Acrotona manitobensis Klimaszewski and Godin, 2018

Klimaszewski, Jan, Godin, Benoit, Davies, Anthony, Bourdon, Caroline & Horwood, Denise, 2018, Forty new records of aleocharine beetles, and two new species in the genera Acrotona Thomson and Atheta Thomson, for the province of Manitoba, Canada (Coleoptera: Staphylinidae: Aleocharinae), Insecta Mundi 2018 (641), pp. 1-33 : 10

Acrotona manitobensis Klimaszewski and Godin , new species

Fig. 1–8

Holotype. Canada: Manitoba, Max Lake , 2016-IX-10, 49.0714°N, 100.1384°W, 686 m, mushrooms, sifting, coll. B. Godin & D. Horwood ( CNC) 1 male.

Paratype. Canada: Manitoba, Katherine Lake, 2016-IX-14, 50.6603°N, 99.8947°W, 652 m, litter, sifting, coll. B. Godin & D. Horwood ( LFC) 1 female.

Etymology. Named after the Canadian province of Manitoba, where the type specimens were found.

Description. Body narrow and subparallel ( Fig. 1 ), moderately convex; length 2.8-2.9 mm, width at middle of pronotum 0.9 mm, width at base of elytra 0.6 mm; colour dark brown with elytra and apical segments of abdomen slightly paler rufobrunneous, appendages brunneotestaceous; punctation on forebody fine, moderately dense and slightly asperate, particularly on pronotum ( Fig. 1 ); head distinctly narrower than pronotum, ratio of maximum width of head to maximum width of pronotum 0.7; antennomeres VII–X subquadrate; pronotum broad and shield-shaped, sides evenly arcuate, maximum width of pronotum greater than width of elytra at base, ratio of maximum width to length 1.4; elytra at suture shorter than pronotum; abdomen slightly tapering posteriorly. Male. Tergite VIII moderately transverse, apical margin arcuate ( Fig. 4 ); sternite VIII elongate, broadly parabolically rounded from base to apex, base slightly sinuate ( Fig. 5 ); tubus of median lobe of aedeagus in lateral view short, with ventral margin curved obliquely ventrad in basal half and almost straight in apical half, with apex narrow and rounded, internal sac with narrow, sclerotized, curved subapical structure ( Fig. 2 ); in dorsal view median lobe with tubus narrow, subparallel, broadly rounded apically, bulbus very wide, subovoid, internal sac with two narrow arcuate structures ( Fig. 3 ). Female. Tergite VIII similar to that of male ( Fig. 6 ); sternite VIII elongate, apex rounded, base evenly arcuate ( Fig. 7 ); spermatheca with capsule kidney-shaped, stem narrow, with single broad coil posteriorly ( Fig. 8 ).

Distribution. Known only from the type locality in Manitoba.

Collection and habitat data. Captured in September by sifting organic litter in deciduous forest and mushrooms.

Comments. This species differs from all other Nearctic Acrotona species known to us in combination of the following characters: broad and shield-shaped pronotum that is wider than base of elytra, elytra at suture shorter than pronotum, unique shape of median lobe of aedeagus with large bulbus and two elongate narrow structures of internal sac ( Fig. 2, 3 ), distinct shape of tergite and sternite VIII of male and female ( Fig. 4–7 ), and the distinct shape of spermatheca ( Fig. 8 ).

Figures

Figures 1–8. Acrotona manitobensis Klimaszewski and Godin, sp. nov., habitus and male structures of holotype. 1) Habitus in dorsal view. 2) Median lobe of aedeagus in lateral view. 3) Median lobe of aedeagus in dorsal view. 4) Male tergite VIII. 5) Male sternite VIII. 6) Female tergite VIII. 7) Female sternite VIII. 8) Spermatheca. Scale bar for habitus = 1 mm, remaining scale bars = 0.2 mm.