Vitaleucopis scopulus, Gaimari, 2020

Gaimari, Stephen D., 2020, Two new genera of Nearctic Chamaemyiidae (Diptera: Lauxanioidea) associated with Cinara aphids (Hemiptera: Aphididae) on Pinus, Zootaxa 4852 (1), pp. 61-82 : 78-82

Vitaleucopis scopulus sp. nov.

urn:lsid:zoobank.org:act:824EC8DB-56C6-4A84-A43D-64EB58964A15

( Figs 35–45 )

Etymology. From the masculine Latin noun “ scopulus ” (a descendant term from the Ancient Greek term σκόπελος meaning lookout place) meaning projecting rock, observation point, or cliff, referring to the frons projecting well over the antennae and descending face in the male of this species; a noun in apposition.

Diagnosis (male only). The distance from the vertex to the anterior tip of the frons is 1.7 X the width of the frons at the level of the anterior ocellus, and the frons is subequal in length and width. At the anterolateral corner of the frons, there is a tight lateroclinate cluster of 2–4 elongated setae (length 1.3 X the distance between inner vertical setae) appearing as one very thick seta. On the legs, the femora are entirely dark grey pruinose. The pleuron is concolorous with the uniformly dark grey pruinose scutum. The scutum has dorsocentral setae 0+3 or 0+4, with the posterior seta 2.5 X longer than the next anterior one; the anterior notopleural seta is nearly 2 X longer than the posterior one. Pregenital segments and genitalia: syntergite 7+8 has a median strip of reduced sclerotization, appearing split into two halves; the surstylar lobe is fully articulated with and separate from the epandrium; the phallus from ventral view is awl-shaped, with the middle part parallel-sided, and the tip abruptly curved and sharp.

Description. Adults, ♂ (♀ unknown). Body ( Fig. 35 ) length 2.4 mm.

Head ( Figs 35–38 ). 1.7 X higher than long; 1.3 X wider than high; mostly dark silvery grey with exceptions following. Vertex with outer vertical seta longer than inner one by 1.6 X; distance from vertex to anterior tip of frons 1.7 X width of frons at level of anterior ocellus. Postocellar setae absent. Ocellar triangle (probably sexually dimorphic) elongate, only slightly tapering to anterior margin of frons, slightly raised and distinct from fronto-orbital plate, anteriorly ending in dense patch of short white setulae on distinct whitish spot and extending over antennal bases; ocelli in equilateral triangle, on small raised tubercle, with ocelli placed well anterior to vertex; setulose within and in front of triangle, and behind posterior ocelli. Ocellar setae absent. Eye 1.1 X higher than long; height 6.0 X genal height. Frons with reddish-brown vitta along edge of ocellar triangle; width and length subequal; with lateral edges only slightly diverging anteriorly, 1.2 X wider at level of lunule than at level of anterior ocellus. Mid frontal vitta depressed; oriented downward below tip of ocellar triangle, and meeting lunule at sharp angle. Fronto-orbital area lacking fronto-orbital setae; with scattered setulae and an irregular row of setulae oriented slightly lateroclinate, with distinct cluster of 4–5 elongated (length 1.3 X distance between inner vertical setae), yellowish lateroclinate setae (appearing like 1 very thick seta) at anterolateral corner. Lunule silvery grey pruinose above antennae, strongly depressed below mid frontal vitta; narrowly arched, height 0.4 X frons length; with 2 small, fine setulae. Antenna entirely black; bases separated by small carina, with area between antennal bases shiny black, lacking pruinosity; 1st flagellomere short, rounded, covered with short thick white setulae; arista with distal segment 3.3 X longer than basal. Face, parafacial and gena silvery grey pruinose. Face strongly receding. Parafacial narrow. Gena with one strong genal seta, lacking additional setulae in front and behind. Clypeus black; small, barely exposed. Palpus black; spatulate; densely setulose. Mouthparts very small and held within oral cavity above palpi; prementum and labellum dark.

Thorax ( Figs 35–36 ). Scutum uniformly dark silvery grey pruinose; 1.2 X longer than wide; 3.8 X scutellar length; setulose dorsally (bounded laterally by supra-alar line); dorsocentral vittae absent. Prescutellum present. Scutellum concolorous with scutum; 1.7 X wider than long. Pleuron concolorous with scutum. Chaetotaxy: 0+3 (0+4 on one side) dorsocentral setae, posterior seta 2.5 X longer than next anterior one, with next anterior one(s) slightly smaller; one postpronotal seta, with several smaller setulae; two notopleural setae, in anterior and posterior corners, anterior one 1.9 X longer than posterior one; one pre- and one postsutural supra-alar seta; two postalar setae; prescutellar acrostichal seta absent; proepisternum, anepisternum and anepimeron lacking setae; one strong katepisternal seta along upper edge, with 3 small setulae in row anterior to seta; two pairs scutellar setae, subequal in length, posterior pair subparallel but bowed out along length. Legs. Brownish, with femora and tibiae dark grey pruinose except mid and hind legs with femora yellow distally, tibiae yellow apically, and basotarsomeres and second tarsomeres yellow. Wing. Length 2.1 mm; 2.3 X longer than high. Hyaline, with veins brown. Veins R 2+3, R 4+5 and M 1 subparallel in distal half of wing. Crossvein r-m located slightly basad of halfway point of wing length, and at about 2/3 point of cell dm length. Vein Cu extends to wing margin; apical section 1.2 X longer than crossvein dm-cu. Halter stalk brown, knob yellow.

