Aleochara (Xenochara) castaneipennis Mannerheim

Klimaszewski, Jan, Webster, Reginald P. & Brunke, Adam, 2017, A new cryptic species of Aleochara Gravenhorst associated with Marmota monax (Linnaeus) burrows and caves in North America (Coleoptera: Staphylinidae: Aleocharinae), Insecta Mundi 2017 (600), pp. 1-11 : 5-6

Aleochara (Xenochara) castaneipennis Mannerheim

( Fig. 10 b, 11–19 )

Aleochara castaneipennis Mannerheim, 1843 . Klimaszewski 1984, Klimaszewski and Peck 1986 (misidentification of A. castaneimarmotae ), Lohse et al. 1990, Klimaszewski and Winchester 2002, Gouix and Klimaszewski 2007, Klimaszewski et al. 2005, Majka and Klimaszewski 2010, Majka et al. 2011, Klimaszewski et al. 2011.

Diagnosis. This species may be distinguished by the following combination of characters: body subparallel, length 2.8–6.5 mm; brown to dark brown, with tarsi and palps rusty-brown, elytra often paler than remainder of body ( Fig. 11 ); meshed microsculpture of forebody strong but broken or absent in many places ( Fig. 12 ); antennomers V–X strongly transverse ( Fig. 11 ). Male: tergite VIII truncate and slightly emarginate apically ( Fig. 15 ); sternite VIII strongly triangularly produced apically ( Fig. 16 ); median lobe of aedeagus with tubus evenly arcuate in lateral view ( Fig. 13 ), apex of tubus bent ventrad, subapical sclerites of internal sac with apex upturned but not hooked or sinuate ( Fig. 10 b); median lobe in dorsal view as illustrated ( Fig. 14 ). Female: tergite VIII truncate apically and shallowly emarginate medially ( Fig. 17 ); sternite VIII rounded apically with short apical pubescence ( Fig. 18 ); spermatheca L-shaped, capsule slightly elongate sac-shaped ( Fig. 19 ).

This species is often misidentified as the externally similar A. fumata , from which it differs by having slightly coarser pronotal punctation, interstices between punctures less glossy, body often larger and different genital features. It may also be confused with the western North American species A. quadrata Sharp , from which it can be distinguished by the distinctly paler disc of the pronotum compared to the head, evenly arcuate apical half of the tubus and subapical sclerite of the internal sac upturned at apex. For a comparison with its sibling species, A. castaneimarmotae , see above.

Distribution (verified localities). Origin: Nearctic. Canada: AB, BC, LB, NB, NF, NS, NT, ON, QC, YT. USA: AK, AZ, CO, WA, WY.

Based on a re-examination of the material originally examined by Klimaszewski (1984) and new material available to us, we state above only those records which can be confirmed here. Many of the state records south of the northeastern U.S. may refer to A. castaneimarmotae , but this needs to be confirmed. All specimens from Oregon and the available males from California listed by Klimaszewski (1984) refer to A. quadrata . All 134 specimens re-examined from Alaska (UAM), and identified by one of us (JK) as A. castaneipennis , are correctly identified.

Collection and habitat data. Habitat: coniferous, deciduous and mixedwood forest types, coastal limestone barrens. Adults often found in rotting mushrooms, carrion, forest leaf litter, moss, and human feces. In NB, this species was often abundant in decaying mushrooms but was seldom found in other microhabitats. Collecting period: IV–XI. Collecting method: sifting decaying mushrooms, forest litter, using unbaited and carrion-baited pitfall traps, flight intercept traps.

Figures

Figures 11–19. Aleochara castaneipennis Mannerheim. 11) Habitus in dorsal view. 12) Enlarged fragment of pronotum showing pubescence and microsculpture.13) Median lobe of aedeagus in lateral view.14) Median lobe of aedeagus in dorsal view. 15) Male tergite VIII.16) Male sternite VIII.17) Female tergite VIII.18) Female sternite VIII. 19) Spermatheca. Scale bar for habitus = 1 mm, remaining scale bars = 0.2 mm.