Nephus bisignatus (Boheman, 1850)

Pentinsaari, Mikko, Anderson, Robert, Borowiec, Lech, Bouchard, Patrice, Brunke, Adam, Douglas, Hume, Smith, Andrew B. T. & Hebert, Paul D. N., 2019, DNA barcodes reveal 63 overlooked species of Canadian beetles (Insecta, Coleoptera), ZooKeys 894, pp. 53-150 : 53

Nephus bisignatus (Boheman, 1850) Figure 34

Distribution

Previously known only from Europe, where the species is more common in the north and rather sporadic in the central and southern parts ( Fürsch 1965; Kovář 2007; Silfverberg 2010; Rassi et al. 2015). Probably Holarctic and previously overlooked in North America.

Canadian records.

Nunavut: Kugluktuk, 25-Jun-2010 (1 ex, CNC); Kugluktuk, 01-Jul-2010 (1 ex, CNC); Kugluktuk, 11-Jul-2010 (1 ex, CNC); Kugluktuk, 13-Jul-2010 (1 ex, CNC).

Diagnostic information

(based on Fürsch 1965, 1967, 1987). Body length 1.5-2.0 mm. Habitus elongate-oval ( Fig. 34A ). Black, with the anterior edge of the pronotum and often the apical edge of the elytra narrowly brown. Each elytron with a single small, obscurely delimited red-brown spot close to the apex, sometimes very faintly visible. Antennae with nine antennomeres. Pronotum very finely punctate, with strong, netlike microsculpture. Postcoxal lines on first abdominal ventrite briefly parallel to the hind margin of the ventrite at the middle, with the apices curved forward laterally. Male genitalia as in Fig. 34B, C .

Bionomic notes.

Nephus bisignatus prefers open, usually sandy habitats in Europe ( Koch 1989b). The Canadian specimens were collected in mesic tundra with yellow pan and pitfall traps.

Comments.

Nephus bisignatus belongs to subgenus Bipunctatus Fürsch, 1987, which is characterized by having only nine antennomeres ( Fürsch 1987). All the previously recorded Canadian species have either ten or eleven antennomeres ( Gordon 1976, 1985). The remote collecting localities in the arctic tundra indicate that this species is probably Holarctic and previously overlooked in North America rather than adventive from the Palaearctic region. Two subspecies are known from Europe ( Kovář 2007), but we refrain from assigning the Canadian specimens to any subspecies. Among the Nearctic fauna, N. bisignatus resembles N. georgei (Weise, 1929), but has a narrower body outline and usually smaller and less conspicuous elytral spots. Nephus georgei also has ten antennomeres instead of nine. Gordon (1976) notes that specimens of N. georgei from the northern parts of the Northwest Territories are smaller and narrower compared to specimens from southern Canada and northern United States, and that the pale color pattern of the elytra is reduced in the northern specimens. Based on these notes, the arctic specimens of N. georgei may actually represent N. bisignatus and need to be re-examined.

Figures

Figures 33, 34. 33 Chilocorus renipustulatus (Scriba) 33 A habitus, L. Borowiec 33 B median lobe (penis guide) and parameres, ventral view 33 C penis (sipho), tip in lateral view 34 Nephus bisignatus (Boheman) 34 A habitus, S. Karjalainen 34 B median lobe (penis guide) and parameres, lateral view 34 C penis (sipho), tip in lateral view. Scale bars: 1.0 mm (33 A), 0.5 mm (33 B; 34 A), 0.2 mm (33 C; 34 B), 0.1 mm (34 C).