Quediellus humilis Casey, 1915

Brunke, Adam J., 2022, A world generic revision of Quediini (Coleoptera, Staphylinidae, Staphylininae), part 1. Early diverging Nearctic lineages, ZooKeys 1134, pp. 129-170 : 129

Quediellus humilis Casey

Type material.

Holotype (male, United States National Museum of Natural History, not examined): “Cal”. / Casey bequest 1925 / Type USNM 48306 / Quediellus humilis Csy. Smetana (1971) mentioned that this specimen was a small male of Q. nanulus . While it was not studied, several small non-type males were examined from northern California that perfectly fit the ‘nanulus’ morphotype, including some examined by Smetana (1971) himself and identified as Q. nanulus .

Non-type material.

Canada: Alberta: Marmot Creek, 10 mi SW Kananaskis F.E.S., 15.VIII.1971, 5000', sifting deciduous litter along large stream, J.M. Campbell (1 male, 1 female, CNC); Waterton Lakes N.P., mi 2 of Red Rock Canyon Road, 16.VI.1980, 4400', J.M. Campbell (1 male, 1 female CNC); Waterton Lakes N.P., 1 mi N Pass Creek Bridge, 4500', sifting Populus litter in moist deciduous forest, 5.VIII.1976, J.M. Campbell (1 male, 1 female, CNC). British Columbia: Greater Vancouver: Stanley Park, 20.V.1989, A. Smetana (2, CNC); same except 28.V.1968, Campbell and Smetana (1, CNC); same except 21.V.1968, Campbell and Smetana (1, CNC); Brunswick, 20.V.1968, Campbell and Smetana (1, CNC); Langley, open oak forest, 10.XII.1979, S. Rahe (2, CNC); Fraser Valley: Mission, berlese sample, 25.VII.1953, W.R.M. Mason (2, CNC); Vancouver Island: Chemainus Lake, mushrooms and rotten fir wood, edge of path, 25.IX.2020, A. Davies (1, CNC); Mesachie Lake, Forest Experiment Station, 1950 m, woody debris from log, 23.VII.1979, I. Smith (2, CNC); Salt Spring Island, Fulford Harbour, Petroglyph, 25.IX.1974, BD Ainscough (2, CNC); Gabriola Island, Gabriola, marsh with sedges, pitfall traps, 30.IX.1994, BF & JL Carr (1, CNC); same except sifting maple litter beside firewood and compost bin, 30.IV.1993 (3, CNC); same except sifting moss in forest near Hoggan Lake, 14.VI.1989 (1, CNC); Englishman River Provincial Park, cedar litter, 10.III.1997, B.D. Ainscough (1, CNC); Yellow Point, Cedar, under rotten log, 18.V.1978, B.D. Ainscough (1, CNC); Lake Cowichan, spring run beside North Shore Road, 1.7 km N town, moss and litter, 7.VI.1979, I. Smith (1, CNC); Stamp Falls [Stamp River] Provincial Park, 8 mi NW Alberni, 26.V.1968, Campbell and Smetana (2, CNC); Victoria, sifting litter and grass, 28.X.1985, BF & JL Carr (1, CNC).

