Orthonevra minuosetulata 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 : 40-41

Orthonevra minuosetulata Thompson & Miranda sp. nov.

98-3. Thompson 2006: 22 (key reference).

Fig. 20 . Map: Fig. 40

Diagnosis. The facial microtrichose maculae greatly distanced from the antennal insertions, and only having the first two metatarsomeres pale, distinguishes this species from the similar O. neiae .

Diagnosis. MALE. Head ( Fig. 20a–c ): metallic blue, face with slight convexity in profile and ventral 1/4 slightly produced anteriorly as a strong convexity, regulose except for smooth ventral 1/3, shiny, pile white, short, not scale-like and very sparse; with white microtrichose subtriangular macula laterally, positioned immediately ventral do antennal base and widely separated (twice the macula’s width) from it. Antenna yellowish brown, scape and pedicel slightly darker and with slight metallic reflections dorsally, post-pedicel paler on basal 1/2; pedicel twice the length of the scape, postpedicel oval elongated, 1.5 × the length of the pedicel. Mala produced apico-ventrally, smooth. Gena shiny, smooth, and with white pile. Frontal triangle shiny, ventral 1/2 mostly smooth and slightly expanded, dorsal 1/2 rugose, bare except for distinct erect pile anterior to eye contiguity and following the eye margin. Vertical triangle isosceles triangle-shaped, around 3 × as long as eye contiguity, metallic green, mostly bare with some inconspicuous black pile posteriorly; ocellar triangle equilateral, black, smooth, and bare. Occiput not visible laterally on dorsal 1/3, ventral 2/3 homogeneously covered in white microtrichia which extends until dorsal to gena, very inconspicuous pile on dorsal 1/3, with a few sparse, long and white, pile on ventral 1/4. Eyes holoptic; with a sub-anterior slightly sinuous vitta, and a straight middle vitta, and a small fasciate macula anteromedially, eyes darker on ventral 1/2 of posterior margin.

Thorax ( Fig. 20a, b ): metallic green, pile white, very short, appressed and sparsely distributed, bare on matte areas; scutum with three complete dark matte vittae fused posteriorly by a narrow matte fascia, medial one wide and wider posteriorly, sub-medial pair narrower and tapering posteriorly, vittae with purple reflections, with a short narrow lateral vittate macula posterior to transverse sulcus; scutellum metallic green with medial matte black vitta extending from base to apex, as wide as medial vitta on scutum, bare, only with microtrichia. Pleuron mostly with sparse microtrichia, with short white pile on proepisternum (barely visible), anterior anepimeron, on ventral patch on katepisternum, and on katatergum. Calypter white with white marginal pile, ventral lobe with longer marginal pile. Plumule yellowish. Halter yellowish.

Legs ( Fig. 20b ): metallic green, except pale brown trochanters, and yellow apex of all femora, whole protibia, basal 1/2 of mesotibia, basal 1/3 of metatibia, and first two tarsomeres, last three tarsomeres dark; pro and metabasitarsomere swollen. Legs covered with short yellow pile, mesoleg with long black setulae apico-ventrally on tibia and ventrally on tarsus, metafemur apical 1/2 with ventral surface with a few black setulae.

Wing ( Fig. 20a, b ): hyaline, with dark vitta sub-apically (from the end of R2+3 until posterior end of M1), weaker sub-apically in r1, dark on apex, and with fasciate maculae in r2+3, r4+5 (two), and dm, stem vein and vein C orange until crossvein h, wing bare on most of bm and baso-anteriorly on cua; basicosta with sparse appressed white pile, without prominent setae apically. Alula 2 × the width of cell c.

Abdomen ( Fig. 20a, b ): metallic blue-green, terga matte black on large medial rectangular area, terminalia wholly metallic, pile sockets as small protuberances, pile white, erect and inconspicuous, much longer and distinct baso-laterally on tergum 2; sterna metallic blue, with white pile; sternum 4 with right side slightly extended.

Genitalia ( Fig. 20d–f ): surstylus overall crooked, bent in a right angle at basal 1/4, base slightly wider, apex curving and directed medially, with short pile sparsely distributed, left surstylus with a medial lamina ( Fig. 20d ); cercus pickaxe-shaped. Hypandrium compressed medially, with ventral opening forming a small pocket for the base of the phallus, and flanked by short laminae ( Fig. 20e, f ); postgonites wide and tapering apically, with sparse pile baso-laterally; phallus mostly straight but apex gently curving ventrally, with two concavities at base (anterior to basal tubular process), basal tubular process short ( Fig. 20e ).

FEMALE. No females recorded.

Length. Body 4.57mm (n=1), wing 3.06mm (n=1).

Distribution. Peru ( Fig. 40 ).

Altitudinal range. 250m.

Etymology. The specific epithet is a combination of the Latin words ‘minuo’ (lessen, reduce, lower) + ‘setula’ (small bristle) and alludes to the reduced number of ventral setulae on the metafemur. It should be treated as a noun in apposition.

Comments. Very close to O. neiae sp. nov. in terms of external morphology, however, besides the distinct genitalia, major differences are pointed out in the key. No pile was observed on the antepronota, a unique condition among the material studied. Since no female was recorded, it remains unknown if it shares the unique condition of tergum 5 as seen in O. neiae sp. nov.

Type material examined: PERU. Madre de Dios, Manu, Rio Manu, Pakitza , 12 7’S 70 58’W, 250 m, 9– 23.ix.1988, W. N. Mathis (male holotype minuosetulata USNM, USNMENT 01492706) .

Figures

FIGURE 20. Orthonevra minuosetulata sp. nov., male. a–d. Habitus: a. Dorsal. b. Lateral. c. Head, oblique lateral view. d–f. Genitalia: d. Epandrium, ventral view. e. Hypandrium, lateral view. f. Hypandrium, ventral view. Abbreviations: btp: basal tubular process; cerc: cercus; lmm: lateral microtrichose sub-triangular macula; mls: medial lamina of the surstylus; pct: hypandrium ventral notch pocket; pg: postgonite; ph: phallus; sbe: subepandrial sclerite; sur: surstylus; trm: tarsomere.

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.