Calyxochaetus lacrima, Runyon, 2024

Runyon, Justin B., 2024, Revision of the genus Calyxochaetus Bigot (Diptera: Dolichopodidae: Sympycninae), Zootaxa 5539 (1), pp. 1-74 : 59-60

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.14240398
persistent identifier	https://treatment.plazi.org/id/FD1A87BF-A516-FFDE-50D3-FB1DFDA6FCEA
treatment provided by	Plazi
scientific name	Calyxochaetus lacrima
status	sp. nov.

Treatment

Calyxochaetus lacrima sp. nov.

( Figs 115, 119 View FIGURES 104–119 , 131 View FIGURES 120–131 , 136 View FIGURES 132–138 , 140 View FIGURES 139–143 , 147 View FIGURES 147–148 )

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 View FIGURES 139–143 ) . 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 View FIGURES 104–119 ). This is the only species in the C. frontalis group whose males have long ventral setae on the hind femur ( Fig. 136 View FIGURES 132–138 ).

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 View FIGURES 104–119 ) 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 View FIGURES 104–119 ): 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 View FIGURES 120–131 ) 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 View FIGURES 132–138 ) with row of longer ventral setae on apical half. Tibia ( Fig. 136 View FIGURES 132–138 ) 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 View FIGURES 147–148 ) 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 View FIGURES 104–119 ).