Dichelotarsus lapponicus (Gyllenhal, 1810)

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

Dichelotarsus lapponicus (Gyllenhal, 1810) Figure 27

Distribution.

Previously only recorded from the Palaearctic region. A northern species, found in Norway, Sweden, and Finland, and across the northern Palaearctic to the Russian Far East and Japan (Hokkaido) ( Kazantsev and Brancucci 2007; Silfverberg 2010; Rassi et al. 2015). Probably Holarctic and previously overlooked in North America.

Canadian records.

Yukon Territory: Ivvavik National Park, 17-Jun-2014 to 23-Jun-2014 (3 exx CBG); Ivvavik National Park, 23-Jun-2014 to 29-Jun-2014 (16 exx, CBG).

Diagnostic information

(based on Kazantsev 1998). Body length 7-10 mm. Habitus as in Fig. 27A . Dark brown to black, basal antennomeres, mandibles and usually clypeus (at least at the margins) yellow. Legs variably yellow, usually at least the profemora yellow. Third antennomere in males ca. 1.5 times as long as the second. Pronotum as wide as long or slightly wider than long, with sides concave before acute hind angles. All tarsal claws in both sexes with a broad, blunt basal tooth, no claws deeply cleft. Aedeagus as in Fig. 27B−D , with dorsal plate with apical notch.

Bionomic notes.

In Northern Finland, this species is found both above and below the treeline, usually in wetlands (MP, pers. obs.). The Canadian specimens were collected with a Malaise trap on tundra close to the Arctic treeline.

Comments.

The remote arctic collecting locality suggests that this species is more likely to be Holarctic than adventive from the Palaearctic region. The legs and basal antennomeres of the Canadian specimens are darker and the body length is slightly smaller compared to North European material we examined (including the DNA barcoded Finnish specimens with which the Canadian specimens share the BIN cluster). The male genitalia and shape of the pronotum show no differences between the European and Canadian specimens. Based on the identification keys, descriptions and figures by Fall (1927) and Fender (1961), D. lapponicus closely resembles D. piniphilus (Eschscholtz, 1830). The tarsal claw formula is the same and the shape of the pronotum is very similar in both species. The dorsal plate of the aedeagus has an apical notch in D. lapponicus (as in Fig. 27B ), whereas in D. piniphilus it is apically truncate or subtruncate. The clypeus of D. lapponicus is usually yellow at least at the margins. The yellow color is more extensive in males in the material we have seen, and only faint red-brown spots are visible on the clypeus of some female specimens. The clypeus is black in D. piniphilus . Pelletier and Hébert (2014) state that D. lapponicus resembles D. perplexus (W.J. Brown, 1940), which is known from across boreal and arctic Canada, but D. perplexus is smaller (body length 5.0-6.5 mm) and has a different tarsal claw formula.

Figures

Figures 27, 28. 27 Dichelotarsus lapponicus (Gyllenhal) 27 A habitus 27 B aedeagus, ventral view (everted endophallus removed) 27 C aedeagus, lateral view (everted endophallus removed) 27 D endophallus, lateral view 28 Malthodes pumilus (Brebisson), habitus, L. Borowiec. Scale bars: 2.0 mm (27 A), 0.5 mm (27 B-D), 0.3 mm (28).