United States: California: Alpine Co.: 22 mi NE Strawberry, Clark Fork River near Cottonwood Creek, 1767 m, 14.VII.1976, L. & N. Herman (1, CNC); Amador Co.: 4 mi S Jackson, sift oak, maple and alder litter, 3.II.1979, D.S. Chandler (1, FMNH); 1 mi W Pine Grove, 24.VI.1975, A. Newton and M. Thayer (1, CNC); 'Mokel Hill’ [= Mokelumne Hill], VII.1925, VanDyke (4, CNC); Alameda Co.: Berkeley, under Umbellifera duff, 23.II.1962, J.F. Lawrence (1, CNC); El Dorado Co.: Lake Tahoe, Taylor Creek at Camp Richardson, 1900 m, 9.VII.1986, A. Smetana (2, CNC); Humboldt Co.: 5 mi N Trinidad, Patricks Point State Park, hemlock/pine/alder litter, 14.VIII.1966, J+S Cornell (1, FMNH); Eureka, VI.1902, H.S. Barber (2, CNC); Marin Co.: Lagunitas Creek, near Tocaloma, 18.III.1983, A. Smetana (5, CNC); Monterey Co.: Jamesburg, Ian Moore (1, CNC); Placer Co.: Meeks Bay, West Lake Blvd, 1917 m, ex. riparian litter, 15.XI.2008, A. Brunke (1, DEBU); Lake Tahoe, Tahoe City, 1950 m, 7.VII.1986, A. Smetana (2, CNC); Tahoe Pines, 3.V.1968, Campbell and Smetana (1, CNC); Tahoe Pines, 1889 m, 10.VIII.1969, A. Smetana (2, CNC); San Diego Co.: San Diego, F.E. Blaisdell (1, CNC); Sonoma Co.: Annadel State Park, Hunter Spring nr. Canyon Trail, 220 m, 26.IV.-17.V.2007, P. Kerr and S. Blank (1, UTCI); Sobre Vista, 24.IV.1910, Van Dyke (1, CNC); Trinity Co.: Upper Canyon Creek Lake, 17mi N Junction City, 1737 m, 12.VII.1979, JM & BA Campbell (6, CNC); Upper Canyon Creek Meadows, 16mi N Junction City, 1463 m, 13-19.VII.1979 (1, CNC); Nevada: Douglas Co.: Zephyr Cove, 1900 m, 9.VII.1986, A. Smetana (3, CNC); Oregon: Columbia Co.: Oak Island, Sauvies Lake, Columbia River, 5mi N 2mi E Burlington, 30 m, Oregon oak and snowberry duff, 7.X.1972, E.M. Benedict (2, CNC); Curry Co.: 4mi S Pistol River, on US 101 (Mark 342), 60 m, Sitka spruce duff and soil, 12.II.1972, E.M. Benedict (1, CNC); Douglas Co.: 1mi S & 2mi W Ash, 152 m, deciduous Myrtle litter and duff, 11.XII.1971, E.M. Benedict (1, CNC); ~4.5mi E Wells Creek, Ranger Station, Umpqua River, 91 m, oak duff and soil, 11.XII.1971, E.M. Benedict (1, CNC); Klamath Co.: Mares Egg Springs, 1280 m, 20.VII.1979, JM Campbell & J Schuh (4, CNC); same except 25.VI.1974, A. & D. Smetana (1, CNC); 7 mile Creek, west of Forth Klamath, 20.VII.1979, JM Campbell & J Schuh (1, CNC); Lane Co.: Coast Guard Road, Approximately 1mi N Florence, 152 m, moss festoons, 6.V.1972, E.M. Benedict (2, CNC); Lincoln Co.: Eakman [= Ekman] Lake, 5mi E Waldport, 0 m, beach grass, 5.V.1973, E.M. Benedict (2, CNC); Tillamook Co.: Rest area, Wilson River Highway, 0.5mi S & 1mi W Lee’s Camp, western red cedar and red alder, 4.XI.1972, E.M. Benedict (2, CNC); Washington Co.: 0.25mi E Sherwood Highway & US-99W, 60 m, rotten hay, barley and dung, 1.I.1972, E.M. Benedict (2, CNC); Washington: Jefferson Co.: Olympic National Park, Hoh Ranger Station, 182 m, 13.V.1968, Campbell and Smetana (1, CNC); same except 19.VIII.1979, JM & BA Campbell (4, CNC); San Juan: San Juan Islands, Jones Island, 2.V.1988, J. Bergdahl (2, CNC); San Juan Islands, Matia Island, 28.VIII.1988, J. Bergdahl (2, CNC); San Juan Islands, Flattop Island, 22.I.1988, J. Bergdahl (1, CNC); San Juan Islands, Stewart Island, 18.X.1987, J. Bergdahl (1, CNC); same except 6.VIII.1988 (1, CNC); Sucia Island, 28.VIII.1988, J. Bergdahl (4, CNC); same except 30.VIII.1988; San Juan Islands, Jones Island, 2.V.1988, J. Bergdahl (3, CNC); San Juan Islands, Clark Island, 27.VIII.1988, J. Bergdahl (1, CNC); Skagit Co.: San Juan Islands, Fidalgo Island, 5.IV.1986, J. Bergdahl (4, CNC); Snohomish Co.: Chase Lake, 15.VIII.1961, W. Suter (2, CNC); Siskiyou Co.: VII, C.V. Riley (2, CNC); Whatcom Co.: Deming, S end Sumas Mt., Reardon property, ANMT site 1275, 95 m, berl., leaf & log litter incl. under Phlebia polypores on log, 2nd growth Pseudotsuga - Thuja - Alnus - Acer macrophyllum & circinatum, 13.XI.2014, A. Newton & M. Thayer (1, FMNH).

Diagnosis.

As in generic diagnosis.

Redescription.

Measurements ♂ (n = 10 (5 macropterous; 5 brachypterous)): HW/HL 1.07-1.17; PW/PL 1.02-1.19; EW/EL 1.08-1.29; ESut/PL 0.54-0.79; PW/HW 1.14-1.27; forebody length 2.3-3.1 mm.

Measurements ♀ (n = 10 (5 macropterous; 5 brachypterous)): HW/HL 1.10-1.15; PW/PL 1.04-1.14; EW/EL 1.15-1.36; ESut/PL 0.56-0.82; PW/HW 1.14-1.30; forebody length 2.5-3.2 mm.

