Revision of Quedius sensu stricto (Coleoptera: Staphylinidae) Author Hansen, Aslak Kappel Natural History Museum of Denmark, Zoological Museum, Universitetsparken 15, 2100 Copenhagen, Denmark; e-mails: akhansen @ snm. ku. dk; asolodovnikov @ snm. ku. dk & Natural History Museum Aarhus, Wilhelm Meyers Allé 10, 8000 Aarhus, Denmark & Department of Bioscience, University of Aarhus, Ny Munkegade 116, 8000 Aarhus, Denmark Author Brunke, Adam Agriculture and Agri-Food Canada, 960 Carling Avenue, Ottawa, Ontario, K Author Simonsen, Thomas Natural History Museum Aarhus, Wilhelm Meyers Allé 10, 8000 Aarhus, Denmark Author Solodovnikov, Alexey Natural History Museum of Denmark, Zoological Museum, Universitetsparken 15, 2100 Copenhagen, Denmark; e-mails: akhansen @ snm. ku. dk; asolodovnikov @ snm. ku. dk & Zoological Institute, Russian Academy of Science, Universitetskaja nab. text Acta Entomologica Musei Nationalis Pragae 2022 Acta. Ent. Mus. Natl. Pragae 2022-11-26 62 1 225 299 http://dx.doi.org/10.37520/aemnp.2022.017 journal article 217329 10.37520/aemnp.2022.017 795cf556-a4a9-477b-b55d-cb80ed8a0f2d 1804-6487 7399702 28D55112-98B1-49A5-B382-58B1B068570B Quedius strenuus Casey, 1915 ( Figs 1 , 4 , 9F , 14F , 22 ) Quedius strenuus Casey, 1915: 401 [ Type locality: Texas ] References. Sආൾඍൺඇൺ (1971a): 132 ( lectotype designation, characters and distribution); (1981): 638, (1990): 98 (distribution). Type material examined. Lൾർඍඈඍඒඉൾ: ♀ , designated by Sආൾඍൺඇൺ (1971a) ( USNM ) [not examined], labelled: “Tex / Casey bequest 1925/ Type USNM 48279 / strenuus Csy ”. Additional material examined. USA : Kൺඇඌൺඌ: Lawrence, below bridge, Kansas River,[38.96, -95.26],under chunk of mud flat, 16.X.1936 , leg. M. W. Sanderson (1 CNC ). Tൾඑൺඌ: Braunfels, [29.69, -98.11], 13.VI.1927 , leg. Darlington (1 MCZ ); Del Rio, [29.36, -100.9], 8.VII.1938 , leg. R. L. Sailer (3 CNC ); Kerrville, [30.02, -99.13], 11.IV.1998 , leg. Chamberlain (3 TAMU ); Uvalde County, [29.30, -99.70], 26.V.1938 , leg. J. H. Robinson (1 CNC ). Redescription. Measurements JJ (n = 3): HW = 1.60– 1.82 (1.73); HL = 1.33–1.51 (1.44); HL/HW 0.80–0.85 (0.83); PW = 2.20–2.47 (2.37); PL = 2.02–2.22 (2.14); PL/PW 0.89–0.92 (0.90); EW = 2.33–2.60 (2.50); EL = 2.00–2.24 (2.16); EL/EW 0.85–0.88 (0.86); EL/PL 0.99–1.03 (1.01); PW/HW 1.63–1.67 (1.65); forebody length 5.36–5.96 (5.73). ♀♀ (n = 2): HW = 1.69–1.76 (1.72); HL = 1.44–1.47 (1.46); HL/HW 0.82–0.87 (0.85); PW = 2.33–2.44 (2.39); PL = 2.07–2.09 (2.08); PL/PW 0.85–0.89 (0.87); EW = 2.62–2.64 (2.63); EL = 2.18–2.29 (2.23); EL/EW 0.83–0.87 (0.85); EL/PL 1.05–1.10 (1.07); PW/HW 1.59–1.69 (1.64); forebody length 5.71–5.82 (5.77). Medium sized, robust species; body black (Fig, 9F). Head black, distinctly transverse, with eyes medium sized (EyL/TL = 1.76–2.00 (1.88)); microsculpture of transverse waves; no additional punctures between anterior frontal punctures ( Fig. 6F ); all antennomeres elongate, antennae and palpi reddish. Thorax: pronotum black, slightly wider than long, wider than head, with microsculpture of transverse waves; three punctures in dorsal row and one to two in sublateral row with its posteriormost puncture reaching just beyond first puncture of dorsal row; scutellum punctured and pubescent; elytra black, uniformly pubescent, slightly wider than long, roughly as long as pronotum; legs reddish brown with inner face of tibia and femur darkened. Abdomen black, tergites uniformly punctured, with slight iridescence. Male. Aedeagus ( Fig. 14F ): paramere rather broad lanceolate, slightly protruding beyond apex of median lobe, with sensory peg setae forming two distinct short and wide rows of multiple punctures; median lobe broad with gentle constriction towards pointed apex, on parameral side with two small hooked teeth protruding slightly basad, positioned at level near lower level of peg setae patch of the paramere. Differential diagnosis. Quedius strenuus is similar to Q. laticollis from which it normally differs by the completely dark body with pale appendages. For confident delimitation of both species from each other the position of the peg setae of the paramere can be used, which form two distinct rows in Q. strenuus and a triangular patch in Q. laticollis . Co-occurrence of the two species is unlikely since Q. strenuus replaces Q. laticollis to the west, in the forested areas of Great Plains of central-eastern and lowland areas of the southwestern United States . Quedius strenuus is also very similar to the introduced species Q. molochinus , which has not yet been found within the distribution range of Q. strenuus . Other differences include that, in Q. molochinus , the antennae are slightly stouter, less elongate, with darker middle antennomeres; as well as elytra are finer and more densely punctate, and either brick red or dark red (always dark in Q. strenuus ). Quedius strenuus cannot be confused with other North American Quedius as they either have interocular punctures on frons or (those from other subgenera) have clear medial incision of labrum and abdomen notably tapering apicad. Bionomics. Little is known about the bionomics of Q. strenuus . Based on current records, Q. strenuus is most likely restricted to lowland sites. As the region covered by its distribution is rather arid and most specimens were found near creeks, rivers, and lakes, it is likely to be strictly confined to moist microhabitats like wet flood or water-edge debris. Distribution. Quedius strenuus is found across the Great Plains (ecoregion 9.4) and potentially a large part of lowland southwest United States (parts of ecoregion 10, Fig. 22 ). Only a few specimens, which we were not able to examine, were imprecisely recorded from lowland Southwest United State, from Arizona and Southern California . Of these, only a record from Lyman Lake in Apache County, Arizona (Sආൾඍൺඇൺ 1981) is exact and fully reliable. Earlier Sආൾඍൺඇൺ (1971a) mentioned subtle differences between these lowland specimens and ones from the Great Plains, but not clear enough to describe an additional species. The known range of Q. strenuus extends southwards almost to the border between USA and Mexico , northwards to Lawrence in Kansas. To the east Q. strenuus is replaced by Q. laticollis .