Calyxochaetus insolitus (Van Duzee)

Runyon, Justin B., 2024, Revision of the genus Calyxochaetus Bigot (Diptera: Dolichopodidae: Sympycninae), Zootaxa 5539 (1), pp. 1-74 : 46-47

Calyxochaetus insolitus (Van Duzee)

( Figs 95, 97, 99, 102 )

Sympycnus insolitus Van Duzee, 1932: 20 .

Calyxochaetus insolitus : Foote et al. (1965: 528).

Type material examined. HOLOTYPE ♂, labeled: “Aspen, Colo./ July 24–27, 1919 / F.4396A”; “About 39°11′ N./ 106°49′ W./ 8000 ft. ”; “( Calyxochaetus )/ Sympycnus / insolitus / Holotype.VanDuzee” (AMNH).

Other material examined. CANADA: Alberta: Cypress Hills, Reesor Lake, 30.viii.2002, JBR (2♂, 3♀, MTEC); Cypress Hills , Spruce Coulee Reservoir , 31.viii.2002, JBR (2♀, MTEC); Cypress Hills , Graburn campground, 1.ix.2002, JBR (1♂, 2♀, MTEC); Cypress Hills , Graburn Creek , 5 km SW Graburn campground, 1.ix.2002, JBR (1♂, 1♀, CNC) . USA: Colorado: Larimer County: 8 km NW Estes Park, 2500 m, 5.viii.1973, P.H. Arnaud, Jr (1♂, CAS); Logan County: Merino , 7.ix.1972, FCH (1♂, FSCA) . Idaho: Butte County: Little Cottonwood Creek, N43°28.58′ W113°35.40′, 21.vii.2009, JBR (1♂, 1♀, MTEC); Kootenai County : Bayview, vii.1973, FCH (1♂, FSCA); near Carlin Bay , 10 mi. N Harrison, 14–20.vii.1980, sweep, W.J. Turner (2♂, WSU); same data except, 17–21.vii.1985 (2♂, WSU) . Montana: Gallatin County: Olsen Creek Road, 2.4 mi E Bridger Creek Road, seep, 5.viii.2002, JBR (1♂, MTEC); Bozeman , Montana State University campus, duck pond, 17.vii.2002, JBR (1♂, 1♀, MTEC); Bozeman Creek , 6 mi. S Bozeman, N45°35.08′ W111°01.42′, 26.vii.2008, JBR (1♂, 1♀, MTEC); Limestone Creek , N45°36.78′ W111°00.51′, 25.vii.2010, JBR (1♂, 1♀, MTEC); same data except, 12.vii.2023 (1♂, 2♀, MTEC); Glacier County : Babb, 24.vii.1970, FCH (1♂, FSCA); Granite County : Flint Creek , 3.1 mi. N Philipsburg, 17.vii.2002, RLH & JBR (1♂, 4♀, MTEC); Madison County : Cliff Lake , inlet near island, 44°46.016′N 111°33.000′W, 1.viii.2015, JBR (2♂, MTEC); small creek near Madison River , N44°49.898′ W111°30.750′, 6.viii.2016, JBR (4♂, 1♀, MTEC); Park County : Pine Creek campground, 21.vii.2002, JBR (1♂, MTEC); Box Canyon trailhead, 45°16.40′N 110°15.01′W, 26.vii.2015, JBR (2♂, MTEC); Sweet Grass County : small creek/wetland at road [Main Boulder Road], 45°22.41′N 110°12.56′W, 26.vii.2015, JBR (2♂, MTEC); same data except, wetland below road, 45°28.285′N 110°11.976′W (7♂, 2♀, MTEC) . Oregon: Baker County: Wetmore campground, 44°31′40″N 118°18′26″W, 13.vii–11.viii.2017, Malaise, S. Fitzgerald (1♂, CNC); Union County : North Powder , 25.vii.1965, FCH (1♂, FSCA) . South Dakota: Custer County: Custer, 13.vii.1963, FCH (2♂, FSCA); Pennington County : Hill City , 13.vii.1963, FCH (1♂, FSCA) . Utah: Cache County: Logan Canyon, 4.vii.1972, FCH (4♂, FSCA; 1♂, LACM); Logan Canyon, 9.vii.1979, G.F. Knowlton (1♂, LACM); Logan Canyon, Turner campground, 16–30.viii.1985, W.J. Hanson (1♂, LACM); Daggett County: Manila, 10.viii.1946, FCH (1♂, MTEC); 48 mi. N Vernal, 23.vii.1988, R. Wharton (1♂, TAMU); Duchesne County : Mountain Home , 19.vii.1940, G.F. Knowlton (1♂, CNC); Garfield County : Boulder Mountain , 26.viii.1978, FCH (1♂, LACM); San Juan County : La Sal Mountains , 8.viii.1983, FCH (1♂, FSCA); Sevier County : Clear Creek , 28.vii.1939, G.F. Knowlton & FCH (1♂, CNC); Utah County : Mount Timpanogos , 4.viii.1946, FCH (1♂, CNC); Wasatch County : Little Hobble Creek , 4.5 mi. SE Wallsburg, 6200 ft, 26.vi.2001, RLH (3♂, 1♀, MTEC) . Washington: Benton County: Hanford Site, ALE., Rattlesnake Ridge , spring, N46°24.391′ W119°36.312′, 8.vii.1994 (1♂, 1♀, WSU); Spokane County : Valleyford, 6.viii.1924, ALM (2♂, USNM); Mica, 14.vii.1918, ALM (2♂, USNM) . Wyoming: Lincoln County: Greys River , 6290 ft, N43°03.99′ W110°49.89′, 26.vii.2012, JBR (1♂, MTEC) .

