Calyxochaetus binodatus
Creators: name: Runyon, Justin B.
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Diptera
Dolichopodidae
Calyxochaetus
Calyxochaetus binodatus

description: Calyxochaetus binodatus (Harmston & Knowlton)
(Figs 104, 116, 120, 132, 144)
Sympycnus binodatus Harmston & Knowlton, 1940: 397.
Calyxochaetus binodatus: Pollet et al. (2004: 74).
Type material examined. HOLOTYPE ♂, labeled: “ G.F. Knowlton / F.C. Harmston / Leeds, Utah / 9-13-1938 ”; “Type No/ 54297/ U.S.N.M.”; “Holo Type/ Sympycnus / binodatus / n. sp. F.C.H.-G.F.K.”; “ Sympycnus / binodatus / Det. 1940 F.C. Harmston” (USNM).
Other material examined. USA: Arizona: Cochise County: San Pedro River, 4 mi. E Sierra Vista, 4025 ft, 23.iv.2002, RLH & JBR (4♀, MTEC); Mohave County: Beaver Dam Wash, Beaver Dam, 1950 ft, 13.iv.2003, JBR & RLH (1♂, CNC; 1♂, 2♀, MTEC); Santa Cruz County: Patagonia Lake, 3750 ft, 15.iv.2003, JBR & RLH (1♂, 1♀, MTEC). New Mexico: Catron County: Glenwood, 1.vi.1972, Malaise, W.W. Wirth (2♂, USNM). Utah: San Juan County: Monticello, 30.viii.1950, FCH (1♂, FSCA); Washington County: Zion National Park, Birch Creek, 27.vii.1965, Malaise, W.J. Hanson (1♂, LACM); Beaver Dam Wash, Lytle Ranch Preserve, 1–2.vii.1987, W.J. Hanson (1♂, LACM); same data except, 19.viii–10.ix.1987 (1♂, LACM); Leeds, 27.vii.1940, G.F. Knowlton & FCH (2♂, MTEC); same data except, 25.iv.1941 (1♂, USNM); same data except, 20.iv.1951, FCH (2♂, FSCA).
Diagnosis. This is the only known species of Calyxochaetus whose males have two lamellae on the arista-like stylus (Fig. 104). Females have a semicircular postpedicel.
Redescription. Male. Wing length 2.7–3.0 mm. Head: Frons brown pruinose, sparser on either side of ocellar tubercle revealing some blue-violet ground color, not glabrous. Face silver-white, very narrow, about one ommatidium wide on ventral half. Antenna (Fig. 104) dark brown; scape stout; pedicel slightly longer and rounded medially; postpedicel semicircular; arista-like stylus with small oblong black lamella near 1/2 and larger rounded black lamella at apex. Palpus small, elongate oval, brown with apex yellow. Thorax: Pleura brown with thick gray pruinosity; metepimeron yellow on ventral half or less. Scutellum without distinct blue-violet reflections. Legs: Foreleg: Yellow, except coxa sometimes infuscated at very base, tarsomere 1 brown apically, tarsomere 2 sometimes yellow-brown, tarsomeres 3–5 dark brown. Femur with small yellow ventral setae on basal half. Tibia with small posterodorsal seta near 2/5. Tarsus (Fig. 116) with tarsomere 1 very short, about as wide as long. Tarsomere 3 with small (less than length tarsomere 4) curved anterodorsal apical seta. Tarsomere 4 with dorsal surface clothed in dense white microsetulae. Tarsomere 5 dorsally with sparser white microsetulae. Midleg: Yellow, except coxa infuscated with yellow ground color visible, tarsus brown from apex of tarsomere 1. Femur with anteroventral row of slender yellow to yellow-brown setae on basal three-fifths, increasing in size distally (largest subequal to femur width). Tibia with anteroventral full-length row of long (2X tibia width) slender yellow to yellow-brown setae, bent downward at tips, with conspicuous black preapical anteroventral seta. Tarsus (Fig. 120) short, half as long as tibia. Tarsomere 1 bowed slightly, longer than combined length of tarsomeres 2–5. Tarsomeres 2–4 widened and pointed anteriorly, with white microsetulae at anterior tips. Tarsomere 2 broadening from base anteriorly, longer and pointed anteroapically (overlapping tarsomere 3). Tarsomeres 3–4 small, subequal in size, wider than long. Hindleg: Yellow, except coxa infuscated at base, femur light brownish dorsoapically, tarsus brown from near middle of tarsomere 1. Femur with long (subequal to femur width) anteroventral brown seta near 3/4 (one specimen has two setae near 3/4). Tibia (Fig. 132) with clump of 3–5 very long (3X tibia width or longer) yellow-brown ventral setae at base, tibia slightly bowed just beyond clump. Wing: Hyaline. Anal lobe constricted at very base (basal to fork of R 2+3 and R 4+5), otherwise well-developed. Distal section of M 4 about 4X longer than crossvein dm-m. Abdomen: Tergite 1 brown, pruinose, concolorous to thorax. Tergites 2–3 mostly yellow, brown dorsally. Tergite 4 broadly yellow at base. Hypopygium: Postgonites with apical lobes narrow, apex rounded, translucent light brown.
Female. Wing length 3.0– 3.4 mm. Similar to male except as follows: Head: Face wide, nearly parallel-sided, gray. Antenna with postpedicel short, semicircular; arista-like stylus unmodified, blunted at apex. Palpus much larger, triangular, rounded apically, brown, with white setulae and brown setae. Thorax: Proepimeron with cluster of 5–6 small white hairs. Legs: Unmodified, without specialized setae. Hind femur with indistinct anteroventral seta near 3/4 (corresponding to long seta in male). Hind tarsomere 1 yellow with brown apex. Wing: Anal lobe broader, not constricted at base. Distal section of M 4 about 3X longer than crossvein dm-m. Abdomen: Tergites 2–3 with broad yellow lateral spots, remaining tergites brown.
Distribution and seasonal occurrence. Known from Arizona, New Mexico and southern Utah (Fig. 144). Adults have been collected from April to September.
Remarks. Adults were collected in Mojave County Arizona from low vegetation in the shade of the Highway 91 bridge at Beaver Dam, and in Santa Cruz County on shaded vegetation along Sonoita Creek near the inlet to Patagonia Lake.
description: Published as part of Runyon, Justin B., 2024, Revision of the genus Calyxochaetus Bigot (Diptera: Dolichopodidae: Sympycninae), pp. 1-74 in Zootaxa 5539 (1) on pages 50-52, DOI: 10.11646/zootaxa.5539.1.1, http://zenodo.org/record/14240426