Nephrocerus acanthostylus, Skevington, Jeffrey H., 2005

Skevington, Jeffrey H., 2005, Revision of Nearctic Nephrocerus Zetterstedt (Diptera: Pipunculidae), Zootaxa 977, pp. 1-36 : 8-12

Nephrocerus acanthostylus sp. nov. ( Figs 1 A, C, 2A, 3A–D, 4A, 5)

Type Material Examined: Holotype ♂: Canada, Quebec, [Vaudreuil Co., Summit of] Mount Rigaud, 45°27'59" N, 74°19'35" W, 19.v.2004, JSS#15348, J. Skevington, L. Bartels, E. St. Louis, J. King ( CNC). Allotype Ψ: United States, Minnesota, Becker Co., 6 mi [les] SW Detroit Lakes, [46°49' N, 95°51' W], Malaise trap, in hardwood forest, 6– 8.vi.1981, JSS#13491, Mike Moher ( CAS). Paratypes: Canada: New Brunswick: Kouchibouguac N[ational] P[ark], [46°52' N, 64°58' W], 27. vi.1977, 1 ♂, JSS#11449 [head and dissected genitalia in glycerin, all very faintly pigmented, apparently due to long time in KOH; all legs removed for DNA extraction], S.J. Miller, 5437C ( CNC); Ontario: Hilton Beach, [46°15' N, 83°53' W], Malaise trap, at edge of h[ar]dw[oo]d for[est] and field, 31. v.1990, 1 ♂, JSS#11411 [3 legs removed for DNA extraction], 1Ψ, JSS#11414 [3 legs removed for DNA extraction], 6. vi.1989, 2 ΨΨ, JSS#11417­8, 9. vi.1989, 1 Ψ, JSS#11419, 9. vi.1990, 1 Ψ, JSS#15952, 13. vi.1990, 2 ΨΨ, JSS#11421­2, 19. vi.1989, 1 Ψ, JSS#11420, J.E. Swann ( DEBU); [Carleton Co.], Stittsville, [45°15' N, 75°55' W], 24. vi.1963, 1 Ψ, JSS#11473, W.R.M. Mason ( CNC); United States: Michigan: Emmet Co., [45°32' N, 84°55' W], 27. v.1960, 1 Ψ, JSS#11512, R.&K. Dreisbach ( USNM); Barry Co., T3N R10W, Sec. 26, [42°36' N, 85°19' W], 29. v.1968, 1 Ψ, JSS#11511, J.P. Donahue ( USNM); Minnesota: Becker Co., 6 mi [les] SW Detroit Lakes, [46°49' N, 95°51' W], Malaise trap, in hardwood forest, 29. v.1981, 1 ♂, JSS#13490, 2ΨΨ, JSS#13492­3, 3. vi.1981, 4 ΨΨ, JSS#13475­ 8, 4. vi.1981, 2 ΨΨ, JSS#13481, 13487, 5. vi.1981, 1 ♂, JSS#13485 [3 legs and tergites 2 and 3 removed for DNA extraction], 6. vi.1981, 1 Ψ, JSS#13482, Mike Moher ( CAS); New Hampshire: Carr[oll] Co., The Bowl, 2.5 mi[les] NW Wonalancet, [43°56' N, 71°24' W], Malaise trap, 5–8. vi.1984, 1 Ψ, JSS#11825 [3 legs removed for DNA extraction], 21– 27. vi.1984, 2 ΨΨ, JSS#11829­30, 5–14. vi.1985, 1 Ψ, JSS#11845, D.S. Chandler ( DENH); Virginia: Shenandoah N[ational] P[ark], Big Meadow, [38°30' N, 78°27' W], 1300 m, Malaise trap, natural meadow, 8–20. v.1987, 1 ♂, JSS#11472, BRC Hym. Team ( CNC).

Other Material Examined: Allotype Nephrocerus slossonae Ψ: [ United States], N[ew] H[ampshire], Bretton Woods, 25.vi.1913, JSS#13450, C.W. Johnson, [13093] ( MCZ).

Etymology: An adjective, from the Greek akantha for ‘thorn’; in reference to the thorn­like projection off the left surstylus.

