Gnathusa tenuicornis Fenyes

Klimaszewski, Jan, Webster, Reginald P., Langor, David W., Bourdon, Caroline, Hammond, H. E. James, Pohl, Greg R. & Godin, Benoit, 2014, Review of Canadian species of the genera Gnathusa Fenyes, Mniusa Mulsant & Rey and Ocyusa Kraatz (Coleoptera, Staphylinidae, Aleocharinae), ZooKeys 412, pp. 9-40 : 14-17

2. Gnathusa tenuicornis Fenyes Figure 2 a–m, Map 2

Gnathusa tenuicornis Fenyes 1921: 26, Moore and Legner 1975: 458, Klimaszewski and Winchester 2002: 58.

Diagnosis.

Body length 2.5-3.7 mm, sides subparallel; body colour light brown to almost black, with antennae, tarsi and often elytra and apical part of abdomen rust-brown; integumental microsculpture dense and surface strongly glossy; head round (Fig. 2a) to somewhat quadrate (Fig. 2b) and almost as wide as pronotum, labrum with short fine setae but lacking coarse spines; pronotum transverse, subequal to slightly narrower than maximum width of elytra, corners somewhat angular; elytra at suture subequal in length to pronotum; abdomen subparallel; antennal articles 6-10 subquadrate, last article short and broadly oval (Fig. 2a, b). MALE: tergite VIII widely truncate apically (Fig. 2e); sternite VIII slightly pointed at apex (Fig. 2f); median lobe of aedeagus with tubus almost straight and apex pointed ventrally in lateral view (Fig. 2c). FEMALE: tergite VIII truncate apically (Fig. 2g); sternite VIII rounded apically (Fig. 2h); spermatheca pipe-shaped, with spherical capsule and long, thin, and slightly sinuate stem, neck weakly sclerotized, and neck to capsule angle variable (Fig. 2d).

Distribution.

This native Nearctic species was described from specimens captured in Glacier, British Columbia, later recorder from Yokon, and is herein recorded for the first time from Alberta and New Brunswick (four female specimens tentatively identified as this species) (Map 2). In the United States, this species was previously known from California ( Fenyes 1921, Moore and Legner 1975, Klimaszewski and Winchester 2002), and is herein recorded for the first time from Oregon.

Bionomics.

Adults were captured in a clear-cut Sitka spruce forest on Vancouver Island and in moss and gravel at the edge of small pools in British Columbia ( Klimaszewski and Winchester 2002). Other adults were found in a subalpine meadow at 3000 feet, in cold moss and gravel along the edges of streams. The Yukon specimens were taken from mixed aspen and spruce forest by sifting litter. In west-central Alberta, adults were collected in pitfall traps deployed in Upper Cordilleran coniferous forests, including subxeric lodgepole pine forests, mesic white spruce and lodgepole pine stands and and spruce-dominated subhygric and hygric forests, but not in deciduous-dominated forest or in grassy or shrubby meadows. The New Brunswick specimens were taken from moss and leaves under alders near a brook in an eastern white-cedar swamp and from under cobblestones and gravel in sand on a partially shaded cobblestone bar near the outflow of a brook into a river. Adults were captured from May through August.

Locality data.

