Chamaethrix necopina, 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 : 62-67

Chamaethrix necopina sp. nov.

urn:lsid:zoobank.org:act:CEE1D15E-AE26-4807-B7F2-A3436609F6F1

( Figs 1–10 )

Etymology. From Latin, necopina , meaning “unexpected”, indicating the author’s surprise at finding this interesting taxon.

Diagnosis. The body is compact and stout. Postocellar setae are absent, but ocellar setae are tiny, widely separated and proclinate. The frons is flat, and descends at an angle from the vertex, with the lunule above the antennae in the same angled plane. The fronto-orbital area has 5–6 evenly spaced setae along the eye margin. The lunule is high and setulose, curved back to be in the same plane with the frons. The antennae are yellow, except for a darkened spot on the 1st flagellomere anterobasally to the arista and the darkened distal section of the arista. The palpus, prementum and labellum are yellow, with the palpus being spatulate. The scutum is silvery grey pruinose, lacking dorsocentral vittae, and with 3–4 dorsocentral setae in the posterior half of the scutum. Prescutellar setae are absent. The abdominal tergites are mostly silvery grey, but tergite 3 has a pair of darkened pruinose spots. In the male genitalia, the postgonite is absent.

Description. Adults, ♂, ♀. Body ( Fig. 1 ) length 2.0– 2.4 mm (♂, 2.0– 2.2 mm; ♀, 2.4 mm); mostly concolorous silvery grey pruinose.

Head ( Figs 1–3 ). 1.2–1.4 X higher than long; 1.3–1.4 X wider than high. Vertex with outer vertical seta slightly longer than inner one. Postocellar setae absent. Ocellar triangle equilateral, slightly raised, placed slightly anterior to vertex; lacking setulae. Ocellar setae tiny, proclinate; separated by distance equal to distance between posterior ocelli; originating beside anterior ocellus. Eye 1.2–1.3 X higher than long; height 2.1–2.4 X genal height. Frons 1.5–1.7 X wider than long; with lateral edges only slightly diverging anteriorly, 1.1–1.2 X wider at level of lunule than at level of anterior ocellus; with small, fine, reclinate setulae medially; descending from vertex at angle, with lunule curved up into same plane. Mid frontal vitta slightly depressed, darker grey pruinose than fronto-orbital area and ocellar triangle. Fronto-orbital area with 5–6 evenly spaced setae along eye margin, with each seta shorter than outer vertical seta. Lunule arched, height 0.5–0.6 X frons length; sloping abruptly into plane of frons above antennal base; with small, fine, proclinate setulae in upper part. Antenna yellow except 1st flagellomere with darkened spot anterobasally to arista and distal segment of arista dark; separated by width of antennal socket; 1st flagellomere short, rounded; arista with distal segment 2.8–3.2 X longer than basal. Face and parafacial undifferentiated, whitish pruinose, receding, with deep antennal grooves. Gena whitish pruinose with one strong genal seta in addition to several setulae behind, receding below eye. Clypeus small, exposed. Palpus yellow, spatulate; with several scattered tiny setulae and one slightly larger distal setula. Prementum and labellum yellow.

Thorax ( Figs 1–2 ). Scutum 1.2–1.3 X longer than wide; 3.5–3.9 X scutellar length; setulose dorsally (bounded laterally by supra-alar line); dorsocentral vittae absent; color varies to slightly bronzy grey. Prescutellum present. Scutellum 1.5–1.7 X wider than long; color varies to slightly bronzy grey. Chaetotaxy: lacking presutural dorsocentral setae, with 3 or 4 postsutural dorsocentral setae, posterior seta longest, with size decreasing for each one anteriorly, and with anterior-most seta sometimes scarcely distinguishable from scutal setulae; one postpronotal seta, with several smaller setulae; two notopleural setae, in anterior and posterior corners, posterior one slightly smaller; 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 2–3 small setulae anterior to seta; two pairs scutellar setae, subequal in length, posterior pair subparallel but bowed out along length. Legs. Femora greyish pruinose, with distal tip yellow; forefemur thickened. Tibiae yellow, with sparse silvery pruinosity. Tarsi yellow, with distal part of tarsomere 5 slightly darkened. Wing. Length 2.0– 2.6 mm (♂, 2.0– 2.3 mm; ♀, 2.6 mm); 2.8–2.9 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 at halfway point of wing length, and at 2/3 point of cell dm length. Vein Cu extends to wing margin; apical section 1.3–1.6 X longer than crossvein dm-cu. Halter yellow.

Abdomen ( Figs 4 , 9 ). Tergites 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). Tergites silvery grey pruinose, except syntergite 1+2 mostly brown pruinose (silvery grey only laterally and along posterior margin), tergites 3–5 with pruinosity bronzy grey anterolaterally, tergite 3 with paired brown spots, and tergites 4 and 5 each with small median black (less pruinose) vitta extending posteriorly through 2/3 length. Sternites 3, 4 and 5 rounded trapezoidal, subequal, with slight emargination on posterior edge of sternite 5. Pregenital segments of male. Tergite and sternite 6 absent. Syntergosternite 7+8 saddle-shaped, less than half length of preceding tergite; sternite 7 small, lightly sclerotized, longer than wide, tapering posteriorly, bare.

