Trichiusa robustula Casey, 1893

Brunke, Adam J., Pentinsaari, Mikko & Klimaszewski, Jan, 2021, Integrative taxonomy of Nearctic and Palaearctic Aleocharinae: new species, synonymies, and records (Coleoptera, Staphylinidae), ZooKeys 1041, pp. 27-99: 27

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Trichiusa robustula Casey, 1893


Trichiusa robustula Casey, 1893   Fig. 36A-I View Figure 36

Trichiusa robustula   Casey, 1893

Trichiusa immigrata   Lohse, 1984, syn. nov.


(DNA-barcoded specimens). Austria: Innervillgraten, Arntal, 46.8362, 12.3348, mountain forest and alpine pastures, car net, 25.VIII.2013, GBOL-Team ZFMK (1, ZFMK) GoogleMaps   . Germany: Nuernberg, N Flughafen, 49.5006, 11.0789, sifting compost, date not provided, GBOL-Team ZFMK (1, ZFMK); Schoenau / Hoersel, W, Gewerbegebiet, 50.947, 10.4214, sifting compost, 25.VIII.2012, GBOL-Team ZFMK (2, ZFMK); Kahlenberg / Eisenach, Pferdekoppel, 50.9469, 10.4287, in horse dung, 16.IX.2013, GBOL-Team ZFMK (1, ZFMK) GoogleMaps   . Finland: Ka: Hamina, Meltti, 60.5798, 27.2016, 12.X.2011, M. Pentinsaari (1, ZMUO); Al: Mariehamn, Dalen, 60.0703, 19.9595, 9.X.2011, M. Pentinsaari (2, ZMUO) GoogleMaps   . Canada: Ontario: Guelph, Division Street, 43.5544, -80.2644, malaise trap, 14.VII.2010, A. Smith (1, CBG); Chelsey , Chelsey District Community School , EQP-CLL-581, 44.3028, -81.0967, 281 m, malaise trap, 22.IX-3.X.2014, A. Grieve (1, CBG); Guelph, Arboretum, Urban Organic Farm, 43.5381, -80.222, compost heaps/mouldy hay pile, 17.IX.2017, M. Pentinsaari (6, CBG) GoogleMaps   .

Additional material

(non-barcoded). Numerous dissected specimens from Denmark were examined in the collection of NHMD.


Origin. Nearctic (adventive in Europe). Canada: ON, NB. United States: IA.


In its native range, this species has been collected in a variety of decaying plant matter, especially near water. This species was also common in compost in NB. In Europe, this species has been collected from similar microhabitats including grass clippings and compost ( Denton 1998; Anderson and Bryan 2012).


Trichiusa robustula   is a Nearctic species that is broadly distributed in eastern North America but not well collected. It was previously recognized under the synonym T. immigrata   Lohse in the West Palaearctic (Europe, Canary Islands, Madeira; Newton 2019), where it is adventive.

When describing his new species, Lohse (1984) noted that it must have originated from North America, since Trichiusa   is otherwise endemic to that region. Lohse (1984) stated that T. immigrata   was compared with types of North American species described by Casey (1893), but this taxon is a morphological and molecular match to T. robustula   . Although most of the specimens collected in North America are bicolored (reddish/dark), study of extensive material from Denmark (NMHD) revealed a grade between fully dark brown to reddish/dark bicolored. Trichiusa robustula   is distinctive for the shape of its spermatheca, which bears a rectangular capsule, and stem that has a single 180-degree bend followed by a twisted apical portion (Fig. 36C View Figure 36 ). The figure of the spermatheca in Klimaszewski et al. (2018) is atypical (Fig. 36C View Figure 36 ) and the original illustrations in Brunke et al. (2012), reproduced here (Fig. 36D, E View Figure 36 ), better show these features.














Trichiusa robustula Casey, 1893

Brunke, Adam J., Pentinsaari, Mikko & Klimaszewski, Jan 2021

Trichiusa immigrata

Lohse 1984

Trichiusa robustula

Casey 1893