Description: Male: Body length 7.0–8.2 mm. Head: Holoptic, eyes joined for length of ocellar triangle or slightly longer, H:O 0.88–1.62:1. Arista black with yellow base. 1st flagellomere yellow. Pedicel yellow with 19–23 bristles along distal margin. Scape yellow with 3–8 dorsal bristles. Labellum and palps yellow. Occiput silver­pubescent with multiple rows of white hairs. Thorax: Proepisternum with a fan of 8–13 bristles. Postpronotal lobe yellow with 6–7 yellow hairs on posterior edge. Scutum black dorsally, yellow laterally, with sharply defined boundaries between the colours ( Fig. 1 A); with dorsocentral and intra­alar rows of short hairs, dorsocentrals increasing in size posteriorly and terminating in 1–2 strong setae. Notopleuron with 1–2 setae and numerous smaller hairs. 1–2 posterior supra­alar setae. Postalar callus with 1–3 setae and 6–7 other moderately strong bristles. Scutellum black with yellow around edges ( Fig. 1 A); with 2 pairs of strong posterior setae and numerous small black bristles over entire surface. Pleuron mostly yellow, black on basal four fifths of katepisternum and meron, on small sclerite below wing base, subscutellum, and in a thin band posterior to posterior spiracle; slightly darkened on anterior anepisternum and anepimeron, rarely on proepisternum. Halter yellow. Legs: entirely yellow, long and slender; hairs and sockets on coxae, trochanters and femora all yellow; tibiae and tarsi with yellow hairs but with black sockets. Fore and mid­tibiae slender and slightly arched dorsoventrally; hind tibia narrow on basal third, broader towards tip, laterally arched in apical half (in dorsal view); apex with circlet of stiff yellow bristles and a ventral patch of black specialized bristles ( Fig. 2 A). Trochanters with 1–3 dorsomedial bristles and a loosely arranged double row of shorter ventral bristles. Wings: Length: 5.6–7.4 mm; fourth costal section about 3 times as long as third, C4:C3 3.1–3.2:1; R­M position variable, situated between basal one­fourth to nearly middle of discal medial cell (dm), S3:S2 2.4–4.0:1. Cell r1 and Sc completely microtrichose , cell bm microtrichose on distal half (the only exception is in JSS#13490, which has the proximal corner of r1 bare). Tegula with 9–25 predominantly black bristles, including 2–4 much longer, yellow bristles along posterolateral margin. Abdomen: Tergite 1 black dorsally, entirely yellow laterally. Tergites 2–6 black dorsally, yellow posterolaterally to laterally. Sternites 1–5 yellow to brown. Tergite 1 with 6–8 large yellowish bristles. Tergite 7 yellow. Syntergosternite 8 mostly black , yellow near junction with epandrium. All hairs yellow. Genitalia: Epandrium and terminalia mostly yellow, only phallus black . Epandrium nearly as long as wide, WE:LE 1.1–1.3:1. Surstyli asymmetrical; lower lobe of left surstylus with distinctive hook; right surstylus with upper lobe short, acute, with cluster of long bristles on dorsomedial surface ( Fig. 3 A, C, D). Distiphallus with a few weak spines clustered on first loop ( Fig. 3 A–C). Female: As male except: Apex of hind tibia with no specialized bristle patch. Ovipositor short, upcurved, 0.91–1.06 mm ( Fig. 4 A). OL:PL 1.20–1.54:1; BL:OL 6.48–7.42:1; B:PL 0.27–0.46:1.

Distribution: Known from 31 specimens from NE North America, from Ontario to New Brunswick south as far as Virginia ( Fig. 5 ).

Comments: This species has been recorded from hardwood forests and a meadow. The holotype was collected on a hilltop as it hovered and flew over a serviceberry shrub [ Amelanchier sp.]. This behaviour was common to many other male flies present at the time, including other pipunculids and suggests that this species is a hilltopper. Four species of Nephrocerus have been collected hilltopping: N. acanthostylus , N. atrapilus , N. slossonae and N. woodi . This is a common mating strategy in Pipunculidae but has not been documented for Nephrocerus (Skevington 2001, 2002, 2003). I suspect that with additional observations, all six species of Nephrocerus will be discovered using this mating strategy. Parasitoid flies, particularly rare species, often employ this method of mate location ( Scott 1968; Shields 1967; Thornhill & Alcock 1983).

The flight period for this species is from May 14th to June 27th with most records focused around the first week of June.

Figures

FIGURE 1. Photographs of Nephrocerus species. Abbreviation: prepst = proepisternum. Scale bars = 1.0 mm. A. Nephrocerus acanthostylus, holotype, JSS # 15348, ♂, dorsal of head, thorax and base of abdomen. B. Nephrocerus slossonae, JSS # 11834, ♂, dorsal of head, thorax and base of abdomen. C. Nephrocerus acanthostylus, JSS # 13450, Ψ, left lateral. D. Nephrocerus slossonae, JSS # 11836, ♂, left lateral of head and thorax. E. ♂, Nephrocerus slossonae, JSS # 11490, left lateral of head and thorax.

FIGURE 2. Posterior view of distal region of right hind tibia, Nephrocerus species. Scale bars = 0.1 mm. A. Nephrocerus acanthostylus JSS # 13490. B. Nephrocerus corpulentus JSS # 11470. C. Nephrocerus slossonae JSS # 11827.

FIGURE 3. Male Nephrocerus acanthostylus terminalia, ejaculatory apodeme and sperm pump removed; all of JSS # 11411. Abbreviations: cerc = cerci; epand = epandrium; gpd = gonopod; hypd = hypandrium; llsur = lower lobe of surstylus; phapod = phallapodeme; ph = phallus; pgt = postgonite; ulsur = upper lobe of surstylus. Arrows indicate key features. Scale bars = 0.1 mm. A. left lateral. B. right lateral. C. dorsal. D. ventral, phallus removed.

FIGURE 4. Left lateral of ovipositors of female Nephrocerus species. Abbreviations: B = length of ovipositor base; cerc = cercus; OL = ovipositor length; PL = piercer length; spt = spermatheca, S = sternite; T = tergite. Scale bars = 0.1 mm. A. Nephrocerus acanthostylus, JSS # 13477. B. Nephrocerus atrapilus, JSS # 13397. C. Nephrocerus corpulentus, JSS # 13365. D. Nephrocerus daeckei, JSS # 11407. E. Nephrocerus slossonae, JSS # 11795.

FIGURE 5. Distributions of Nephrocerus acanthostylus and Nephrocerus atrapilus.