Vitaleucopis astonea (McAlpine), 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 : 68-72

Vitaleucopis astonea (McAlpine)

( Figs 12–19 )

Leucopis (Leucopis) astonea McAlpine, 1977: 14 . Type locality: Canada. British Columbia: Vaseaux Lake , near Oliver. Holotype ♂, CNC.

Diagnosis. In males, the distance from the vertex to the anterior tip of the frons is 1.3 X the width of the frons at the level of the anterior ocellus, and the frons is 1.4 X wider than long. At the anterolateral corner of the frons, there is a tight lateroclinate cluster of 4–5 elongated setae (as long as the distance between inner vertical setae) appearing as one very thick seta. On the legs, the femora are dark grey pruinose, except the distal tip is yellow. The pleuron is silvery grey pruinose and lighter in color than the scutum. The scutum has dorsocentral setae 0+2, with the posterior seta at most 2 X longer than the anterior one; the anterior notopleural seta is 1.5 X longer than the posterior one. In the male pregenital segments and genitalia: syntergite 7+8 is entire, lacking a median strip; the surstylar lobe is articulated, but partly fused, with 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, ♂, ♀. Body ( Fig. 12 ) length 2.3–2.5 mm (♂, 2.5 mm; ♀, 2.3–2.5 mm).

Head ( Figs 12–16 ). 1.4–1.5 X higher than long; 1.3–1.4 X wider than high; mostly dark or silvery grey with exceptions following. Vertex with outer vertical seta longer than inner one by 1.7–2.0 X; in ♂, distance from vertex to anterior tip of frons 1.3 X width of frons at level of anterior ocellus. Postocellar setae absent. Ocellar triangle sexually dimorphic; in ♂, 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 yellow spot and extending over antennal bases; in ♀, extending most of distance of frons, not raised, distinguishable from fronto-orbital plate by only slight color difference, anteriorly lacking patch of distinct setulae, lacking yellow spot, and not extending over antennal bases, but instead abruptly curving downward into plane with lunule; ocelli in equilateral triangle, on small raised tubercle, with ocelli placed well anterior to vertex; setulose within triangle and behind posterior ocelli. Ocellar setae absent. Eye 1.1–1.2 X higher than long; height 4.3–5.2 X genal height. Frons with slightly darkened vitta along edge of ocellar triangle in ♂, without such vitta in ♀; 1.4 X wider than long in ♂, 1.8–1.9 X in ♀; with lateral edges only slightly diverging anteriorly, 1.0–1.2 X wider at level of lunule than at level of anterior ocellus. Mid frontal vitta depressed in ♂, not depressed in ♀; oriented downward below tip of ocellar triangle, and meeting lunule at sharp angle in ♂ and in same vertical plane with lunule in ♀. Fronto-orbital area lacking fronto-orbital setae; in ♂ with row of 6–7 setulae oriented slightly lateroclinate and with distinct cluster of 4–5 elongated (as long as distance between inner vertical setae), yellowish lateroclinate setae (appearing like 1 very thick seta) at anterolateral corners, and in ♀ with 10 or more setulae and with no cluster of elongated setulae anterolaterally. Lunule silvery grey pruinose above antennae, strongly depressed below mid frontal vitta in ♂, in same plane with mid frontal vitta in ♀; narrowly arched, height 0.3–0.4 X frons length; with 0–2 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 3.6–4.2 X longer than basal. Face, parafacial and gena silvery grey pruinose. Face strongly receding. Parafacial narrow. Gena with one strong genal seta in addition to several setulae in front and behind. Clypeus black; small, barely exposed. Palpus black; spatulate; densely setulose, larger in ♀. Mouthparts very small and held within oral cavity above palpi; prementum and labellum dark.

Thorax ( Figs 12–13 ). Scutum uniformly dark silvery grey pruinose; 1.1–1.2 X longer than wide; 3.6–3.9 X scutellar length; setulose dorsally (bounded laterally by supra-alar line); dorsocentral vittae absent. Prescutellum present. Scutellum concolorous with scutum; 1.5–1.7 X wider than long. Pleuron silvery grey pruinose, lighter than scutum. Chaetotaxy: 0+2 dorsocentral setae, posterior seta 1.7–2.0 X longer than anterior one; one postpronotal seta, with several smaller setulae; two notopleural setae, in anterior and posterior corners, anterior one 1.5 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 2–4 small setulae in row anterior to seta; two pairs scutellar setae, subequal in length, posterior pair subparallel but bowed out along length. Legs. Dark brown, with femora dark grey pruinose except for distal tip yellow, and tibiae dark grey pruinose, and with basotarsomeres and second tarsomeres (and sometimes third tarsomeres) yellow. Wing. Length 2.2–2.4 mm (♂, 2.3 mm; ♀, 2.2–2.4 mm); 2.6–2.8 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 3/4 point of cell dm length. Vein Cu extends to wing margin; apical section 1.4–1.5 X longer than crossvein dm-cu. Halter stalk brown, knob yellow.