CANADA: Alberta: Waterton Lakes National Park, Cameron Lake, 5450', 4.VIII.1976, J.M. Campbell (CNC) 1 male; 20 km S Hinton, 20.VII.1989, pitfall trap, D. Langor coll., site C, trap 6, conifer study (NoFC) 1 male; 20 km S Hinton, 26.VI.1989, D. Langor coll., site C, trap 6, conifer study (NoFC) 1 male; 26 km SE Hinton, 7 km S of Gregg River Rd., 53.220°N, 117.343°W, Ecosite Surrogacy Study, Ecoregion: UF, Ecosite H1, Stand H104, pitfall trap # 4, 15-29.VI. J. Hammond et al. (NoFC) 2 males, 1 female; 31 km SE Hinton, 3 km of Highway 40, 53.593°N, 117.925°W, Ecosite Surrogacy Study, Ecoregion: UF, Ecosite D1, Stand D108, pitfall trap # 6, 11.V-3.VI. J. Hammond et al. (NoFC) 1 male; 32 km NW Hinton, 3 km W of Highway 40, 53.586°N, 117.954°W, Ecosite Surrogacy Study, Ecoregion: UF, Ecosite E1, Stand E103, pitfall trap # 5, 11.V-4.VI. J. Hammond et al. (NoFC) 1 male; 32 km NW Hinton, 1 km W of Hay River Rd., 53.760°N, 117.652°W, Ecosite Surrogacy Study, Ecoregion: UF, Ecosite I102, Stand I102, pitfall trap # 2, 13. V– 3.VI. 2004, J. Hammond et al. (NoFC) 1 male, 1 female; 43 km SE Hinton, 1.5 km N Coalspur, 53.194°N, 117.046°W, Ecosite Surrogacy Study, Ecoregion: UF, Ecosite B1, Stand B103, pitfall trap # 6, 1-15.VI.2004, J. Hammond et al. (NoFC) 1 male; 55 km N Hinton, north side of Polecat Rd., 53.855°N, 117.926°W, Ecosite Surrogacy Study, Ecoregion: UF, Ecosite H1, Stand H103, pitfall trap # 3, 3-17.VI.2004, J. Hammond et al. (NoFC) 1 male, 1 female; 65 km N Hinton, 5 km W of Wright Rd., 53.995°N, 117.656°W, Ecosite Surrogacy Study, Ecoregion: UF, Ecosite E1, Stand E118, pitfall trap # 5, 2-16.VI.2004, J. Hammond et al. (NoFC) 2 females; 69.5 km N Hinton, 0.7 km NW of JV Haul Rd., 54.017°N, 117.618°W, Ecosite Surrogacy Study, Ecoregion: UF, Ecosite D1, Stand D103, pitfall trap # 5, 1-16.VI.2004, J. Hammond et al. (NoFC) 1 female. British Columbia: Glacier, Fenyes collection (CAS) 1 female [holotype]; Nitinat, Heather Mtn., subalpine meadow at 3000', 14.VII.1979, I.M. Smith, moss on seepage slope (CNC) 1 female; Forbidden Plateau, Murray Meadows, 3400', 21.VII.1975, J.M. and B.A. Campbell (CNC) 1 female; Queen Charlotte Islands, 10.5 km NW Rennell, Sound Rd., Ghost Main Rd., 900', J.M. Campbell, cold moss along stream (CNC) 1 male; Queen Charlotte Islands, Moresby Is., Mt. Moresby, 25.VII.1983, 2100', J.M. Campbell, ex gravel at edge of stream (CNC) 1 male; 20 mi E Hope, Manning Pk., 21.VI.1968, Campbell and Smetana (CNC) 1 female; Copper River Valley, A37574/P4-1-1, 6. VI– 5.VII.1996, pitfall trap, J. Lemieux (LFC) 1 female; same data except: 5. VII– 12.VIII.1996, (LFC) 1 male; Upper Carmanah Valley, UTM: 10U CK 803005, 16.VII-30.VII.1991, CC MT3, N. Winchester (LFC) 2 females [additional records from the same locality Klimaszewski and Winchester 2002]. Yukon Territory: Whitehorse, Paddy’s Pond, 6.V.2007, 60.7067°N, 135.0917°W, 649 m, litter sifting, mixed aspen and spruce forest, B. Godin (ECW) 1 male [record from Klimaszewski et al. 2012]. New Brunswick: Restigouche Co., MacFarlane Brook Protected (Natural) Area, 47.6018°N, 67.6263°W, 25.V.2007, R.P. Webster // old growth eastern white cedar swamp, in moss & leaves under alders near stream (RWC) 2 females; Jacquet River Gorge PNA, 47.8257°N, 66.0779°W, 24.V.2010, R.P. Webster // partially shaded cobblestone bar near outflow of brook at Jacquet River, under cobblestones & gravel on sand (RWC) 1 female; Mount Atkinson, 441 m elev., 41.8192°N, 68.2618°W, 7.VII.2011, R.P. Webster // Boreal forest, small shaded spring-fed brook with mossy margin, sifting moss (LFC) 1 female.

UNITED STATES OF AMERICA: Alaska: Kenai Peninsula, 2 mi NE Soldotna, 10.VI.1978, Smetana and Becker (CNC) 1 female. Oregon: Mt. Hood, Timberline Lodge Road, 4500 –5000’, 28.VI.1974, A. and D. Smetana (CNC) 1 male.

Comments.

We have tentatively included the females from New Brunswick as belonging to this species. The difference in body colour, the slightly different shape of pronotum and the temples of the head in the New Brunswick and western specimens we attribute to infraspecific variations because the shape of spermatheca and the tergites and sternite VIII are similar in females of both populations. The study of males from New Brunswick is critical to confirm our identification. The specimens from the north usually are darker than the specimens from more southern localities in many species of aleocharines.