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

description: Calyxochaetus harmstoni sp. nov.
(Figs 35, 46, 63, 68, 71)
Type material. HOLOTYPE ♂, labeled: “ Hartsel, Colo./ June 9, 1964 / F. C. Harmston ”; “HOLOTYPE/ Calyxochaetus / harmstoni / J.B. Runyon [red label]” (CAS) (Fig. 68). PARATYPES: USA: Colorado: Same data as holotype (3♂, CAS); Gunnison County: Crested Butte, 8.viii.1968, F.C. Harmston (1♂, FSCA).
Diagnosis. Males of this species can be distinguished from others in the C. cilifemoratus species group by the wide face (Fig. 68, inset). The lamella on the arista-like stylus of C. harmstoni sp. nov. is similar in shape to C. distortus but is broader (cf. Figs 33 and 35).
Description. Male. Wing length 2.8–2.9 mm. Head: Frons with brown pruinosity, only slightly thinner on either side of ocellar tubercle, not glabrous. Face silver-gray, slightly narrowing to clypeus but relatively wide, about 5 ommatidia wide at clypeus (Fig. 68, inset). Antenna (Fig. 35) dark brown; scape long and laterally flattened, subequal to combined length of pedicel and postpedicel; postpedicel oval, longer than wide; arista-like stylus longer than height of head, apical half with denser, slightly longer microtrichia, apical lamella elongate and subtriangular with rounded apex. Palpus small, oval, brown basally becoming light yellow apically, with apical setulae yellow. Thorax: Pleura dark brown with gray pruinosity; metepimeron concolorous with pleura, yellow just above hind coxa. Legs: Foreleg: Yellow with tarsomere 1 narrowly brown dorsally at apex, tarsus brown from apex of tarsomere 2. Tibia slender, without outstanding setae. Tarsus slender and long (1.75X tibia length). Tarsomere 1 very short, about as wide as long. Tarsomere 2 about two-thirds length of tibia and slightly longer than combined length of tarsomeres 3–4, without long fine anterior setae at apex. Tarsomere 3 about three-quarters length of tarsomere 4. Tarsomere 4 slightly bowed, with slightly longer pale dorsal setulae on apical third. Tarsomere 5 dorsoventrally flattened, slightly wider than tarsomere 4. Midleg: Yellow, except coxa infuscated with yellow ground color visible; tarsus brown from apex of tarsomere 1. Femur with very short slender yellow ventral setae (length half femur width or less). Tibia slender, not noticeably bowed, without specialized setae. Tarsus (Fig. 46) not unusually slender, slightly shorter than tibia length. Tarsomere 1 about half tibia length and slightly longer than combined length of tarsomeres 2–5; apex with 2 fine curved anterior setae, longest subequal to tarsomere 2 length. Tarsomere 2 with basal third slightly swollen, bearing 3 fine curved pale anterior setae. Tarsomeres 2–4 subequal in length and relatively short (each less than one-third tarsomere 1 length). Tarsomere 4 with a few slightly longer setae (longest slightly longer than tarsomere width) along anterior edge; longer (subequal to tarsomere 5 length) fine curved pale anterior seta at apex. Tarsomere 5 greater than half tarsomere 4 length, with about 2 short fine setae along anterior edge. Hindleg: Yellow, except coxa sometimes faintly infuscated at base, femur faintly brownish dorsoapically, tibia becoming light brown on apical third, tarsus brown with tarsomere 1 light brown on basal half. Apical half of femur with anteroventral row of long (longest greater than femur width) yellow setae, apical-most seta in this row shorter and black, with posteroventral row of short setae on apical half; posterior preapical seta present. Tibia with row of finer, denser ventral setae on basal half (length subequal to tibia width). Wing (Fig. 63): Similar to C. distortus except as follows: Wing slightly broader basal to apex of R 1, anal lobe smaller and not projecting as strongly. Distal section of M 4 about 3X longer than crossvein dm-m. Abdomen: Tergite 2 mostly yellow laterally. Tergite 3 mostly yellow or yellow-brown laterally. Hypopygium: Postgonite apical lobes narrow, apex rounded, dark brown.
Female. Unknown.
Distribution and seasonal occurrence. Known from two high elevation sites (ca 2700 m) in Colorado (Fig. 71), from adults collected in June and August.
Etymology. Named in honor of Fred C. Harmston (1911–1995), who collected all known specimens of this species and many other Calyxochaetus specimens. His efforts have greatly expanded our knowledge of the distribution and diversity of Calyxochaetus. Most of his extensive collection was deposited in the FSCA, but also originally at Utah State University, Logan (USU Diptera collections have since been transferred to LACM) and CAS (Hurley et al. 2004).
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 30-32, DOI: 10.11646/zootaxa.5539.1.1, http://zenodo.org/record/14240426