Quedius horni Hatch 1957

Quedius horni Hatch, 1957

(Figs 1, 4, 5, 10A, 16B, 17, 21)

Quedius horni Hatch, 1957:216 [Type locality: Washington: Snohomish Co.: L. Ballinger]

References. KඈඋGൾ (1962b): 333 (characters, notes); Sආൾඍൺඇൺ (1965a): 39 (characters); (1971a): 146 (characters and distribution).

Material examined. CANADA: BඋංඍංඌH Cඈඅඎආൻංൺ: 20 mi. E. Hope, Manning Pk., [49.18, -120.97], ex river debris, 21.VI.1968, leg. Campbell & Smetana (1 CNC); Tsawwassen, [49.01, -123.08], 19.V.1968, leg. Campbell & Smetana (1 CNC). Hൺංൽൺ Gඐൺංං: Queen Charlotte Island [Haida Gwaii], Skowkona Creek, 7.9km NW O. C.City, [53.33, -132.13], ex dung and carrion traps, 19-29.VII.1983, leg. J.M. Campbell (1 CNC); 7.9km NW Queen Charlotte City, [53.31, -132.14], dung trap, 19-29. VII.1983, leg. J.M. Campbell (1 CNC). Vൺඇർඈඎඏൾඋ Iඌඅൺඇൽ: Mesachie Lake, Forest Experiment Station, [48.82, -124.13], 15-31.VII.1979, leg. I. Smith (2 CNC); Vancouver Island, [49.76, -125.46] (4 CNC). USA: AඅൺඌKൺ: Auke Bay, 16.2km N Juneau, [58.38, -134.65], sifting moss, 9.VI.1981, leg, Bright (1 CNC). OඋൾGඈඇ: Blodgett, [44.59, -123.52], VI.1927, leg. Darlington (1 MCZ); Hood River County, 10 mi S Mount Hood at Clinger Springs,[45.4, -121.55], 1310 m, 8.VII.1978, leg.L.& N. Herman (1 CNC); Mt.Hood, South Side, [45.29, -121.7], 7.VI.1927, leg. Darlington (1 MCZ). WൺඌHංඇGඍඈඇ: Olympic National Park, Hoh Ranger Station, [47.85, -123.93], 182 m, 13.V.1968, leg. Campbell & Smetana (1 CNC); Olympic National Park, 4-6 mi SE Soleduck Campground, [47.93, -123.77], 944 m, 15.VIII.1979, leg. J.M. & B.A. Campbell (1 CNC).

Redescription. Measurements JJ (n = 4): HW = 1.64– 1.69 (1.67); HL = 1.36–1.40 (1.39); HL/HW 0.82–0.84 (0.83); PW = 2.02–2.22 (2.13); PL = 1.82–2.00 (1.92); PL/PW 0.88–0.91 (0.90); EW = 2.11–2.31 (2.21); EL = 2.04–2.29 (2.11); EL/EW 0.88–1.01 (0.96); EL/PL 1.02– 1.14 (1.10); PW/HW 1.44–1.59 (1.54); forebody length 5.24–5.69 (5.42). ♀♀ (n = 2): HW = 1.62–1.71 (1.67); HL = 1.36–1.42 (1.39); HL/HW 0.83–0.84 (0.83); PW = 2.02–2.16 (2.09); PL = 1.78–2.00 (1.89); PL/PW 0.88–0.93 (0.90); EW = 2.13–2.29 (2.21); EL = 2.04–2.16 (2.10); EL/EW 0.94–0.96 (0.95); EL/PL 1.08–1.15 (1.11); PW/ HW 1.49–1.52 (1.50); forebody length 5.18–5.58 (5.38).

Medium sized, robust species; body black (Fig. 10A).

Head black, distinctly transverse, with eyes medium sized (EyL/TL = 1.76–2.06 (1.91)), microsculpture of transverse waves, with two interocular punctures between anterior frontal punctures (Fig. 6G); antennae and palpi pale reddish with most of antennomeres 1–3 clearly darkened; all antennomeres elongate, except apical antennomere almost transverse.

Thorax: pronotum black, slightly wider than long, clearly 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 sparsely punctured and pubescent; elytra most often reddish brown, but occasionally fully darkened or dark with reddish sutural margins, uniformly pubescent, with punctures clearly separated, quadrate or slightly wider than long, slightly longer than pronotum; legs reddish brown with inner face of tibia and inner surface femur darkened and tarsi paler.

Abdomen black, tergites uniformly punctured, with clear iridescence.

Male. Aedeagus (Figs 16B, 17): paramere rather broad, with clear basal attenuation and pointed apex, reaching to apex of median lobe, with small sensory peg setae forming thin row in a semi-circle near edge of paramere, except at pointed apex; median lobe broad with sudden constriction to a point at apex, on parameral side with two fang-like subapical teeth basad; internal sac with elongate and broad sclerites.

Differential diagnosis. Quedius horni can be distinguished from Q. laticollis and Q. strenuus by the presence of two additional setiferous punctures between the anterior frontal punctures. It can be distinguished from Q. labradorensis by the darker body and the clearly darkened antennomeres 1–3. Quedius horni can be clearly distinguished from other members of the molochinoides -group (Q. altanai, Q. lanei and Q. molochinoides) only by the spoon-like shape of the paramere, which has a clear basal attenuation and broadening towards pointed apex, with its peg setae situated in a semi-circle near the edge of the of the paramere below its pointed apex. However, this species co-occurs with other species of the molochinoides -group only in Alaska, which makes such detailed examination for diagnostic purposes within the group less necessary anywhere else.

Bionomics. Little is known about the habitat requirements of Q. horni. It seems to prefer wet environments, as it has been collected in moist habitats from sea level to an elevation slightly above 1000 meters. Most specimens were collected in coastal sites or inland near rivers and creeks suggesting its close association with wet habitats near water bodies. For example, the species was found in river flood debris and on beaches under driftwood in British Columbia, in moss at Auke Bay, Alaska, in a dung trap on Haida Gwaii, and in forest litter around large firs at Mary’s Peak, Oregon (Sආൾඍൺඇൺ 1971a). Immature specimens were collected in late May at Tsawwassen, British Columbia and in early July on Mt. Hood, Oregon (Sආൾඍൺඇൺ 1971a). Based on the records near coastal sites the species is most likely somewhat halotolerant.

Distribution. Quedius horni is now known from the Pacific Northwest, from Oregon to southern Alaska, including Vancouver Island and Haida Gwaii (most of ecoregion 7.1; Fig. 21). It can be found at coastal and riverine sites and to mid elevation of the Cascades and Mount Olympia. This revision, including barcoding, confirmed its first record from southern Alaska, and thus extended the species range significantly to the north. It is still uncertain how far south the species occurs, with the current southernmost record coming from central Oregon. Based on the extent of ecoregion 7.1, this may extent along the coast into California.