Male genitalia ( Figs 5–8 ). Epandrium moderately convex posteriorly, with 6–9 setae along posterior part; smoothly tapering into distally pointed surstylar lobe; surstylus with sharpened edge, and distomedially with tiny setulae. Cercus small, with setulae at tip. Hypandrium in dorsal view subequal in length and width, widest in middle, with anterior half thicker than posterior half; in profile, slightly undulating, widest in middle and anteriorly, and abruptly narrower posteriorly. Pregonite articulating with widest point of hypandrium; parallel-sided, with blunt tip; dorsally setulose. Postgonite absent. Phallapodeme boomerang-shaped from lateral view, with the middle wide and tapering to each narrow tip; in ventral view club-shaped at posterior end. Phallus from ventral view widest anteriorly and tapering evenly with straight sides to tip, lateral part an even sclerotized strip with middle area membranous; length 2.5 X width at anterior end; at mid length each side with ventrolaterally directed extensions; thin and slightly undulating from lateral view.

Female terminalia ( Fig. 9 ). Tergite 6 about 3.3 X wider than long, length 0.7 X length of tergite 5; sternite 6 slightly enlarged, with width 0.5 X width of tergite 6, about 3 X wider than median length, and slightly wider than sternite 5, with long setulae along posterior edge, slightly emarginated on anterior and posterior edges; tergite 7 entirely membranous; sternite 7 small (half length and about 1/3 width of sternite 6), triangular, setulose on membrane posterior to sternite; tergite 8 subsquare, subequal in width to sternite 7, lightly sclerotized, with several long setulae along posterior margin; sternite 8 absent, entirely membranous, with corresponding setulose patch. Hypoproct tapering evenly to rounded tip. Epiproct subtriangular, with normal cercus bearing uniformly short setulae. Internally, spermathecae 2+2, round.

Immatures. Egg (from dissection of ♀) ( Fig. 10 ). Similar to typical leucopine eggs (e.g., Gaimari & Turner 1996), with the following particular characteristics: length 0.58–0.59 mm, width 0.22–0.23 mm; with series of 13–14 longitudinal ridges, rarely anastomosing except at posterior pole, and less so at anterior pole.

Type material. Holotype ♂ (point mounted, very good condition; Fig. 1A ), deposited in CSCA, with the following labels: “USA: Arizona; Apache Co., Apache Nat’l For., 0.5 km S mi. 249 on US Rte. 191, 8 km S. Alpine, along Coleman Crk.; 2500 m; 33°47’24”N 109°10’01”W, 30 JUN 1995, coll: S.D. Gaimari, ex: sweep Pinus ponderosa ” / “ HOLOTYPUS ♂ Chamaethrix necopina Gaimari ” (red label). Paratypes: USA. ARIZONA. Apache Co., Apache National Forest, nr. Alpine, 33°51’52”N 109°10’18”W, 2440 m, 28.vi.1995, coll: S.D. Gaimari, ex: sweep young Pinus ponderosa (1 ♀ (SDG dissection 1387), CSCA). NEW MEXICO. Lincoln Co., Lincoln National Forest, 2.4 km W Angus, Mills Canyon, along Rio Bonito, 33°27’05”N 105°41’46”W, 2130 m, 18–19.vi.1995, coll: S.D. Gaimari, ex: sweep colonies of Cinara ponderosae on Pinus ponderosa (1 ♂ (SDG dissection #1368), CSCA).

Distribution. Known from the southwestern United States (Arizona, New Mexico) in areas above 2100 m elevation. The species probably occurs in at least the intervening and surrounding areas at elevations and places characterized by stands of ponderosa pine.

Biology. All known specimens were swept from infestations of Cinara ponderosae (Williams) (Hemiptera: Aphididae ) in young stands of Pinus ponderosa (e.g., height less than 5 m throughout the large stand), but despite rearing>150 chamaemyiid larvae to adulthood from this host, none were this species. It remains a possibility that this species is a predator in that system, although species of non-aphid-feeding genera (e.g., Chamaemyia Meigen ) were also collected in the same sweep samples, presumably going to the aphids to feed on honey dew.

Remarks. At two different localities (one in New Mexico and one in Arizona), this species was collected together with Vitaleucopis nidolkah and the adelgid-feeding species Leucopis argenticollis Zetterstedt and Leucopis atrifacies Aldrich.

Figures

FIGURES 1–4. Chamaethrix necopina sp. nov., holotype ♂. Habitus, lateral view. 2. Head and thorax, dorsal view. 3. Head, dorsal oblique view. 4. Abdomen, dorsal view.

FIGURES 5–9. Chamaethrix necopina sp. nov. 5–8. Paratype ♂, genitalia. 5. Epandrial complex, lateral view. 6. Epandrial complex, posterior view. 7. Phallic complex, dorsal view. 8. Phallic complex, lateral view. 9. Paratype ♀, sternites 4–7, ventral view.Abbreviations: c = cercus, e = epandrium, h = hypandrium, pa = phallapodeme, ph = phallus, pr = pregonite, ss = surstylus, s6 = sternite 6, s7 = sternite 7. Scale bar = 0.1 mm.

FIGURES 10–11. Eggs from paratype ♀♀, dorsal view (posterior end left). 10. Chamaethrix necopina sp. nov. 11. Vitaleucopis nidolkah sp. nov. Note, the lighting difference between the two figures does not constitute morphological difference.