Head dark brown, darker than pronotum, which is paler, entirely brown to pale reddish with yellow borders; elytra brownish, often with epipleural area, and lateral and apicolateral parts of disc paler, frequently contrasting yellow; abdomen dark brown, tergites at most narrowly paler at apex; antennae brown, with antennomeres 1-3 paler, yellow-brown or at least bases paler; legs pale, yellow to yellowish brown, tibiae dark brown; palpi yellowish brown to dark brown (Fig. 12 ).

Head slightly transverse, eyes large, moderately convex and protruding from lateral outline, temples small, about 1/4 to 1/3 of eye length (Fig. 5C ); disc of head with sparse microsculpture of transverse waves, spaces between lines greater than width of lines; antennomeres of varying shape depending on morphotype, with ‘nanulus’ type having 1-3 elongate, 4 quadrate to elongate, 5 or 6-10 transverse and macropterous individuals of the ‘debilis’ morphotype having 1-5 or 1-6 elongate and 7-10 or 8-10 distinctly transverse; pronotum about as wide as long to moderately transverse, moderately wider than head; disc with microsculpture as on head; elytra moderately to distinctly transverse, markedly variable from scarcely longer at sides than pronotum at middle to moderately longer (1.06-1.21, ‘nanulus’ morphotype), or distinctly longer than pronotum at middle (1.26-1.41, ‘debilis’ morphotype) (Fig. 12 ); disc of elytra with punctures varying from superficial, sparse and widely scattered (nanulus type) to slightly denser and coarser in individuals with the longest elytra (Fig. 12 ); wings as non-functional stubs or fully developed; abdomen generally sparsely punctate, denser at bases of tergites but variable, with punctation overall denser in ‘debilis’ morphotype; abdomen with dense, very fine microsculpture of transverse waves; abdominal tergite VII without or with palisade fringe.

Male. Sternite VIII with distinct emargination of variable depth and width; tergite X triangular, with moderately long, narrowly rounded apex; sternite IX varying from slightly expanded to broad at middle, with long, slender asymmetrical basal part and narrow, rounded apex; median lobe in ventral view with acute apex, sides of apex straight to acuminate resulting in a pinched appearance (Fig. 8L ), individuals from the Rockies with sides broadly arcuate (Fig. 8K ); median lobe in lateral view bearing a distinct tooth of variable distance from apex and with variably-sized emargination ventrad of tooth, apex narrow and rounded (Fig. 8O-Q ); paramere slender and varying from fusiform (basal constriction, widest subapically) to subparallel-sided or weakly narrowing apicad (Fig. 8M, N ); paramere with peg setae arranged in two rows, varying from well-organized to slightly disorganized and doubled in places, rows divergent from sides of paramere and weakly to strongly convergent basad in western individuals (Fig. 8N ); in eastern individuals, rows generally following the margins of paramere and not convergent basad (Fig. 8M ).

Female. Tergite X overall pentagonal, with emargination on each side of protruding, pointed apex, with longitudinal, median pigmented area, setae generally limited to midline (Fig. 9H-I ).

Distribution.

Canada: AB, BC. United States: CA, ID, MT, NV, OR, WA.

Broadly distributed along the western cordilleras on both the eastern and western sides of the continental divide (Fig. 11E ). At the northern edge of its western distribution, Q. debilis is entirely flightless and appears to extend eastward along the Fraser River in British Columbia to at least the Hope area but it is not clear how distantly east and west populations are separated by the drier, central interior, if at all.

Bionomics.

In the northern part of its range on the western side of the continental divide (British Columbia to Oregon, Fig. 12 ), Q. debilis is entirely flightless (wings as small stubs) and lives more or less in moist, forest litter-based microhabitats, including leaf litter, moss on rocks, treehole litter, and decaying wood and fungi, though it is sometimes collected in litter or moss along the water’s edge. Further south, south of northernmost California (Fig. 12 ), the species is more typically found in wet litter along creeks and most commonly fully winged with longer elytra. On the eastern side of the continental divide, examined specimens (all from Alberta) were fully winged with palisade fringe but with narrow elytra. In Alberta, specimens were collected in deciduous litter ( Populus sp.) in a forest and along a stream.

Comments.

Smetana (1971) treated Quediellus nanulus (as Quedius ) as a separate though variable species that could be confidently diagnosed from Q. debilis solely by the 'smaller aedeagus’ and in the key by the shorter and less narrow paramere with peg setae rows shorter. A more northern population of generally narrower, smaller-bodied individuals with shorter elytra was considered to correspond to Q. nanulus , while a more southern population of generally larger, more fusiform specimens with longer and broader elytra was considered to correspond to Q. debilis . Based on the material Smetana (1971) had available, there was some degree of geographic overlap in California, especially the northern Sierra Nevada (Lake Tahoe area).