Diagnosis. Males can be recognized by having fore tarsomeres 1 and 2 subequal in length ( Fig. 97 ).

Redescription. Male. Wing length 2.7–3.1 mm. Head: Frons with brown pruinosity, usually sparser on either side of ocellar tubercle revealing blue-green ground color, not glabrous. Face silver-gray, narrow, triangular, about one ommatidium wide at clypeus. Antenna ( Fig. 95 ) brown; scape laterally flattened, flared apically, shorter than postpedicel; postpedicel elongate oval, usually with weakly pointed apex (sometimes with weak ventral notch near 2/3), about 1.5X as long as wide (slightly longer in a few specimens); arista-like stylus with elongate narrow apical lamella, with apex rather pointed. Palpus small, oval, brown with small whitish setulae. Thorax: Pleura brown with gray pruinosity, usually with small yellow areas including part of postpronotal lobe, anteroventral corner of anepisternum, below halter, and sometimes along sutures; metepimeron wholly yellow. Legs: Foreleg ( Fig. 97 ): Yellow, except tarsus becoming light brown from near middle of tarsomere 3. Tibia not swollen, with small posterodorsal seta near 1/3. Tarsomere 1 subequal in length to tarsomere 2. Tarsomere 3 very slightly longer than tarsomere 2, dorsal surface clothed with short dense microsetulae. Tarsomere 4 about 1.5X longer than tarsomere 3, dorsal surface with short dense microsetulae. Midleg: Yellow, except coxa usually lightly infuscated at base and along anterodorsal edge, tarsus brown from near apex of tarsomere 1. Tarsus ( Fig. 99 ) of nearly equal width throughout length, tarsomeres 2–4 with ventral surface flattened and bare. Tarsomere 1 slightly greater than half tibia length, with black anterior seta at apex. Tarsomere 2 with 2–3 very small slender sinuous posteroventral setae near base (length subequal to tarsomere width), with 2 longer sinuous anterior setae (near 1/3 and beyond 1/2) and about 4 shorter sinuous anteroventral setae spaced along length, apex square. Tarsomeres 3–4 each with 2 very small slender widely spaced sinuous anterior setae. Hindleg: Yellow, except femur light brown on apical third and tarsus brown from apex of tarsomere 1. Femur with about 5 slender ventral setae on apical half, increasing in length distally (longest greater than femur width). Tibia without specialized ventral setae near base. Wing: Evenly tinged with light brown. Elongate oval and narrow with anal lobe gradually narrowed at base, posterior margin slightly flattened opposite crossvein dm-m; indistinct excavation at apex of M 4. Crossvein dm-m with weak longitudinal crease near midpoint. Distal section of M 4 straight, about 3.5X longer than crossvein dm-m. Abdomen: Tergites 2–3 mostly yellow, usually brown dorsally and along posterior margins. Tergite 4 sometimes yellow basally. Hypopygium: Postgonites with apical lobes pointed, translucent light brown.

Female. Wing length 3.1–3.4 mm. Similar to male except as follows: Head: Face wider (subequal to postpedicel width), nearly parallel-sided, gray.Antenna with postpedicel short, wider than long, subquadrate with apex flattened; arista-like stylus unmodified. Palpus much larger, triangular, rounded apically, dark brown with gray pruinosity and yellow setae. Thorax: Proepimeron with 2–5 small white hairs. Legs: Unmodified, without specialized setae. Hind femur light brown to brown on apical one-fourth or less, with short anteroventral seta near 4/5 (corresponding to long seta in male). Wing: Broader with posterior margin more evenly rounded, anal lobe larger and more rounded at base. Distal section of M 4 about 3X longer than crossvein dm-m. Abdomen: Tergite 2 varying from having small yellow lateral spot at base to being wholly yellow on basal half. Tergite 3 with small to large yellow area laterally, remaining tergites dark brown.

Distribution and seasonal occurrence. Known from in or near the central and northern Rocky Mountains of the USA and from the Cypress Hills of southeastern Alberta, Canada ( Fig. 102 ). Adults have been collected June to September.

Remarks. I have collected adults in shaded wetlands with abundant moss in forests and beneath large willows in otherwise open wetlands.

Figures

FIGURES 95–103. Male antennae (lateral view), legs and known geographical distributions of the Calyxochaetus insolitus species group. 95. C. insolitus (Van Duzee). 96. C. pennarista (Harmston & Knowlton). 97. C. insolitus, fore tibia and tarsus, posterior view. 98. C. pennarista, fore tibia and tarsus, posterior view. Arrows show relatively long fore tarsomere 1. 99. C. insolitus, mid tarsus, posterior view. Inset shows mid tarsomeres in ventral view. 100. C. pennarista, left mid tarsus, dorsal view. 101. C. pennarista, right mid tarsus, dorsal view. 102. Known geographical distribution of C. insolitus. 103. Known geographical distribution of C. pennarista. Scale bars = 0.5 mm; arista-like styli approximately 1 mm long.