Abdomen ( Figs 17 , 19 ). 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 1 divided medially; sternite 2 divided transversely with anterior part a narrow strip and the posterior part 2 X wider than long and 1.2–1.4 X wider than sternite 3; sternite 3 in ♂ 1.7 X wider than long and 1.8 X wider than sternite 4, in ♀ slightly wider than long, slightly tapering posteriorly, subequal in size to sternite 4; sternites 4 and 5 each slightly wider than long, with sternite 5 slightly wider and slightly shorter. Pregenital segments of male. Tergite 6 absent, condition of sternites 6 and 7 not visible. Syntergosternite 7+8 a narrow undivided strip, tapering laterally, with longest setae along posterior margin.

Male genitalia ( Fig. 18 ). Epandrium slightly convex posteriorly, with 7–8 setae along posterior part of each side; extending into surstylar lobe (whether entirely separate or partly fused to epandrium not evident without dissection); 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 not visible. Pregonite parallel-sided, with blunt tip; slightly curved in lateral view; dorsally setulose. Postgonite long (shorter than pregonite), tapering to small outcurved tip; bare. Phallapodeme not visible. Phallus from ventral view awl-shaped, with bulbous basal half, parallel-sided in middle, then tapering evenly to sharp tip, evenly sclerotized through middle, with area near tip open; length 3 X width of bulbous base; from lateral view slightly curved, narrow throughout, with anterior part widest, with dorsal lobe small, and tapering posteriorly with abrupt curve at tip.

Female terminalia ( Fig. 19 ). Tergite 6 4.3 X wider than length through middle, length through middle 0.4 X length of tergite 5, anterior and posterior margins emarginated, with darkly sclerotized transverse strip; sternite 6 enlarged, emarginate anteriorly and posteriorly, with width 0.8 X width of tergite 6, 2.4 X wider than long, and 2.5 X wider than sternite 5, with long setulae along posterior edge; tergite 7 entirely membranous, but with corresponding patch of long setulae on membrane; sternite 7 small (0.7 X length and half width of sternite 6), nearly 2 X wider than long, with deeply emarginated posterior margin, with long setulae on membrane posterior to sternite; tergite 8 subsquare, slightly narrower than sternite 7, lightly sclerotized, with long setulae (as long as setulae of cercus) along posterior margin; sternite 8 absent, entirely membranous, with corresponding patch of long setulae. Hypoproct tapering evenly to rounded tip. Epiproct subtriangular, with normal cercus bearing uniformly short setulae. Internally, spermathecae 2+2, round.

Immatures. Unknown.

Type material. Holotype ♂ (glued to side of pin, very good condition), deposited in CNC, with the following labels: “Vaseaux L., Oliver, B.C., 14.V.1959, R. E. Leech ” / “ IDEMA illustration” / “ HOLOTYPE ♂, Leucopis , astonea, McAlpine, No. ” (red label) . Paratypes (both labeled “ IDEMA illustration.” CANADA. BRITISH COLUMBIA. Oliver , Vaseaux Lake, 14.v.1959, coll. R. E. Leech [same data as holotype] (1 ♀ (labeled “ Allotype ”), 1 ♀ (labeled “ Paratype ”, with dissected abdomen in microvial beneath specimen), CNC) .

Distribution. Known from southwestern Canada (British Columbia).

Biology. Unknown.

Remarks. Male genitalia are a critical component of chamaemyiid identification. However, because there was no ambiguity as to the identity of this species relative to the other two species of this genus, the male abdomen was not dissected. Most genitalic characteristics (except the hypandrium, phallapodeme, and part of the basiphallus) are visible in the undissected state, so this author believed that because it is the sole male known for the species, it was more important to leave the specimen in its pristine condition, where external characteristics of the abdomen can also be studied. By the visible genitalic characteristics, this species differs only subtly from Vitaleucopis scopulus , in that Vitaleucopis astonea has a surstylus that is partly fused to the epandrium while it is fully articulated and separate in Vitaleucopis scopulus . In addition, several external characters can be used to differentiate those species, including the different number of dorsocentral setae (0+2) and the conformation of the frons (the length of the head from dorsal view, from the vertex to the tip of the frons is 1.3 X the width of the frons at the level of the anterior ocellus, and the width of the frons at the level of the anterior ocellus is 1.4 X the length of the frons from the anterior ocellus to the tip) and of syntergite 7+8 (entire and undivided). If the diversity of this genus becomes an issue, the specimen will still be available for dissection at a later date if necessary.

Figures

FIGURES 12–17. Vitaleucopis astonea (McAlpine), holotype ♂ (except 16, paratype ♀). 12. Habitus, lateral view. 13. Head and thorax, dorsal view. 14. Head, dorsal view. 15. Head, dorsal oblique view. 16. Head (paratype ♀), dorsal oblique view. 17. Abdomen, dorsal view.

FIGURES 18–19. Vitaleucopis astonea (McAlpine). 18. Holotype ♂, genitalia in situ, ventrolateral view. 19. Paratype ♀, ster- nites 1–7, ventral view. Abbreviations: c = cercus, e = epandrium, pg = postgonite, ph = phallus, pr = pregonite, ss = surstylus, s6 = sternite 6, s7 = sternite 7. Scale bar = 0.1 mm.