An examination of dissected males from across this range on the western side of the continental divide, including many of the original specimens examined by Smetana (1971), revealed no reliable differences in the highly variable aedeagus in ventral or lateral view (but see below), despite remarkably disparate morphological forms at either end of the range of variability (Fig. 12 ). On average, individuals in the north of the distribution tend to have a paramere with a distinct basal constriction and long apical part, while individuals in the far south of the distribution have a more parallel-sided paramere with a shorter apical part (Fig. 8N ). However, there are exceptions, even within the same series. These trends do not correspond with the drawings presented in Smetana (1971) for Q. nanulus (northern) and Q. debilis (southern) and it is possible that they were reversed. The length of the rows of peg setae, number of peg setae and their distribution were all found to be highly variable and did not correspond to external morphotype. Often this variation was marked, even among individuals from the same locality, despite rather uniform external morphology. Congruently, sequenced individuals of the ‘debilis’ and ‘nanulus’ morphotypes (Fig. 10 , white circles) did not form separate clusters.

Individuals on the eastern side of the continental divide (Rocky Mountains) were considered by Smetana (1971) to belong to Q. nanulus . The three specimens examined (all Alberta) exhibited very subtle differences on the median lobe and paramere compared to all other western specimens (Fig. 8 ), though these differences may not hold when more males are dissected. Cluster analysis treated all specimens of Quediellus as a single OTU and BIN, with relatively high (3.27%) intraspecific divergence, likely due to the fact that this species is flightless and a poor disperser over much of its range (British Columbia to northern California). The single half-length sequence from the Rockies did not cluster separately from the western samples (Fig. 10 ). Therefore, Q. nanulus is here treated as a synonym of Q. debilis and both populations on either side of the continental divide are considered to be conspecific, leaving only one highly variable species of Quediellus .

Figures

Figure 5. A-C dorsal head A, B showing extent of head punctation (white arrow) and color of first antennomere base (black arrow) D-F elytral punctation and microsculpture A Paraquedius puncticeps (Horn) B P. marginicollis sp. nov. C, D Quediellus debilis (Horn) E Quedionuchus longipennis (Mannerheim) F Quedius densiventris (Casey). Abbreviations: af = anterior frontal puncture; b = basal puncture; pf = posterior frontal puncture; sa = supra-antennal puncture. Scale bars: 0.5 mm.

Figure 8. A aedeagus in ventral view B, C, D, G, H, K, L median lobe of aedeagus B, G, K, L in ventral view, C, D, H, O-Q in lateral view E, F, I, J, M, N underside of paramere showing peg setae A-F Paraquedius marginicollis sp. nov. E atypical specimen from Clallam County, Washington, United States G-J Paraquedius puncticeps (Horn) I lectotype, from Vancouver, British Columbia, Canada J non-type specimen from Vancouver Island K-Q Quediellus debilis (Horn), specimens from east (K, M) and west (L, M) sides of the continental divide. Filled circles = typical ' nanulus' morphotype; open circles = typical ' debilis' morphotype. Scale bars: 0.1 mm.

Figure 9. A-I female tergite X A Iratiquedius amabilis (Smetana) B I. mutator (Smetana) C I. prostans (Horn) D I. seriatus (Horn), evenly convex E I. uncifer sp. nov., discal impression F Paraquedius puncticeps (Horn) G P. marginicollis sp. nov. H-I Quediellus debilis (Horn). Pigmented area on tergite in E not shown for clarity but similar to I. seriatus. Scale bars: 0.1 mm.

Figure 10. Neighbor-joining trees of CO 1 barcode sequences for species of Iratiquedius, Paraquedius, and Quediellus, calculated under the Kimura- 2 model for pairwise distance. White circles indicate macropterous ' debilis' morphotypes of Q. debilis, all other Q. debilis are of brachypterous ' nanulus' morphotypes. Scale bar equivalent to 2 % divergence. Sequence length, including number of ambiguous base pairs (N's), is given at the end of each sample name.

Figure 11. Distributions of A Iratiquedius amabilis (Smetana) (circles), I. mutator (Smetana) (squares) B I. prostans (Horn) (black - specimens examined, white - literature records) C I. seriatus (Horn) (circles), I. uncifer sp. nov. (squares) D Paraquedius puncticeps (Horn) (circles), P. marginicollis sp. nov. (squares) E Quediellus debilis (Horn) (circles) (black - specimens examined, white - literature records).

Figure 12. Habitus and distribution of Quediellus debilis (Horn) morphotypes: brachypterous, palisade fringe absent (circle), brachypterous, palisade fringe present (square - habitus as in previous), winged, shorter and narrower elytra (triangle), winged, longer and broader elytra (hexagon). Scale bar = 1 mm.