Plumule white. Halter yellow.

Legs ( Fig.21e ): metallic black, except yellow on first two pro- and mesotarsomeres and three metatarsomeres; pro and metabasitarsomere swollen. Legs covered with short appressed white pile, apex of mesotibia and mesotarsomeres with ventral black setulae, metafemur with ventral surface covered in black setulae.

Wing ( Fig. 21d, e ): mostly hyaline, with dark narrow sub-apical vitta (from end of R2+3 until posterior end of M1), one vitta sub-apically on r1, and faintly on dm-m, with a dark spot on the apex of cell r2+3, also with two small dark fasciae inside r4+5 and one inside dm ( Fig. 21e ), stem vein pale until crossvein h and C only at base (not reaching h), mostly microtrichose, bare on small middle area of cell r, bm and basally posterior to pseudovein on cua; basicosta with dense appressed pale to dark pile, with at least one more prominent black setae apically. Alula 2 × the width of cell c.

Abdomen ( Fig. 21d, e ): metallic black with some green reflections, terga matte microtrichose in large medial rectangular area, pile sockets as small protuberances, pile black, appressed and very short, white laterally on terga 1 and 2, longer baso-laterally on tergum 2; sterna with white appressed pile; sternum 4 slightly extended on right side.

Genitalia ( Fig. 22c–f ): surstylus bent in a right angle at basal 1/3, base slightly wider, with a medial oval fenestra, rest of surstylus directed medially, apex ovulate but with short acute ventral projection, with short pile sparsely distributed ( Fig. 22c ); cercus sub-triangular, dorsal margin straight. Hypandrium ventral notch T-shaped ( Fig. 22d ); postgonites laminate, oval and wide, with densely distributed pile on most of the dorso-lateral surface; phallus short, with three ventral dens (when seen in profile), basal 2/3 flanked on both sides by ventral carina, basal tubular process arises from dorsal surface of phallus, but under the phallapodeme, curving around the base and ending at the ventral base, between the base of the lateral carinae ( Fig. 22f ).

FEMALE ( Figs 21a–c , 22a, b ). Like male except: face convexity more gentle; frons regulose except around antennal base, with median longitudinal crease from ocellar triangle until middle of frons, with sparse, short, erect, white pile, except bare dorsal to lunule, and with a ventro-lateral row of white pile adjacent to eye margin; vertex with short, erect, white pile; ocellar triangle with a coarse texture, with short, erect, white pile; eyes with two strongly sinuous vittae and one almost straight sub-posterior vitta which connects to middle vitta dorsally and to posterior margin ventrally, middle vitta forms a loop on dorsal and ventral halves, and a medial fascia ( Fig. 21c ). Genitalia ( Fig. 22a, b ): Tergum and sternum 7 as pair of sclerotized rectangular areas, with a few pile on anterior margin, much longer on sternum. Tergum 8 as a pair of small, heavy sclerotized, rectangular plates, bare. Sternum 8 more voluminous than tergum, with a U-shaped sclerotized area and an apico-medial concavity, with large apical depression on each side, wholly pilose. Sternum 9 as half-oval, lightly sclerotized, with a long heavily sclerotized internal tube connecting the genital opening to the three spermathecal ducts. Epiproct lightly sclerotized, convex apical margin, without apodemes, pile restricted to pair of lateral patches. Cercus oval, pilose, positioned apically to epiproct. Hypoproct as a pentagonal sclerotized area, narrowed sub-apically, pilose.

Length. Body 4.74–5.05mm (n=3), wing 3.64–3.96mm (n=3); female 5.16mm (n=1), wing 3.98mm (n=1).

Distribution. Costa Rica and Mexico ( Fig. 40 ).

Altitudinal range. 540–750m.

Etymology. The specific epithet derives from the Latin ‘nebula’ (fog, mist, cloud) and alludes to the swirling shapes of the eye markings, similar in shape to the star-forming regions of space. The specific epithet should be treated as an adjective.

Comments. Orthonevra nebulosa sp. nov. and O. nitidula are the only species that have a sub-posterior vitta on the eye, beside the extra vitta on the scutum of O. nitidula , O. nebulosa sp. nov. can be distinguished by the more complex eye pattern (anterior vittae merge in different points forming loops). The dorsal origin and the strong curving of the basal tubular process of the phallus is very distinct in this species ( Fig. 22f ); some species (e.g. O. neotropica ) curve in a similar manner but not as strongly.

Type material examined: MEXICO. Chiapas, Cacahoatan [ca 15°00’22.6”N 92°10’13.0”W], 7km N, 22.iv.1983, W. N. Mathis (male holotype nebulosa USNM, USNMENT 00028635) .

Paratypes examined: COSTA RICA. Guanacaste, ACG, Sector Orosí [ca 9°47’01.5”N 83°51’14.4”W], Send Maritza-Cacao , 750m, 17.ii.1996, S. Marshall (1 male USNM, INBIOCRI002 515857); Estacion Maritza [ca 10°57’24.9”N 85°29’42.9”W], 600m, 13.ii.1996, S. Marshall (1 male DEBU, INBIOCRI002 239978). MEXICO. Chiapas, Simojovel [ca 17°08’29.5”N 92°42’23.8”W], 9-10.vi.1969, H.J. Teskey, (1 female CNC, CNC _ Diptera 171120) .

Figures

FIGURE 21. Orthonevra nebulosa sp. nov. a–c. Female: a. Habitus dorsal. b. Habitus lateral. c. Head, oblique latera viewl. d–f. Male: d. Habitus dorsal. e. Habitus lateral. f. Head, oblique lateral view. Abbreviations: fm: fasciate maculae; mfe: middle fascia (eye); mvs: middle vitta (scutum); spv: sub-posterior vitta.

FIGURE 22. Orthonevra nebulosa sp. nov., genitalia. a. Female, dorsal view. b. Female, ventral view. c–f. Male: c. Epandrium, dorsal view (surstyli slightly detached). d. Hypandrium, ventral view. e. Hypandrium, lateral view. f. Phallus, lateral view. Abbreviations: cerc: cercus; epi: epiproct; fn: fenestra; hypo: hypoproct; pg: postgonite; sur: surstylus; s8: sternum 8; s8d: apicolateral depression of sternum 8; vn: ventral notch of the hypandrium.

FIGURE 40. Distribution map for Orthonevra gewgaw (Hull, 1941), O. gouletmasnerorum sp. nov., O. minuosetulata sp. nov., O, nebulosa sp. nov., O. neiae sp. nov., O. neotropica (Shannon, 1925), and O. theta sp. nov.