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

description: Calyxochaetus lacrima sp. nov.
(Figs 115, 119, 131, 136, 140, 147)
Type material. HOLOTYPE, ♂, labeled: “ MEXICO: Nuevo Leon / Santiago, Potrero/ Redondo. 10.V.85 / A. Contreras R.”; “HOLOTYPE/ Calyxochaetus / lacrima / J.B. Runyon [red label]” (CNC) (Fig. 140). PARATYPES: Mexico: Same data as holotype (5♂, 7♀, CNC).
Diagnosis. The very large, nearly round apical lamella on the arista-like stylus of males is diagnostic (Fig. 115). This is the only species in the C. frontalis group whose males have long ventral setae on the hind femur (Fig. 136).
Description. Male: Wing length 2.8–3.1 mm. Head: Frons brown pruinose with large glabrous shiny blue-violet spot on either side of ocellar tubercle. Face silver, about 2 ommatidia wide on ventral half. Antenna (Fig. 115) dark brown; scape relatively short and stout, with apex narrowly yellow medially; postpedicel elongate oval, about as long as wide; arista-like stylus bare and becoming very thin before broadening into large (subequal in size to postpedicel), teardrop-shaped lamella. Palpus small, elongate oval, brown at base and broadly yellow apically, with yellow setulae. Thorax: Pleura brown with light gray pruinosity, yellowish below halter and above mid coxa; metepimeron yellow. Scutellum with distinct blue-violet reflections medially. Legs: Foreleg (Fig. 119): Yellow, except tarsus becoming brown from near apex of tarsomere 3. Tibia slender, with small posterodorsal seta near 1/3. Tarsomere 1 very short, slightly longer than wide. Tarsomere 2 about half tibia length. Tarsomere 3 about half tarsomere 2 length, slightly broadened apically and pointed dorsoapically with a few short distally curved black dorsal setulae across apex. Tarsomere 4 about 1.5X tarsomere 3 length, slightly narrowed at base, slightly thicker near 2/3 (appearing slightly bowed, in anterior and posterior views), with row of small black dorsal setulae across apex. Midleg: Yellow, except tarsus brown from near apex of tarsomere 1. Tarsus (Fig. 131) length subequal to tibia length. Tarsomere 1 longer than combined length of tarsomeres 2–5. Tarsomere 2 subequal to combined length of tarsomeres 3–5, slightly broadened apically with small anteroapical projection bearing a few short pale setulae. Tarsomeres 3–4 subequal in size, short, wider than long, with short pale anterior setulae (most are hooked). Tarsomere 5 distinctly longer than combined length of tarsomeres 3–4. Hindleg: Yellow, except tarsus brown from near apex of tarsomere 1. Femur (Fig. 136) with row of longer ventral setae on apical half. Tibia (Fig. 136) with posteroventral row of 4–5 longer, weakly curvate setae on basal half. Wing: Evenly tinged light brown. Elongate oval and rather narrow, with anal area somewhat reduced. Distal section of M 4 about 3X longer than crossvein dm-m. Abdomen: Tergite 1 yellow-brown to yellow laterally. Tergites 2–3 almost wholly yellow. Tergite 4 (and sometimes tergites 5–6) yellow ventrally at base. Sternites yellow. Hypopygium: Postgonites with apical lobes very narrow, sharply pointed, translucent with narrow brown stripe along dorsal edge.
Female. Wing length 2.9–3.5 mm. Similar to male except as follows: Head: Face wider (subequal to postpedicel width), nearly parallel-sided, gray-silver. Antenna with postpedicel about as wide as long, rounded but apex slightly flattened in a few specimens; arista-like stylus unmodified. Palpus much larger, triangular, narrowly rounded apically, yellow-brown. Thorax: Proepimeron with cluster of 2–4 small white hairs. Legs: Unmodified, without specialized setae. Wing: Anal lobe broader. Distal section of M 4 about 2X longer than crossvein dm-m. Abdomen: Tergites 2–3 mostly yellow, but browner along posterior margins and sometimes narrowly brown dorsally.
Distribution and seasonal occurrence. Known only from the village of Potrero Redondo in Nuevo León, Mexico (Fig. 147) and collected in May.
Etymology. The specific epithet is the Latin noun lacrima (teardrop) and refers to the shape of the lamella on the arista-like stylus of males (Fig. 115).
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 59-60, DOI: 10.11646/zootaxa.5539.1.1, http://zenodo.org/record/14240426