Abdomen ( Fig. 39 ). Tergites shiny black, with light covering of silvery pruinosity, except bronzy pruinosity on the dorsal part of syntergite 1+2 and tergite 3; uniformly setulose, except setulae slightly enlarged along posterior margin, longest laterally. Syntergite 1+2 and tergite 3 of ♂ each with patch of microtrichiae on lateral edge (cf. fig. 2 of Gaimari et al. 2008). Sternites silvery grey pruinose; sternite 2 nearly 2 X wider than long, 1.2 X wider than sternite 3; sternite 3 1.7 X wider than long, and 1.7 X wider than sternite 4; sternites 4 and 5 each slightly wider than long, with sternite 5 slightly larger. Pregenital segments of male. Tergite and sternite 6 absent. Syntergosternite 7+8 narrow, 0.6 X length of preceding tergite, with median strip lacking sclerotization (appears split into two halves), tapering laterally, with longest setae along posterior margin; sternite 7 apparently absent.

Male genitalia ( Figs 40–45 ). Epandrium slightly convex posteriorly, with 9–11 setae along posterior part of each side; separated and articulating with surstylar lobe; surstylus very long (as long as width of epandrium) and with large flat lobe medially from articulation with epandrium, flattened throughout length, strongly incurved, with sharpened ventral edge, and distally with tiny setulae. Cercus large, narrowing to point distally, with several long and numerous short setulae. Hypandrium in dorsal view about 1.2 X longer than wide, with anterior arms very thick to point of articulation with pregonite, becoming abruptly thin posteriorly, anterior margin emarginate; in profile, abruptly angled with “chicken-leg” shape, evenly wide in posterior half, and abruptly narrower anteriorly. Pregonite articulating with medial portion of wide part of hypandrium, such that bases are close together; parallel-sided, with blunt tip; slightly curved in lateral view; dorsally setulose. Postgonite long (shorter than pregonite), tapering to small outcurved tip; bare. Phallapodeme slightly longer than high from lateral view, with anterior edge evenly convex, with ventral edge evenly concave; in dorsal view, “chess-pawn”-shaped, about 3 X longer than wide, widening into tear-drop-shaped anterior and wide posterior ends. Phallus from ventral view awl-shaped, with bulbous basal half, tapering through middle, then becoming bulbous and tapering evenly to sharp tip, evenly sclerotized through middle, with area near tip open; length about 3 X width of bulbous base; from lateral view undulating, narrow throughout, with anterior part widest, tapering posteriorly and with abrupt curve at tip.

Immatures. Unknown.

Type material. Holotype ♂ (double mounted on minuten, very good condition), deposited in CSCA, with the following labels: “1958, aborted sugar pine cones, Orleans, Trinity Co., coll. Sept-1958, emerg. III–27–59” [note, Orleans is in Humboldt County , California] / “SDG dissection, 1388 ♂ ” / “ HOLOTYPUS ♂ Vitaleucopis scopulus Gaimari ” (red label).

Distribution. Known from the western United States (northern California).

Biology. As presented on the collection label, it seems likely that “aborted sugar pine cones” implies predation on adelgids attacking sugar pine, Pinus lambertiana Douglas , since they sometimes infest areas at the bases of new cones and can stunt or abort their development. The fly could have pupariated on the cone after having fed upon associated adelgids or Cinara aphids.

Remarks. The male genitalia do not appear substantially different from Vitaleucopis astonea except for the surstylus being fully separated and articulated with the epandrium in the new species. Several external characters can also be used to differentiate them, including the different number of dorsocentral setae (0+3) and the conformation of the frons (the length of the head in dorsal view, from the vertex to the tip of the frons is 1.7 X the width of the frons at the level of the anterior ocellus; the width of the frons at the level of the anterior ocellus is subequal to the length of the frons from the anterior ocellus to the tip) and of syntergite 7+8 (with a median strip lacking sclerotization, appearing split into two halves).

Figures

FIGURES 35–39. Vitaleucopis scopulus sp. nov., holotype ♂. 35. Habitus, lateral view. 36. Head and thorax, dorsal view. 37. Head, dorsal view. 38. Head, dorsal oblique view. 39. Abdomen, dorsal view.

FIGURES 40–45. Vitaleucopis scopulus sp. nov., holotype ♂, genitalia. 40. Epandrial complex, lateral view. 41. Epandrial complex, posterior view. 42. Epandrial complex, posterior view tilted ventrally (showing dorsum of epandrium). 43. Hypandrial complex, dorsal view (phallus reflexed downward). 44. Phallic complex, lateral view. 45. Phallus, dorsal view. Abbreviations: c = cercus, e = epandrium, h = hypandrium, pa = phallapodeme, pg = postgonite, ph = phallus, pr = pregonite, ss = surstylus. Scale bar = 0.1 mm.