Calyxochaetus anisoaristus, Runyon, 2024

Runyon, Justin B., 2024, Revision of the genus Calyxochaetus Bigot (Diptera: Dolichopodidae: Sympycninae), Zootaxa 5539 (1), pp. 1-74 : 17-19

publication ID	https://doi.org/ 10.11646/zootaxa.5539.1.1
publication LSID	lsid:zoobank.org:pub:7BDB9666-CA90-40BF-8F65-B9897CDA1F2B
DOI	https://doi.org/10.5281/zenodo.14240316
persistent identifier	https://treatment.plazi.org/id/FD1A87BF-A53C-FFF7-50D3-FA8DFC6FFE92
treatment provided by	Plazi
scientific name	Calyxochaetus anisoaristus
status	sp. nov.

Treatment

Calyxochaetus anisoaristus sp. nov.

( Figs 26, 39 View FIGURES 26–44 , 64 View FIGURES 64–68 , 71 View FIGURES 70–73 )

Type material. HOLOTYPE ♂, labeled: “ Ninette , Manitoba / 28-VII-1958 / R.L. Hurley ”; “HOLOTYPE/ Calyxochaetus / anisoaristus / J.B. Runyon [red label]” ( CNC) ( Fig. 64 View FIGURES 64–68 ).

Diagnosis. This species is distinguished from others in the C. cilifemoratus species group by the combination of yellow metepimeron ( Fig. 64 View FIGURES 64–68 ), arista-like stylus with apical lamella ( Fig. 26 View FIGURES 26–44 ), and foreleg with tarsomeres 3 and 4 subequal in length ( Fig. 39 View FIGURES 26–44 ).

Description. Male. Wing length 1.9 mm. Head: Frons brown pruinose. Face silver-white, narrowing to about 2 ommatidia wide at clypeus. Antenna ( Fig. 26 View FIGURES 26–44 ) brown, scape yellow-brown; scape laterally flattened, subequal to combined length of pedicel and postpedicel; postpedicel oval, about as long as wide; arista-like stylus with apical oblanceolate lamella. Palpus small, oval, brown with whitish apex. Thorax: Pleura brown with thick gray pruinosity; metepimeron wholly yellow. Legs: Foreleg: Coxa, femur and tibia wholly yellow, tarsus brown from near middle of tarsomere 3. Tibia slender, without outstanding setae, with obvious anterior comb-like row of close-set yellow setulae at apex. Tarsomere 1 very short, about as long as wide. Tarsomere 2 with small (less than half tarsomere 3 length), yellow, distally projected anterior seta at apex. Tarsomeres 3 and 4 subequal in length ( Fig. 39 View FIGURES 26–44 ). Midleg: Coxa yellow, slightly infuscated near base, femur and tibia wholly yellow, tarsus brown from apical third of tarsomere 1. Femur with row of short (longest about half femur width), slender, yellow ventral setae on basal half. Tarsomere 1 with fine sinuous yellow anterior seta at apex. Tarsomere 2 with basal half slightly swollen and bearing 4 fine sinuous yellow anterior setae (basal-most seta shortest). Tarsomere 4 with fine sinuous yellow anterior seta at apex. Tarsomere 5 with 2–3 shorter, fine anterior setae. Tarsomeres decreasing in length apically, tarsomere 1 subequal to combined length of tarsomeres 2–5. Hindleg: Coxa, femur and tibia yellow, tarsus brown from about middle of tarsomere 1. Femur with anteroventral row of slender yellow to yellow-brown setae on apical half, increasing in length distally (longest 1.5X femur width), posterior preapical seta absent. Tibia with ventral row of short, slender setae (less than tibia width) on basal third, with ventral seta near 1/2 and 3/4. Wing: Similar to C. isoaristus ( Fig. 60 View FIGURES 56–63 ) except as follows: Anal area slightly narrower, evenly rounded basal to apex of M 4, without obvious indentation at apex of M 4. Abdomen: Tergite 1 mostly brown, yellow laterally adjacent to metepimeron. Tergites 2–4 yellow laterally at base, tergites otherwise dark brown. Sternites yellow. Hypopygium: Postgonites with apical lobes rounded, dark brown.

Female. Unknown.

Distribution and seasonal occurrence. Known only from the holotype collected in southern Manitoba ( Fig. 71 View FIGURES 70–73 ), in late July.

Etymology. The specific epithet is from the Greek aniso (unequal) + aristus, in reference to this species being similar to C. isoaristus but having a lamella on the arista-like stylus.